Original article
Relative importance of the determinants of serum levels of 25-hydroxy vitamin D in patients with chronic kidney disease
Importancia relativa de los factores determinantes de los niveles séricos de 25-hidroxi-colecalciferol en la enfermedad renal crónica
Read
9725
Timeswas read the article
2372
Total PDF
7353
Total HTML
Share statistics
array:24 [ "pii" => "S201325141630116X" "issn" => "20132514" "doi" => "10.1016/j.nefroe.2016.11.010" "estado" => "S300" "fechaPublicacion" => "2016-09-01" "aid" => "205" "copyrightAnyo" => "2016" "documento" => "article" "crossmark" => 0 "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/" "subdocumento" => "fla" "cita" => "Nefrologia (English Version). 2016;36:510-6" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 4781 "formatos" => array:3 [ "EPUB" => 356 "HTML" => 3795 "PDF" => 630 ] ] "Traduccion" => array:1 [ "es" => array:19 [ "pii" => "S0211699516300376" "issn" => "02116995" "doi" => "10.1016/j.nefro.2016.01.017" "estado" => "S300" "fechaPublicacion" => "2016-09-01" "aid" => "205" "documento" => "article" "crossmark" => 0 "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/" "subdocumento" => "fla" "cita" => "Nefrologia. 2016;36:510-6" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 7315 "formatos" => array:3 [ "EPUB" => 346 "HTML" => 6089 "PDF" => 880 ] ] "es" => array:13 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Original</span>" "titulo" => "Importancia relativa de los factores determinantes de los niveles séricos de 25-hidroxi-colecalciferol en la enfermedad renal crónica" "tienePdf" => "es" "tieneTextoCompleto" => "es" "tieneResumen" => array:2 [ 0 => "es" 1 => "en" ] "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "510" "paginaFinal" => "516" ] ] "titulosAlternativos" => array:1 [ "en" => array:1 [ "titulo" => "Relative importance of the determinants of serum levels of 25-hydroxy vitamin D in patients with chronic kidney disease" ] ] "contieneResumen" => array:2 [ "es" => true "en" => true ] "contieneTextoCompleto" => array:1 [ "es" => true ] "contienePdf" => array:1 [ "es" => true ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0005" "etiqueta" => "Figura 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1046 "Ancho" => 1554 "Tamanyo" => 80152 ] ] "descripcion" => array:1 [ "es" => "<p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">Representación gráfica del porcentaje de pacientes con déficit de vitamina D (niveles séricos de 25-hidroxi-colecalciferol <<span class="elsevierStyleHsp" style=""></span>15<span class="elsevierStyleHsp" style=""></span>ng/ml) según la puntuación de predicción basada en edad, sexo, actividad física, proteinuria y bicarbonato sérico. En cada subgrupo de puntuación se especifica el número total de pacientes (n) y el porcentaje de ellos con déficit de vitamina D.</p>" ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "Fernando Caravaca-Fontán, Boris Gonzales-Candia, Enrique Luna, Francisco Caravaca" "autores" => array:4 [ 0 => array:2 [ "nombre" => "Fernando" "apellidos" => "Caravaca-Fontán" ] 1 => array:2 [ "nombre" => "Boris" "apellidos" => "Gonzales-Candia" ] 2 => array:2 [ "nombre" => "Enrique" "apellidos" => "Luna" ] 3 => array:2 [ "nombre" => "Francisco" "apellidos" => "Caravaca" ] ] ] ] ] "idiomaDefecto" => "es" "Traduccion" => array:1 [ "en" => array:9 [ "pii" => "S201325141630116X" "doi" => "10.1016/j.nefroe.2016.11.010" "estado" => "S300" "subdocumento" => "" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:1 [ "total" => 0 ] "idiomaDefecto" => "en" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S201325141630116X?idApp=UINPBA000064" ] ] "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0211699516300376?idApp=UINPBA000064" "url" => "/02116995/0000003600000005/v3_201705130058/S0211699516300376/v3_201705130058/es/main.assets" ] ] "itemSiguiente" => array:20 [ "pii" => "S2013251416301031" "issn" => "20132514" "doi" => "10.1016/j.nefroe.2016.11.006" "estado" => "S300" "fechaPublicacion" => "2016-09-01" "aid" => "189" "copyright" => "Sociedad Española de Nefrología" "documento" => "article" "crossmark" => 0 "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/" "subdocumento" => "fla" "cita" => "Nefrologia (English Version). 2016;36:517-22" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 3447 "formatos" => array:3 [ "EPUB" => 348 "HTML" => 2435 "PDF" => 664 ] ] "en" => array:13 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Original article</span>" "titulo" => "Incidence, mortality, and prevalence of end-stage chronic renal disease in the Bajo Lempa region of El Salvador: A ten-year community registry" "tienePdf" => "en" "tieneTextoCompleto" => "en" "tieneResumen" => array:2 [ 0 => "en" 1 => "es" ] "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "517" "paginaFinal" => "522" ] ] "titulosAlternativos" => array:1 [ "es" => array:1 [ "titulo" => "Incidencia, mortalidad y prevalencia de enfermedad renal crónica terminal en la región del Bajo Lempa, El Salvador: 10 años de registro comunitario" ] ] "contieneResumen" => array:2 [ "en" => true "es" => true ] "contieneTextoCompleto" => array:1 [ "en" => true ] "contienePdf" => array:1 [ "en" => true ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0005" "etiqueta" => "Fig. 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 728 "Ancho" => 1656 "Tamanyo" => 84152 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">Annual incidence rates of patients with stage 5 CKD or ESRD per million population and patient deaths per 100,000 in a population of 19,223 in the Bajo Lempa region in El Salvador, 2004–2013.</p>" ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "Ramón García-Trabanino, Carolina Hernández, Adrián Rosa, Jesús Domínguez Alonso" "autores" => array:5 [ 0 => array:2 [ "nombre" => "Ramón" "apellidos" => "García-Trabanino" ] 1 => array:2 [ "nombre" => "Carolina" "apellidos" => "Hernández" ] 2 => array:2 [ "nombre" => "Adrián" "apellidos" => "Rosa" ] 3 => array:2 [ "nombre" => "Jesús" "apellidos" => "Domínguez Alonso" ] 4 => array:1 [ "colaborador" => "On behalf of the Emergency Social Fund for Health (FSES) of the canton Tierra Blanca, Department of Usulután, El Salvador" ] ] ] ] ] "idiomaDefecto" => "en" "Traduccion" => array:1 [ "es" => array:9 [ "pii" => "S0211699516300212" "doi" => "10.1016/j.nefro.2016.03.018" "estado" => "S300" "subdocumento" => "" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:1 [ "total" => 0 ] "idiomaDefecto" => "es" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0211699516300212?idApp=UINPBA000064" ] ] "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S2013251416301031?idApp=UINPBA000064" "url" => "/20132514/0000003600000005/v1_201612260003/S2013251416301031/v1_201612260003/en/main.assets" ] "itemAnterior" => array:19 [ "pii" => "S2013251416300773" "issn" => "20132514" "doi" => "10.1016/j.nefroe.2016.09.003" "estado" => "S300" "fechaPublicacion" => "2016-09-01" "aid" => "204" "copyright" => "Sociedad Española de Nefrología" "documento" => "article" "crossmark" => 0 "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/" "subdocumento" => "fla" "cita" => "Nefrologia (English Version). 2016;36:503-9" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 4644 "formatos" => array:3 [ "EPUB" => 371 "HTML" => 3469 "PDF" => 804 ] ] "en" => array:13 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Original article</span>" "titulo" => "Diabetic kidney disease: Is there a non-albuminuric phenotype in type 2 diabetic patients?" "tienePdf" => "en" "tieneTextoCompleto" => "en" "tieneResumen" => array:2 [ 0 => "en" 1 => "es" ] "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "503" "paginaFinal" => "509" ] ] "titulosAlternativos" => array:1 [ "es" => array:1 [ "titulo" => "Enfermedad renal diabética: ¿hay un fenotipo de no albuminuria en diabéticos tipo 2?" ] ] "contieneResumen" => array:2 [ "en" => true "es" => true ] "contieneTextoCompleto" => array:1 [ "en" => true ] "contienePdf" => array:1 [ "en" => true ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0005" "etiqueta" => "Fig. 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1055 "Ancho" => 1585 "Tamanyo" => 169953 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">Flow-chart of study. (DM Diabetes mellitus; CKD Chronic Kidney Disease; GFR Glomerular filtration rate; ACR Urine Albumin/Creatinine Ratio; A-DKD Albuminuric Diabetic Kidney Disease (DKD); NA-DKD Non-albuminuric DKD).</p>" ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "Ivo Laranjinha, Patrícia Matias, Sofia Mateus, Filipa Aguiar, Patrícia Pereira, Miguel Perneta Santos, Rui Costa, Ana Lourenço, José Guia, José Diogo Barata, Luís Campos" "autores" => array:11 [ 0 => array:2 [ "nombre" => "Ivo" "apellidos" => "Laranjinha" ] 1 => array:2 [ "nombre" => "Patrícia" "apellidos" => "Matias" ] 2 => array:2 [ "nombre" => "Sofia" "apellidos" => "Mateus" ] 3 => array:2 [ "nombre" => "Filipa" "apellidos" => "Aguiar" ] 4 => array:2 [ "nombre" => "Patrícia" "apellidos" => "Pereira" ] 5 => array:2 [ "nombre" => "Miguel" "apellidos" => "Perneta Santos" ] 6 => array:2 [ "nombre" => "Rui" "apellidos" => "Costa" ] 7 => array:2 [ "nombre" => "Ana" "apellidos" => "Lourenço" ] 8 => array:2 [ "nombre" => "José" "apellidos" => "Guia" ] 9 => array:2 [ "nombre" => "José Diogo" "apellidos" => "Barata" ] 10 => array:2 [ "nombre" => "Luís" "apellidos" => "Campos" ] ] ] ] ] "idiomaDefecto" => "en" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S2013251416300773?idApp=UINPBA000064" "url" => "/20132514/0000003600000005/v1_201612260003/S2013251416300773/v1_201612260003/en/main.assets" ] "en" => array:20 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Original article</span>" "titulo" => "Relative importance of the determinants of serum levels of 25-hydroxy vitamin D in patients with chronic kidney disease" "tieneTextoCompleto" => true "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "510" "paginaFinal" => "516" ] ] "autores" => array:1 [ 0 => array:4 [ "autoresLista" => "Fernando Caravaca-Fontán, Boris Gonzales-Candia, Enrique Luna, Francisco Caravaca" "autores" => array:4 [ 0 => array:4 [ "nombre" => "Fernando" "apellidos" => "Caravaca-Fontán" "email" => array:1 [ 0 => "fcaravacaf@gmail.com" ] "referencia" => array:2 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">a</span>" "identificador" => "aff0005" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">*</span>" "identificador" => "cor0005" ] ] ] 1 => array:3 [ "nombre" => "Boris" "apellidos" => "Gonzales-Candia" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0010" ] ] ] 2 => array:3 [ "nombre" => "Enrique" "apellidos" => "Luna" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0010" ] ] ] 3 => array:3 [ "nombre" => "Francisco" "apellidos" => "Caravaca" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0010" ] ] ] ] "afiliaciones" => array:2 [ 0 => array:3 [ "entidad" => "Servicio de Nefrología, Hospital Ramón y Cajal, Madrid, Spain" "etiqueta" => "a" "identificador" => "aff0005" ] 1 => array:3 [ "entidad" => "Servicio de Nefrología, Hospital Infanta Cristina, Badajoz, Spain" "etiqueta" => "b" "identificador" => "aff0010" ] ] "correspondencia" => array:1 [ 0 => array:3 [ "identificador" => "cor0005" "etiqueta" => "⁎" "correspondencia" => "<span class="elsevierStyleItalic">Corresponding author</span>." ] ] ] ] "titulosAlternativos" => array:1 [ "es" => array:1 [ "titulo" => "Importancia relativa de los factores determinantes de los niveles séricos de 25-hidroxi-colecalciferol en la enfermedad renal crónica" ] ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0005" "etiqueta" => "Fig. 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1046 "Ancho" => 1554 "Tamanyo" => 77927 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">Graph showing the percentage of patients with vitamin D deficiency (serum 25-hydroxycholecalciferol levels <15<span class="elsevierStyleHsp" style=""></span>ng/ml) according to predictive score based on age, gender, physical activity, proteinuria and serum bicarbonate. The total number of patients (<span class="elsevierStyleItalic">n</span>) in each scoring subgroup and the percentage with vitamin D deficiency are specified.</p>" ] ] ] "textoCompleto" => "<span class="elsevierStyleSections"><span id="sec0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0075">Introduction</span><p id="par0005" class="elsevierStylePara elsevierViewall">In recent years, interest in diagnosing vitamin D deficiency by measuring 25-hydroxycholecalciferol (25(OH)D) in serum has increased significantly. A significant proportion of the general population has low levels of 25(OH)D,<a class="elsevierStyleCrossRefs" href="#bib0195"><span class="elsevierStyleSup">1,2</span></a> but deficiency is found in most patients with chronic conditions, especially chronic kidney disease (CKD).<a class="elsevierStyleCrossRefs" href="#bib0205"><span class="elsevierStyleSup">3–8</span></a></p><p id="par0010" class="elsevierStylePara elsevierViewall">The cause of the deficiency would seem to be multifactorial. Factors related to exposure to ultraviolet light (UV),<a class="elsevierStyleCrossRefs" href="#bib0225"><span class="elsevierStyleSup">7,9,10</span></a> and comorbidity such as diabetes<a class="elsevierStyleCrossRefs" href="#bib0245"><span class="elsevierStyleSup">11–13</span></a> may explain much of the deficit of vitamin D. In patients with CKD, the reduction in glomerular filtration rate,<a class="elsevierStyleCrossRefs" href="#bib0260"><span class="elsevierStyleSup">14–16</span></a> proteinuria<a class="elsevierStyleCrossRefs" href="#bib0205"><span class="elsevierStyleSup">3,17–19</span></a> and commonly used drugs<a class="elsevierStyleCrossRef" href="#bib0290"><span class="elsevierStyleSup">20</span></a> may also have a significant influence. However, the relative individual importance of all these factors in vitamin D deficiency is unknown.</p><p id="par0015" class="elsevierStylePara elsevierViewall">Multiple linear regression analysis is the method of choice to establish the degree of variation of a dependent variable using the information offered by independent variables.</p><p id="par0020" class="elsevierStylePara elsevierViewall">One of the assumptions that must be met for prediction models to be reliable and accurate is that independent variables have no significant correlation between each other.<a class="elsevierStyleCrossRef" href="#bib0295"><span class="elsevierStyleSup">21</span></a> This requirement is very difficult to meet when analysing the potential determinants of vitamin D levels in a population with CKD. There is a high degree of association between factors such as physical activity or exposure to ultraviolet radiation (UV) and age, gender and comorbidity, or between proteinuria and the prescription of certain drugs such as angiotensin inhibitors and receptor blockers. This complicates the interpretation and significance of the regression coefficients and the relative importance of each of these potential determinants.</p><p id="par0025" class="elsevierStylePara elsevierViewall">One way of overcoming the difficulties generated by the multicollinearity in a multivariate linear regression model is determination, in addition to the standardized coefficients (beta), of the structure coefficients which provide additional information about the bivariate relationship between a predictor and the observed effect, without the influence of other predictors in the model.<a class="elsevierStyleCrossRefs" href="#bib0295"><span class="elsevierStyleSup">21–23</span></a></p><p id="par0030" class="elsevierStylePara elsevierViewall">“Weighting of the relative importance” is an accredited method for establishing the proportional contribution of each predictor to the coefficient of determination (<span class="elsevierStyleItalic">R</span><span class="elsevierStyleSup">2</span>), correcting the effects of the cross-correlation between predictors.<a class="elsevierStyleCrossRefs" href="#bib0295"><span class="elsevierStyleSup">21–23</span></a></p><p id="par0035" class="elsevierStylePara elsevierViewall">The aim of this study was to analyze the determinants of 25(OH)D levels in a cohort of patients with advanced CKD not on dialysis, and establish the relative importance of the variables found to be part of the best predictive model.</p></span><span id="sec0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0080">Materials and methods</span><span id="sec0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0085">Patients</span><p id="par0040" class="elsevierStylePara elsevierViewall">All incident patients in an advanced CKD clinic between February 2012 and March 2015 were included consecutively. All were over 18 and resided in the province of Badajoz, Spain. Patients being treated with vitamin D supplements (ergocalciferol, cholecalciferol or 25-hydroxycholecalciferol), or with drugs that interact with 25(OH)D metabolism, such as carbamazepine, were excluded from the study.</p><p id="par0045" class="elsevierStylePara elsevierViewall">The following data were gathered when taking the medical history from the patient or from their medical notes and included as potential covariates in the analysis: age; gender; body mass index; Davies comorbidity index; date of extraction; reduction in physical activity; vitamin D analogs; statins; angiotensin-converting enzyme (ACE) inhibitors and/or angiotensin-receptor antagonists (ARA); and xanthine oxidase (XO) inhibitors (allopurinol or febuxostat).</p><p id="par0050" class="elsevierStylePara elsevierViewall">According to the time of year of the extraction, we put together a qualitative ordinal variable in which winter was scored as 0, autumn 1, spring 2 and summer 3.</p><p id="par0055" class="elsevierStylePara elsevierViewall">Decrease in physical activity was considered when the patients reported no physical activity outside their homes and little exposure to the sun.</p></span><span id="sec0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0090">Laboratory tests</span><p id="par0060" class="elsevierStylePara elsevierViewall">The 25(OH)D concentrations were measured using the electrochemiluminescence method (LIAISON<span class="elsevierStyleSup">®</span> 25 OH Vitamin D TOTAL Assay, DiaSorin Inc., Stillwater, USA). The measuring range of this method covers concentrations from 4 to 150<span class="elsevierStyleHsp" style=""></span>ng/ml, with intra-assay imprecision (coefficient of variation) of ≤5.5% and functional sensitivity of 4<span class="elsevierStyleHsp" style=""></span>ng/ml.</p><p id="par0065" class="elsevierStylePara elsevierViewall">Other biochemical parameters analyzed as potential determinants of 25(OH)D levels were: glomerular filtration rate (MDRD); serum albumin (immunoturbidimetric, ADVIA 2400 Chemistry System, Siemens Healthcare Diagnostics, USA); high-sensitivity C-reactive protein (turbidity meter, Siemens Healthcare Diagnostics); and proteinuria measured in 24<span class="elsevierStyleHsp" style=""></span>h urine collection, expressing the results as g of protein per g of creatinine excretion. Also included as variables were serum uric acid concentrations (ADVIA, Siemens) and venous bicarbonate (ABL800 FLEX gas analyser, Radiometer Ibérica).</p><p id="par0070" class="elsevierStylePara elsevierViewall">Serum calcium, phosphorus, magnesium and PTH concentrations were not considered as potential determinants of 25(OH)D levels.</p></span><span id="sec0025" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0095">Statistical methods</span><p id="par0075" class="elsevierStylePara elsevierViewall">To establish the best model of association between 25(OH)D levels (dependent variable) and the independent variables, multivariate linear regression was used. Independent variables were selected by an automatic stepwise selection procedure. In addition to the coefficient of multiple determination (<span class="elsevierStyleItalic">R</span><span class="elsevierStyleSup">2</span>) of the model, standardized partial regression coefficients (beta) were also calculated.</p><p id="par0080" class="elsevierStylePara elsevierViewall">The best resulting model was assessed for multicollinearity, this being considered significant if the condition number was greater than 20, according to the Belsley et al. criteria.<a class="elsevierStyleCrossRef" href="#bib0310"><span class="elsevierStyleSup">24</span></a></p><p id="par0085" class="elsevierStylePara elsevierViewall">To determine the relative importance of each independent variable in the model, we calculated structure coefficients and performed a Johnson relative weights analysis and significance tests in order to compare the relative importance of the predictors.<a class="elsevierStyleCrossRefs" href="#bib0300"><span class="elsevierStyleSup">22,23</span></a> The relative importance of each variable is expressed as a percentage of contribution to multiple <span class="elsevierStyleItalic">R</span>.</p><p id="par0090" class="elsevierStylePara elsevierViewall">For comparisons of continuous variables, Student's <span class="elsevierStyleItalic">t</span> test, ANOVA or Mann-Whitney test were used, according to the distribution characteristics of the variable. We used the <span class="elsevierStyleItalic">χ</span><span class="elsevierStyleSup">2</span> test for comparison of categorical variables.</p><p id="par0095" class="elsevierStylePara elsevierViewall">The results are expressed as mean or median and standard deviation or ranges respectively. <span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>0.05 was considered to be statistically significant.</p><p id="par0100" class="elsevierStylePara elsevierViewall">Statistical analyses were performed with the IBM-SPSS Statistics 21.0 program (IBM Corp. Armonk, USA). For the Johnson relative weights analysis, we used the FIRE program created by Lorenzo-Seva and Ferrando.<a class="elsevierStyleCrossRef" href="#bib0305"><span class="elsevierStyleSup">23</span></a> This program uses an SPSS Syntax Editor window, through which the calculations are performed.</p></span></span><span id="sec0030" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0100">Results</span><p id="par0105" class="elsevierStylePara elsevierViewall">The total number of patients studied was 397, but 30 were excluded because they were already receiving vitamin D supplements (27 patients) or were being treated with carbamazepine (3 patients).</p><p id="par0110" class="elsevierStylePara elsevierViewall">The characteristics of the remaining 367 patients who made up the study group are shown in <a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a>. The total number of patients with serum 25(OH)D levels below 20<span class="elsevierStyleHsp" style=""></span>ng/ml was 298 (81%).</p><elsevierMultimedia ident="tbl0005"></elsevierMultimedia><p id="par0115" class="elsevierStylePara elsevierViewall">No significant differences were found in the 25(OH)D concentrations according to the time of year the extraction was made (winter 13.8<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>8.1<span class="elsevierStyleHsp" style=""></span>ng/ml; autumn 12.9<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>6.5<span class="elsevierStyleHsp" style=""></span>ng/ml; spring 13.7<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>7.2<span class="elsevierStyleHsp" style=""></span>ng/ml; and summer 14.1<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>6.7<span class="elsevierStyleHsp" style=""></span>ng/ml; <span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.886, ANOVA).</p><p id="par0120" class="elsevierStylePara elsevierViewall"><a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a> also shows the differences between patients with sufficiency or lack of vitamin D. The most notable characteristics of those with vitamin D deficiency were as follows: older women; more comorbidity; less physical activity; a more pronounced reduction in average serum albumin concentration and increased proteinuria, with no significant differences in the estimated glomerular filtration rate; and, to a lesser extent, being treated with xanthine oxidase inhibitors.</p><p id="par0125" class="elsevierStylePara elsevierViewall">By multivariate linear regression, the best predictive model for 25(OH)D levels consisted of age, gender, decreased physical activity, proteinuria and serum bicarbonate (<a class="elsevierStyleCrossRef" href="#tbl0010">Table 2</a>). Variables that were not part of the best equation but came close in their significance were the comorbidity index, serum uric acid and treatment with xanthine oxidase inhibitors (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.05).</p><elsevierMultimedia ident="tbl0010"></elsevierMultimedia><p id="par0130" class="elsevierStylePara elsevierViewall">Analysis of the multicollinearity of the model showed a condition number of 19.57, i.e. at the limit for considering the model to have severe multicollinearity.</p><p id="par0135" class="elsevierStylePara elsevierViewall">The independent variables that showed significant bilateral correlation were age and physical activity – the greater the age, the less physical activity – (<span class="elsevierStyleItalic">R</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.357; <span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>0.0001), and age and gender – males younger than females – (<span class="elsevierStyleItalic">R</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>−0.121; <span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.021).</p><p id="par0140" class="elsevierStylePara elsevierViewall">Analysis of relative weights (<a class="elsevierStyleCrossRef" href="#tbl0010">Table 2</a>) showed proteinuria to be the variable with the greatest relative importance, followed by age. The sum of both variables contributed almost 50% to multiple <span class="elsevierStyleItalic">R</span>. The other 50% was divided among the following independent variables: decline in physical activity; gender (more vitamin D deficiency in females); and serum bicarbonate concentrations (the lower the bicarbonate levels, the more vitamin D deficiency) (<a class="elsevierStyleCrossRef" href="#tbl0010">Table 2</a>).</p><p id="par0145" class="elsevierStylePara elsevierViewall">With the best predictive model variables transformed into categoricals, a score was set for prediction of severe 25(OH)D deficiency (concentrations <15<span class="elsevierStyleHsp" style=""></span>ng/ml). Each of the following categories added one point: aged over 70; being female; decreased physical activity; proteinuria >1<span class="elsevierStyleHsp" style=""></span>g/g of creatinine; and serum bicarbonate below 22<span class="elsevierStyleHsp" style=""></span>mEq/l.</p><p id="par0150" class="elsevierStylePara elsevierViewall">The cut-offs for transforming continuous variables into discrete variables were estimated by observing points with greater sensitivity and specificity in receiver operating characteristic curves (Youden index).</p><p id="par0155" class="elsevierStylePara elsevierViewall"><a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a> shows the percentage of patients with severe 25(OH)D deficiency according to the predictive score ranging from 0 to 5. Approximately 90% of patients with scores of 4 or 5 had severe vitamin D deficiency, while only 25% of those with none of these characteristics had vitamin D deficiency (<a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>).</p><elsevierMultimedia ident="fig0005"></elsevierMultimedia></span><span id="sec0035" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0105">Discussion</span><p id="par0160" class="elsevierStylePara elsevierViewall">The results of this study show that over 80% of patients with advanced CKD have vitamin D deficiency. The predictors of vitamin D concentrations with the most relative importance were proteinuria, age, gender, reduction in physical activity and serum bicarbonate.</p><p id="par0165" class="elsevierStylePara elsevierViewall">A previous study on a large Spanish population, the OSERCE Study,<a class="elsevierStyleCrossRef" href="#bib0205"><span class="elsevierStyleSup">3</span></a> describes the main parameters of mineral and bone disorder associated with CKD, including 25(OH)D levels. However, in that study, it was not among their objectives to identify the determinants of 25(OH)D levels, and even if it had been, they would not have been able to. In fact, they concluded that 25(OH)D levels are associated only with PTH and, to a small extent, with proteinuria.<a class="elsevierStyleCrossRef" href="#bib0205"><span class="elsevierStyleSup">3</span></a></p><p id="par0170" class="elsevierStylePara elsevierViewall">The design of our study left aside the relationship between 25(OH)D and bone mineral metabolism parameters (probably more effect than cause), and focused on establishing what was or were its determinants. Therefore, unlike the OSERCE study, the predictive information provided by our study on 25(OH)D levels is much more rigorous and thorough, and the analysis included the majority of the known potential determinants. The main original aspect of our study though is the statistical analysis for the “relative importance” weights, i.e. we not only determined which factors were associated qualitatively with 25(OH)D levels, but we also quantified the importance of each factor to explain the association model and compensate for the collinearity inherent to these studies.</p><p id="par0175" class="elsevierStylePara elsevierViewall">Due to the frequent cross-correlation between the variables proposed as determinants of a dependent variable, the resulting models can be inaccurate and the results can lead to confusing interpretations.<a class="elsevierStyleCrossRef" href="#bib0295"><span class="elsevierStyleSup">21</span></a> This could be the case when analysing the determinants of 25(OH)D concentrations in CKD.</p><p id="par0180" class="elsevierStylePara elsevierViewall">Use of the relative weights statistical method makes it possible to estimate the relative importance of each independent variable in a prediction model, computing the effect of multicollinearity.<a class="elsevierStyleCrossRefs" href="#bib0295"><span class="elsevierStyleSup">21–23</span></a></p><p id="par0185" class="elsevierStylePara elsevierViewall">In this study, proteinuria was the variable with the greatest relative importance in the prediction model.</p><p id="par0190" class="elsevierStylePara elsevierViewall">Other studies have also shown an association between the magnitude of proteinuria and the degree of vitamin D deficiency in patients with CKD<a class="elsevierStyleCrossRefs" href="#bib0205"><span class="elsevierStyleSup">3,17,18</span></a> or in renal transplant recipients.<a class="elsevierStyleCrossRef" href="#bib0285"><span class="elsevierStyleSup">19</span></a></p><p id="par0195" class="elsevierStylePara elsevierViewall">In some studies in which proteinuria was not measured, an association was found between vitamin D deficiency and hypoalbuminaemia,<a class="elsevierStyleCrossRefs" href="#bib0210"><span class="elsevierStyleSup">4,7,18</span></a> or the presence of glomerular diseases that tend to present with severe proteinuria.<a class="elsevierStyleCrossRefs" href="#bib0245"><span class="elsevierStyleSup">11,13,25</span></a></p><p id="par0200" class="elsevierStylePara elsevierViewall">Since most of the studies on this subject have been cross-sectional, we cannot conclude that there is a causal relationship between proteinuria and vitamin D deficiency.</p><p id="par0205" class="elsevierStylePara elsevierViewall">A high percentage of circulating vitamin D is bound to proteins (DBP and albumin), which are filtered in large quantities through the sick glomeruli and this can lead to significant losses in urine.<a class="elsevierStyleCrossRef" href="#bib0260"><span class="elsevierStyleSup">14</span></a> A plausible hypothesis to explain this association would therefore be a vitamin D depletion effect caused by proteinuria.</p><p id="par0210" class="elsevierStylePara elsevierViewall">Further data to support the hypothesis that vitamin D deficiency is associated with protein depletion are the lower 25(OH)D levels in patients on peritoneal dialysis; these patients tend to have higher protein loss than those treated with haemodialysis.<a class="elsevierStyleCrossRefs" href="#bib0320"><span class="elsevierStyleSup">26,27</span></a></p><p id="par0215" class="elsevierStylePara elsevierViewall">However, there might also be a hypothetical proteinuric effect associated with vitamin D deficiency. Although it has been found that vitamin D analogs (calcitriol, paricalcitol) have a reducing effect on proteinuria, a study has also shown significant reductions in albuminuria after repletion of vitamin D levels with cholecalciferol.<a class="elsevierStyleCrossRef" href="#bib0330"><span class="elsevierStyleSup">28</span></a> Proteinuria might therefore not only be a cause but also an effect of vitamin D deficiency, which would reinforce the interpretation of its greater relative importance.</p><p id="par0220" class="elsevierStylePara elsevierViewall">Other aspects such as older age, female gender or decreased physical activity are more predictable factors that contribute to lower vitamin D levels.<a class="elsevierStyleCrossRefs" href="#bib0255"><span class="elsevierStyleSup">13,29</span></a></p><p id="par0225" class="elsevierStylePara elsevierViewall">One finding difficult to interpret in this study is the significant association, although with less relative importance, between the concentration of serum bicarbonate and 25(OH)D levels.</p><p id="par0230" class="elsevierStylePara elsevierViewall">Acidosis does not cause any effects on the synthesis or degradation of 25(OH)D.<a class="elsevierStyleCrossRefs" href="#bib0340"><span class="elsevierStyleSup">30,31</span></a> Ketoacidosis<a class="elsevierStyleCrossRef" href="#bib0350"><span class="elsevierStyleSup">32</span></a> or ketogenic diets<a class="elsevierStyleCrossRef" href="#bib0355"><span class="elsevierStyleSup">33</span></a> could cause reductions in 25(OH)D levels, but this assumption does not seem relevant among our patients.</p><p id="par0235" class="elsevierStylePara elsevierViewall">A common link between acidosis and 25(OH)D reduction in the clinical context of proteinuric kidney disease could be proximal tubule dysfunction.</p><p id="par0240" class="elsevierStylePara elsevierViewall">A more dysfunctional proximal tubule, in addition to possibly causing a more severe acidosis (type <span class="elsevierStyleSmallCaps">2</span> renal tubular acidosis) could lead to increased urinary losses of 25(OH)D due to lack of reabsorption of proteins (DBP, albumin), requiring tubular expression of multiligand endocytic receptors, such as megalin and cubilin.<a class="elsevierStyleCrossRef" href="#bib0360"><span class="elsevierStyleSup">34</span></a> Vitamin D deficiency has even been identified as direct cause of proximal tubule dysfunction.<a class="elsevierStyleCrossRef" href="#bib0365"><span class="elsevierStyleSup">35</span></a> The proximal tubule–proteinuria–vitamin D interaction, though speculative, could help explain these findings.</p><p id="par0245" class="elsevierStylePara elsevierViewall">The time of year the sample for 25(OH)D measurement is taken has been shown to influence the results in some studies.<a class="elsevierStyleCrossRefs" href="#bib0220"><span class="elsevierStyleSup">6,7</span></a> In very northern continental climates in the northern hemisphere, there is a huge difference between the cold seasons and the hot seasons in terms of the amount of sunlight. In contrast, the climate in Extremadura in Spain is southern continental, with quite sunny winters, which encourage people to go out in the sun, clement springs and autumns, but very hot summers, when it is necessary to shelter from the sun. These aspects may help explain the lack of significant differences in 25(OH)D levels according to the time of year in our patients.</p><p id="par0250" class="elsevierStylePara elsevierViewall">In this study, we found no significant association between low levels of 25(OH)D and statins or ACE inhibitors and/or ARAs. In another recent study<a class="elsevierStyleCrossRef" href="#bib0290"><span class="elsevierStyleSup">20</span></a> in a smaller group of patients with predialysis CKD and severe vitamin D deficiency, Yuste et al. found even lower 25(OH)D levels in those treated with statins, and higher levels in those treated with ACE inhibitors or ARAs. In the multivariate analysis of this study, however, the authors did not include proteinuria in the model fit, a fact that might have been of great interest for the interpretation of the results.</p><p id="par0255" class="elsevierStylePara elsevierViewall">In that same study,<a class="elsevierStyleCrossRef" href="#bib0290"><span class="elsevierStyleSup">20</span></a> Yuste et al. detected higher 25(OH)D levels in patients treated with allopurinol. In our study, treatment with XO inhibitors (allopurinol or febuxostat) was associated with higher levels of 25(OH)D compared to no such treatment, although this covariate narrowly missed being statistically significant in the multivariate analysis (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.05).</p><p id="par0260" class="elsevierStylePara elsevierViewall">There is a relationship between purine metabolism and vitamin D, with an inhibitory effect of uric acid and xanthine on 1-α-hydroxylase having been demonstrated.<a class="elsevierStyleCrossRefs" href="#bib0370"><span class="elsevierStyleSup">36–38</span></a> However, what role the inhibition of xanthine-oxidase may play in 25(OH)D metabolism is uncertain.</p><p id="par0265" class="elsevierStylePara elsevierViewall">The anti-inflammatory effect of XO inhibitors has been suggested as cause of the higher levels of 25(OH)D.<a class="elsevierStyleCrossRef" href="#bib0290"><span class="elsevierStyleSup">20</span></a> In our study, however, the 25(OH)D levels were not correlated with any inflammatory markers, such as C-reactive protein, and nor did those treated with XO inhibitors have lower C-reactive protein concentrations (data not shown). In contrast, we did find that patients treated with XO inhibitors had significantly less proteinuria than those not treated (1.39<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.38 vs. 2.13<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>2.46<span class="elsevierStyleHsp" style=""></span>g/g creatinine; <span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.005). The collinearity with proteinuria may therefore at least in part explain the association of treatment with XO inhibitors and 25(OH)D levels.</p><p id="par0270" class="elsevierStylePara elsevierViewall">This study has limitations, particularly in relation to the cross-over design, which prevents us from firmly establishing causal inferences.</p><p id="par0275" class="elsevierStylePara elsevierViewall">In conclusion, vitamin D deficiency is very common in CKD, and the magnitude of proteinuria is a factor with high relative importance in predicting reduced 25(OH)D levels. In view of the strong association with proteinuria, any study on the adverse effects of vitamin D deficiency in CKD (e.g. progression of renal failure) should take this relationship into account, since the magnitude of proteinuria and associated factors can also be very important as determinants of the clinical progression and prognosis of this disease.</p></span><span id="sec0040" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0110">Conflicts of interest</span><p id="par0280" class="elsevierStylePara elsevierViewall">The authors declare that they have no conflicts of interest.</p></span></span>" "textoCompletoSecciones" => array:1 [ "secciones" => array:10 [ 0 => array:3 [ "identificador" => "xres781993" "titulo" => "Abstract" "secciones" => array:5 [ 0 => array:2 [ "identificador" => "abst0005" "titulo" => "Introduction" ] 1 => array:2 [ "identificador" => "abst0010" "titulo" => "Aims" ] 2 => array:2 [ "identificador" => "abst0015" "titulo" => "Materials and methods" ] 3 => array:2 [ "identificador" => "abst0020" "titulo" => "Results" ] 4 => array:2 [ "identificador" => "abst0025" "titulo" => "Conclusions" ] ] ] 1 => array:2 [ "identificador" => "xpalclavsec781204" "titulo" => "Keywords" ] 2 => array:3 [ "identificador" => "xres781994" "titulo" => "Resumen" "secciones" => array:5 [ 0 => array:2 [ "identificador" => "abst0030" "titulo" => "Introducción" ] 1 => array:2 [ "identificador" => "abst0035" "titulo" => "Objetivos" ] 2 => array:2 [ "identificador" => "abst0040" "titulo" => "Material y métodos" ] 3 => array:2 [ "identificador" => "abst0045" "titulo" => "Resultados" ] 4 => array:2 [ "identificador" => "abst0050" "titulo" => "Conclusión" ] ] ] 3 => array:2 [ "identificador" => "xpalclavsec781205" "titulo" => "Palabras clave" ] 4 => array:2 [ "identificador" => "sec0005" "titulo" => "Introduction" ] 5 => array:3 [ "identificador" => "sec0010" "titulo" => "Materials and methods" "secciones" => array:3 [ 0 => array:2 [ "identificador" => "sec0015" "titulo" => "Patients" ] 1 => array:2 [ "identificador" => "sec0020" "titulo" => "Laboratory tests" ] 2 => array:2 [ "identificador" => "sec0025" "titulo" => "Statistical methods" ] ] ] 6 => array:2 [ "identificador" => "sec0030" "titulo" => "Results" ] 7 => array:2 [ "identificador" => "sec0035" "titulo" => "Discussion" ] 8 => array:2 [ "identificador" => "sec0040" "titulo" => "Conflicts of interest" ] 9 => array:1 [ "titulo" => "References" ] ] ] "pdfFichero" => "main.pdf" "tienePdf" => true "fechaRecibido" => "2015-09-21" "fechaAceptado" => "2016-01-13" "PalabrasClave" => array:2 [ "en" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Keywords" "identificador" => "xpalclavsec781204" "palabras" => array:3 [ 0 => "25-Hydroxy vitamin D" 1 => "Chronic kidney disease" 2 => "Proteinuria" ] ] ] "es" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Palabras clave" "identificador" => "xpalclavsec781205" "palabras" => array:3 [ 0 => "25-hidroxi-colecalciferol" 1 => "Enfermedad renal crónica" 2 => "Proteinuria" ] ] ] ] "tieneResumen" => true "resumen" => array:2 [ "en" => array:3 [ "titulo" => "Abstract" "resumen" => "<span id="abst0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0010">Introduction</span><p id="spar0005" class="elsevierStyleSimplePara elsevierViewall">The cause of vitamin D deficiency in chronic kidney disease (CKD) is probably multi-factorial; however, the relative importance of each potential determinant is uncertain.</p></span> <span id="abst0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0015">Aims</span><p id="spar0010" class="elsevierStyleSimplePara elsevierViewall">To determine factors associated with serum levels of 25-hydroxy vitamin D (25OHD) and their relative importance in a cohort of pre-dialysis CKD patients.</p></span> <span id="abst0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0020">Materials and methods</span><p id="spar0015" class="elsevierStyleSimplePara elsevierViewall">Incident patients admitted to a CKD outpatient clinic were included. Those who were receiving vitamin D supplements or anticonvulsants were excluded. In addition to demographic and clinical data, information about outdoor physical activity, season of blood collection, prescription of statins, anti-angiotensin drugs and xanthine-oxidase inhibitors were included as potential determinants. Johnson's relative weights analysis was used to estimate the relative importance of each potential determinant and the results were expressed as percentage contribution to multiple <span class="elsevierStyleItalic">R</span>.</p></span> <span id="abst0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0025">Results</span><p id="spar0020" class="elsevierStyleSimplePara elsevierViewall">The study group consisted of 397 patients, 30 of whom were excluded. The mean serum level of 25OHD was 13.7<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>7.4<span class="elsevierStyleHsp" style=""></span>ng/ml, and 81% of patients had serum levels lower than 20<span class="elsevierStyleHsp" style=""></span>ng/ml. By multiple linear regression and relative weights analyses, the best determinants of low serum 25OHD levels and their relative importance were: higher proteinuria (28.5%), old age (21.4%), low physical activity (19.4%), female gender (19.3%) and low serum bicarbonate levels (11.4%).</p></span> <span id="abst0025" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0030">Conclusions</span><p id="spar0025" class="elsevierStyleSimplePara elsevierViewall">Proteinuria and age are the determinants with the highest relative importance for predicting 25OHD levels in CKD patients.</p></span>" "secciones" => array:5 [ 0 => array:2 [ "identificador" => "abst0005" "titulo" => "Introduction" ] 1 => array:2 [ "identificador" => "abst0010" "titulo" => "Aims" ] 2 => array:2 [ "identificador" => "abst0015" "titulo" => "Materials and methods" ] 3 => array:2 [ "identificador" => "abst0020" "titulo" => "Results" ] 4 => array:2 [ "identificador" => "abst0025" "titulo" => "Conclusions" ] ] ] "es" => array:3 [ "titulo" => "Resumen" "resumen" => "<span id="abst0030" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0040">Introducción</span><p id="spar0030" class="elsevierStyleSimplePara elsevierViewall">El origen de la carencia de vitamina D en la enfermedad renal crónica (ERC) parece multifactorial, pero es incierta la importancia relativa de cada uno de sus potenciales determinantes.</p></span> <span id="abst0035" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0045">Objetivos</span><p id="spar0035" class="elsevierStyleSimplePara elsevierViewall">Determinar los factores asociados a los niveles de 25-hidroxi-colecalciferol (25OHD) y su importancia relativa en una cohorte de pacientes con ERC prediálisis.</p></span> <span id="abst0040" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0050">Material y métodos</span><p id="spar0040" class="elsevierStyleSimplePara elsevierViewall">Se incluyeron pacientes incidentes en una consulta de ERC, excluyendo a aquellos que recibían suplementos de vitamina D o anticonvulsivantes. Además de los datos demográficos y clínicos, se analizó la influencia de la actividad física, estación del año de la extracción, y tratamiento con estatinas, antiangiotensina e inhibidores de la xantino-oxidasa. Para la estimación de la importancia relativa se utilizó el método de ponderación relativa de Johnson, expresando los resultados como porcentajes de contribución al R múltiple.</p></span> <span id="abst0045" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0055">Resultados</span><p id="spar0045" class="elsevierStyleSimplePara elsevierViewall">Se estudiaron 397 pacientes, de los cuales 30 fueron excluidos. La concentración media de 25OHD fue de 13,7<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>7,4<span class="elsevierStyleHsp" style=""></span>ng/ml, presentando unos niveles inferiores a 20<span class="elsevierStyleHsp" style=""></span>ng/ml el 81% de los pacientes. Por regresión lineal múltiple y ponderación relativa, los principales determinantes de unos niveles más bajos de 25OHD fueron por orden de importancia: una mayor proteinuria (28,5%), mayor edad (21,4%), disminución de la actividad física (19,4%), sexo femenino (19,3%), y menor bicarbonato sérico (11,4%).</p></span> <span id="abst0050" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0060">Conclusión</span><p id="spar0050" class="elsevierStyleSimplePara elsevierViewall">La magnitud de la proteinuria y la edad son los factores con mayor importancia relativa como determinantes de los niveles de 25OHD en la ERC.</p></span>" "secciones" => array:5 [ 0 => array:2 [ "identificador" => "abst0030" "titulo" => "Introducción" ] 1 => array:2 [ "identificador" => "abst0035" "titulo" => "Objetivos" ] 2 => array:2 [ "identificador" => "abst0040" "titulo" => "Material y métodos" ] 3 => array:2 [ "identificador" => "abst0045" "titulo" => "Resultados" ] 4 => array:2 [ "identificador" => "abst0050" "titulo" => "Conclusión" ] ] ] ] "NotaPie" => array:1 [ 0 => array:2 [ "etiqueta" => "☆" "nota" => "<p class="elsevierStyleNotepara" id="npar0010">Please cite this article as: Caravaca-Fontán F, Gonzales-Candia B, Luna E, Caravaca F. Importancia relativa de los factores determinantes de los niveles séricos de 25-hidroxi-colecalciferol en la enfermedad renal crónica. Nefrologia. 2016;36:510–516.</p>" ] ] "multimedia" => array:3 [ 0 => array:7 [ "identificador" => "fig0005" "etiqueta" => "Fig. 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1046 "Ancho" => 1554 "Tamanyo" => 77927 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">Graph showing the percentage of patients with vitamin D deficiency (serum 25-hydroxycholecalciferol levels <15<span class="elsevierStyleHsp" style=""></span>ng/ml) according to predictive score based on age, gender, physical activity, proteinuria and serum bicarbonate. The total number of patients (<span class="elsevierStyleItalic">n</span>) in each scoring subgroup and the percentage with vitamin D deficiency are specified.</p>" ] ] 1 => array:8 [ "identificador" => "tbl0005" "etiqueta" => "Table 1" "tipo" => "MULTIMEDIATABLA" "mostrarFloat" => true "mostrarDisplay" => false "detalles" => array:1 [ 0 => array:3 [ "identificador" => "at1" "detalle" => "Table " "rol" => "short" ] ] "tabla" => array:1 [ "tablatextoimagen" => array:1 [ 0 => array:2 [ "tabla" => array:1 [ 0 => """ <table border="0" frame="\n \t\t\t\t\tvoid\n \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="table-head " align="" valign="top" scope="col" style="border-bottom: 2px solid black"> \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="" valign="top" scope="col" style="border-bottom: 2px solid black"> \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">25(OH)D deficiency \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">25(OH)D sufficiency \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black"><span class="elsevierStyleItalic">p</span> \t\t\t\t\t\t\n \t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Patients, <span class="elsevierStyleItalic">n</span> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">367 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">298 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">69 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Age (years) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">67<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>15 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">68<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>15 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">63<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>15 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.005 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Gender, males, <span class="elsevierStyleItalic">n</span> (%) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">193 (53) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">146 (49) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">47 (68) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.004 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Decrease in physical activity, <span class="elsevierStyleItalic">n</span> (%) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">157 (43) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">138 (46) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">19 (28) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.005 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Diabetes, <span class="elsevierStyleItalic">n</span> (%) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">149 (41) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">128 (43) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">21 (30) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.056 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Comorbidity index: no comorbidity/mild-to-moderate/severe, <span class="elsevierStyleItalic">n</span> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">97/212/58 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">68/180/50 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">29/32/8 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.005 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Body mass index (kg/m<span class="elsevierStyleSup">2</span>) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">30.1<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>5.9 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">30.3<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>5.9 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">29.1<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>5.7 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.146 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Serum 25(OH)D (ng/ml) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">13.7<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>7.4 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">10.95<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>4.11 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">25.83<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>5.95 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top"><0.0001 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Serum uric acid (mg/dl) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">7.2<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.8 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">7.2<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.8 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">6.9<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.8 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.166 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Serum bicarbonate (mEq/l) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">22.2<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>3.9 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">22.1<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>3.9 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">22.7<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>3.5 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.191 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Serum albumin (g/dl) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">4.04<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.36 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">4.02<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.36 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">4.15<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.34 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.006 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">C-reactive protein (mg/l) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">10.42<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>21.21 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">10.97<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>22.46 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">8.07<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>14.54 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.308 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Proteinuria (g/g creatinine) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">1.91<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>2.22 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">2.01<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>2.26 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">1.46<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.99 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.025 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Glomerular filtration rate (ml/min/1.73<span class="elsevierStyleHsp" style=""></span>m<span class="elsevierStyleSup">2</span>) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">14.9<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>5.1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">14.7<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>5.3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">15.8<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>3.6 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.098 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">XO inhibitors, <span class="elsevierStyleItalic">n</span> (%) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">109 (30) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">80 (27) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">29 (42) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.013 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Vitamin D analogs, <span class="elsevierStyleItalic">n</span> (%) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">54 (15) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">42 (14) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">12 (17) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.486 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">ACE inhib/ARA, <span class="elsevierStyleItalic">n</span> (%) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">307 (84) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">251 (84) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">56 (81) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.535 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Statins, <span class="elsevierStyleItalic">n</span> (%) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">209 (57) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">168 (56) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="left" valign="top">41 (59) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.645 \t\t\t\t\t\t\n \t\t\t\t</td></tr></tbody></table> """ ] "imagenFichero" => array:1 [ 0 => "xTab1299492.png" ] ] ] ] "descripcion" => array:1 [ "en" => "<p id="spar0060" class="elsevierStyleSimplePara elsevierViewall">Characteristics of the whole study group and subgroups according to whether they had serum levels of 25-hydroxycholecalciferol (25(OH)D) below (deficiency) or above (sufficiency) 20<span class="elsevierStyleHsp" style=""></span>ng/ml.</p>" ] ] 2 => array:8 [ "identificador" => "tbl0010" "etiqueta" => "Table 2" "tipo" => "MULTIMEDIATABLA" "mostrarFloat" => true "mostrarDisplay" => false "detalles" => array:1 [ 0 => array:3 [ "identificador" => "at2" "detalle" => "Table " "rol" => "short" ] ] "tabla" => array:3 [ "leyenda" => "<p id="spar0070" class="elsevierStyleSimplePara elsevierViewall">Multiple <span class="elsevierStyleItalic">R</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.356.</p><p id="spar0075" class="elsevierStyleSimplePara elsevierViewall">Variables that did not make the best prediction equation: time of year of extraction; comorbidity index (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>0.10); body mass index; eGFR; uric acid (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>0.10); albumin; C-reactive protein; diabetes; vitamin D analogs; ACE inhibitors/ARA; statins; and xanthine oxidase inhibitors (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.05).</p>" "tablatextoimagen" => array:1 [ 0 => array:2 [ "tabla" => array:1 [ 0 => """ <table border="0" frame="\n \t\t\t\t\tvoid\n \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="table-head " align="left" valign="top" scope="col" style="border-bottom: 2px solid black">Variable \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Beta \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Structure coefficient \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Relative importance<a class="elsevierStyleCrossRef" href="#tblfn0005"><span class="elsevierStyleSup">a</span></a> \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black"><span class="elsevierStyleItalic">p</span> \t\t\t\t\t\t\n \t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Age \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">−0.148 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">−0.528 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">21.4 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.006 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Gender \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.153 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.445 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">19.3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.002 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Decrease in physical activity \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">−0.124 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">−0.540 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">19.4 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.018 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Proteinuria \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">−0.194 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">−0.523 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">28.5 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top"><0.0001 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="table-entry ; entry_with_role_rowhead " align="left" valign="top">Serum bicarbonate \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.121 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.332 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">11.4 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="char" valign="top">0.020 \t\t\t\t\t\t\n \t\t\t\t</td></tr></tbody></table> """ ] "imagenFichero" => array:1 [ 0 => "xTab1299491.png" ] ] ] "notaPie" => array:1 [ 0 => array:3 [ "identificador" => "tblfn0005" "etiqueta" => "a" "nota" => "<p class="elsevierStyleNotepara" id="npar0005">Expressed as a percentage of contribution to multiple <span class="elsevierStyleItalic">R</span>.</p>" ] ] ] "descripcion" => array:1 [ "en" => "<p id="spar0065" class="elsevierStyleSimplePara elsevierViewall">Multiple linear regression and relative weighting. Factors best associated with 25(OH)D levels.</p>" ] ] ] "bibliografia" => array:2 [ "titulo" => "References" "seccion" => array:1 [ 0 => array:2 [ "identificador" => "bibs0005" "bibliografiaReferencia" => array:38 [ 0 => array:3 [ "identificador" => "bib0195" "etiqueta" => "1" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "25-Hydroxyvitamin D levels and the risk of mortality in the general population" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "M.L. Melamed" 1 => "E.D. Michos" 2 => "W. Post" 3 => "B. Astor" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1001/archinte.168.15.1629" "Revista" => array:6 [ "tituloSerie" => "Arch Intern Med" "fecha" => "2008" "volumen" => "168" "paginaInicial" => "1629" "paginaFinal" => "1637" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/18695076" "web" => "Medline" ] ] ] ] ] ] ] ] 1 => array:3 [ "identificador" => "bib0200" "etiqueta" => "2" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Vitamin D and multiple health outcomes: umbrella review of systematic reviews and meta-analyses of observational studies and randomised trials" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "E. Theodoratou" 1 => "I. Tzoulaki" 2 => "L. Zgaga" 3 => "J.P. Ioannidis" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "BMJ" "fecha" => "2014" "volumen" => "348" "paginaInicial" => "g2035" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/24690624" "web" => "Medline" ] ] ] ] ] ] ] ] 2 => array:3 [ "identificador" => "bib0205" "etiqueta" => "3" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Características del metabolismo óseo y mineral en pacientes con enfermedad renal crónica en estadios 3-5 no en diálisis: resultados del estudio OSERCE" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "J.L. Górriz" 1 => "P. Molina" 2 => "J. Bover" 3 => "G. Barril" 4 => "A.L. Martín-de Francisco" 5 => "F. Caravaca" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "Nefrología" "fecha" => "2013" "volumen" => "33" "paginaInicial" => "46" "paginaFinal" => "60" ] ] ] ] ] ] 3 => array:3 [ "identificador" => "bib0210" "etiqueta" => "4" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Vitamin D insufficiency and deficiency in chronic kidney disease. A single center observational study" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "E.A. González" 1 => "A. Sachdeva" 2 => "D.A. Oliver" 3 => "K.J. Martin" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1159/000081023" "Revista" => array:6 [ "tituloSerie" => "Am J Nephrol" "fecha" => "2004" "volumen" => "24" "paginaInicial" => "503" "paginaFinal" => "510" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/15452403" "web" => "Medline" ] ] ] ] ] ] ] ] 4 => array:3 [ "identificador" => "bib0215" "etiqueta" => "5" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Prevalence of vitamin D [25(OH)D] deficiency and effects of supplementation with ergocalciferol (vitamin D2) in stage 5 chronic kidney disease patients" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "D. Blair" 1 => "L. Byham-Gray" 2 => "E. Lewis" 3 => "S. McCaffrey" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1053/j.jrn.2008.04.008" "Revista" => array:6 [ "tituloSerie" => "J Ren Nutr" "fecha" => "2008" "volumen" => "18" "paginaInicial" => "375" "paginaFinal" => "382" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/18558303" "web" => "Medline" ] ] ] ] ] ] ] ] 5 => array:3 [ "identificador" => "bib0220" "etiqueta" => "6" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Prevalence of calcidiol deficiency in CKD: a cross-sectional study across latitudes in the United States" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "R.E. LaClair" 1 => "R.N. Hellman" 2 => "S.L. Karp" 3 => "M. Kraus" 4 => "S. Ofner" 5 => "Q. Li" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:7 [ "tituloSerie" => "Am J Kidney Dis" "fecha" => "2005" "volumen" => "45" "paginaInicial" => "1026" "paginaFinal" => "1033" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/15957131" "web" => "Medline" ] ] "itemHostRev" => array:3 [ "pii" => "S0735109710035503" "estado" => "S300" "issn" => "07351097" ] ] ] ] ] ] ] 6 => array:3 [ "identificador" => "bib0225" "etiqueta" => "7" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Clinical measures identify vitamin D deficiency in dialysis" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:5 [ 0 => "I. Bhan" 1 => "S.A. Burnett-Bowie" 2 => "J. Ye" 3 => "M. Tonelli" 4 => "R. Thadhani" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.2215/CJN.06440909" "Revista" => array:6 [ "tituloSerie" => "Clin J Am Soc Nephrol" "fecha" => "2010" "volumen" => "5" "paginaInicial" => "460" "paginaFinal" => "467" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/20185603" "web" => "Medline" ] ] ] ] ] ] ] ] 7 => array:3 [ "identificador" => "bib0230" "etiqueta" => "8" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Vitamin D levels and patient outcome in chronic kidney disease" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "P. Ravani" 1 => "F. Malberti" 2 => "G. Tripepi" 3 => "P. Pecchini" 4 => "S. Cutrupi" 5 => "P. Pizzini" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1038/ki.2008.501" "Revista" => array:6 [ "tituloSerie" => "Kidney Int" "fecha" => "2009" "volumen" => "75" "paginaInicial" => "88" "paginaFinal" => "95" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/18843258" "web" => "Medline" ] ] ] ] ] ] ] ] 8 => array:3 [ "identificador" => "bib0235" "etiqueta" => "9" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Vitamin D and UV exposure in chronic kidney disease" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "R. Krause" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "Dermatoendocrinology" "fecha" => "2013" "volumen" => "5" "paginaInicial" => "109" "paginaFinal" => "116" ] ] ] ] ] ] 9 => array:3 [ "identificador" => "bib0240" "etiqueta" => "10" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "A narrow-band ultraviolet B course improves vitamin D balance and alters cutaneous CYP27A1 and CYP27B1 mRNA expression levels in haemodialysis patients supplemented with oral vitamin D" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "M.J. Ala-Houhala" 1 => "K. Vähävihu" 2 => "E. Snellman" 3 => "T. Hasan" 4 => "H. Kautiainen" 5 => "P. Karisola" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1159/000355010" "Revista" => array:6 [ "tituloSerie" => "Nephron Clin Pract" "fecha" => "2013" "volumen" => "124" "paginaInicial" => "17" "paginaFinal" => "22" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/24029861" "web" => "Medline" ] ] ] ] ] ] ] ] 10 => array:3 [ "identificador" => "bib0245" "etiqueta" => "11" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Serum 25-hydroxyvitamin D level and diabetic nephropathy in patients with type 2 diabetes mellitus" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "Y. Peng" 1 => "L.J. Li" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1007/s11255-015-0983-3" "Revista" => array:7 [ "tituloSerie" => "Int Urol Nephrol" "fecha" => "2015" "volumen" => "47" "paginaInicial" => "983" "paginaFinal" => "989" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/25902763" "web" => "Medline" ] ] "itemHostRev" => array:3 [ "pii" => "S0735109711053538" "estado" => "S300" "issn" => "07351097" ] ] ] ] ] ] ] 11 => array:3 [ "identificador" => "bib0250" "etiqueta" => "12" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "The specific relationship between vitamin D deficiency and diabetic nephropathy among patients with advanced chronic kidney disease: a cross-sectional study in Gran Canaria, Spain" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "R.M. Sánchez-Hernández" 1 => "C. García-Cantón" 2 => "D.L. Lorenzo" 3 => "V. Quevedo" 4 => "E. Bosch" 5 => "L. López-Ríos" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Clin Nephrol" "fecha" => "2015" "volumen" => "83" "paginaInicial" => "218" "paginaFinal" => "224" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/25828886" "web" => "Medline" ] ] ] ] ] ] ] ] 12 => array:3 [ "identificador" => "bib0255" "etiqueta" => "13" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Low 25-hydroxyvitamin D levels and cognitive impairment in hemodialysis patients" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "K. Shaffi" 1 => "H. Tighiouart" 2 => "T. Scott" 3 => "K. Lou" 4 => "D. Drew" 5 => "D. Weiner" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.2215/CJN.10651012" "Revista" => array:6 [ "tituloSerie" => "Clin J Am Soc Nephrol" "fecha" => "2013" "volumen" => "8" "paginaInicial" => "979" "paginaFinal" => "986" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23449769" "web" => "Medline" ] ] ] ] ] ] ] ] 13 => array:3 [ "identificador" => "bib0260" "etiqueta" => "14" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Impaired vitamin D metabolism in CKD" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "C. Bosworth" 1 => "I.H. de Boer" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1016/j.semnephrol.2012.12.016" "Revista" => array:6 [ "tituloSerie" => "Semin Nephrol" "fecha" => "2013" "volumen" => "33" "paginaInicial" => "158" "paginaFinal" => "168" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23465502" "web" => "Medline" ] ] ] ] ] ] ] ] 14 => array:3 [ "identificador" => "bib0265" "etiqueta" => "15" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Fibroblast growth factor 23 and 25-hydroxyvitamin D levels are associated with estimated glomerular filtration rate decline" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "T. Hamano" 1 => "C. Nakano" 2 => "Y. Obi" 3 => "N. Fujii" 4 => "I. Matsui" 5 => "K. Tomida" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "Kidney Int Suppl" "fecha" => "2013" "volumen" => "3" "paginaInicial" => "469" "paginaFinal" => "475" ] ] ] ] ] ] 15 => array:3 [ "identificador" => "bib0270" "etiqueta" => "16" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Vitamin D insufficiency and deficiency with stages of chronic kidney disease in an Asian population" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:5 [ 0 => "B. Satirapoj" 1 => "P. Limwannata" 2 => "A. Chaiprasert" 3 => "O. Supasyndh" 4 => "P. Choovichian" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1186/1471-2369-14-206" "Revista" => array:5 [ "tituloSerie" => "BMC Nephrol" "fecha" => "2013" "volumen" => "14" "paginaInicial" => "206" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/24083392" "web" => "Medline" ] ] ] ] ] ] ] ] 16 => array:3 [ "identificador" => "bib0275" "etiqueta" => "17" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Serum 25-hydroxyvitamin D deficiency and the 5-year incidence of CKD" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "M.J. Damasiewicz" 1 => "D.J. Magliano" 2 => "R.M. Daly" 3 => "C. Gagnon" 4 => "Z.X. Lu" 5 => "K.A. Sikaris" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1053/j.ajkd.2013.03.010" "Revista" => array:7 [ "tituloSerie" => "Am J Kidney Dis" "fecha" => "2013" "volumen" => "62" "paginaInicial" => "58" "paginaFinal" => "66" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23623574" "web" => "Medline" ] ] "itemHostRev" => array:3 [ "pii" => "S0735109714025170" "estado" => "S300" "issn" => "07351097" ] ] ] ] ] ] ] 17 => array:3 [ "identificador" => "bib0280" "etiqueta" => "18" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "25-Hydroxyvitamin D levels and albuminuria in the Third National Health and Nutrition Examination Survey (NHANES III)" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:5 [ 0 => "I.H. De Boer" 1 => "G.N. Ioannou" 2 => "B. Kestenbaum" 3 => "J.D. Brunzell" 4 => "N.S. Weiss" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1053/j.ajkd.2007.04.015" "Revista" => array:6 [ "tituloSerie" => "Am J Kidney Dis" "fecha" => "2007" "volumen" => "50" "paginaInicial" => "69" "paginaFinal" => "77" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/17591526" "web" => "Medline" ] ] ] ] ] ] ] ] 18 => array:3 [ "identificador" => "bib0285" "etiqueta" => "19" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Impact of vitamin D on proteinuria, insulin resistance, and cardiovascular parameters in kidney transplant recipients" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "D.R. Lee" 1 => "J.M. Kong" 2 => "K.I. Cho" 3 => "L. Chan" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1016/j.transproceed.2011.08.081" "Revista" => array:6 [ "tituloSerie" => "Transplant Proc" "fecha" => "2011" "volumen" => "43" "paginaInicial" => "3723" "paginaFinal" => "3729" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/22172835" "web" => "Medline" ] ] ] ] ] ] ] ] 19 => array:3 [ "identificador" => "bib0290" "etiqueta" => "20" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "The effect of some medications given to CKD patients on vitamin D levels" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "C. Yuste" 1 => "B. Quiroga" 2 => "S.G. Vinuesa" 3 => "M.A. Goicoechea" 4 => "D. Barraca" 5 => "U. Verdalles" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "Nefrología" "fecha" => "2015" "volumen" => "35" "paginaInicial" => "150" "paginaFinal" => "156" ] ] ] ] ] ] 20 => array:3 [ "identificador" => "bib0295" "etiqueta" => "21" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Tools to support interpreting multiple regression in the face of multicollinearity" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:5 [ 0 => "A. Kraha" 1 => "H. Turner" 2 => "K. Nimon" 3 => "L.R. Zientek" 4 => "R.K. Henson" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.3389/fpsyg.2012.00044" "Revista" => array:5 [ "tituloSerie" => "Front Psychol" "fecha" => "2012" "volumen" => "3" "paginaInicial" => "44" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/22457655" "web" => "Medline" ] ] ] ] ] ] ] ] 21 => array:3 [ "identificador" => "bib0300" "etiqueta" => "22" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "A heuristic method for estimating the relative weight of predictor variables in multiple regression" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "J.W. Johnson" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1207/S15327906MBR3501_1" "Revista" => array:6 [ "tituloSerie" => "Multivariate Behav Res" "fecha" => "2000" "volumen" => "35" "paginaInicial" => "1" "paginaFinal" => "19" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/26777229" "web" => "Medline" ] ] ] ] ] ] ] ] 22 => array:3 [ "identificador" => "bib0305" "etiqueta" => "23" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "FIRE: an SPSS program for variable selection in multiple linear regression analysis via the relative importance of predictors" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "U. Lorenzo-Seva" 1 => "P.J. Ferrando" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.3758/s13428-010-0043-y" "Revista" => array:6 [ "tituloSerie" => "Behav Res Methods" "fecha" => "2011" "volumen" => "43" "paginaInicial" => "1" "paginaFinal" => "7" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/21287104" "web" => "Medline" ] ] ] ] ] ] ] ] 23 => array:3 [ "identificador" => "bib0310" "etiqueta" => "24" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Regression diagnostics: identifying influential data and sources of collinearity" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "D.A. Belsley" 1 => "E. Kuh" 2 => "R.E. Welsch" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:3 [ "fecha" => "1980" "editorial" => "John Wiley & Sons, Inc." "editorialLocalizacion" => "Hoboken, NJ, EE, UU" ] ] ] ] ] ] 24 => array:3 [ "identificador" => "bib0315" "etiqueta" => "25" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Vitamin D deficiency is common in children and adolescents with chronic kidney disease" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "H.J. Kalkwarf" 1 => "M.R. Denburg" 2 => "C.F. Strife" 3 => "B.S. Zemel" 4 => "D.L. Foerster" 5 => "R.J. Wetzsteon" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1038/ki.2011.431" "Revista" => array:7 [ "tituloSerie" => "Kidney Int" "fecha" => "2012" "volumen" => "81" "paginaInicial" => "690" "paginaFinal" => "697" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/22205356" "web" => "Medline" ] ] "itemHostRev" => array:3 [ "pii" => "S0735109715017829" "estado" => "S300" "issn" => "07351097" ] ] ] ] ] ] ] 25 => array:3 [ "identificador" => "bib0320" "etiqueta" => "26" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Serum 25-hydroxy vitamin D concentrations are more deficient/insufficient in peritoneal dialysis than haemodialysis patients in a sunny climate" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "K. Hanna" 1 => "R.G. Fassett" 2 => "E. Gill" 3 => "H. Healy" 4 => "M. Kimlin" 5 => "L. Ross" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1111/jhn.12234" "Revista" => array:6 [ "tituloSerie" => "J Hum Nutr Diet" "fecha" => "2015" "volumen" => "28" "paginaInicial" => "209" "paginaFinal" => "218" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/24720834" "web" => "Medline" ] ] ] ] ] ] ] ] 26 => array:3 [ "identificador" => "bib0325" "etiqueta" => "27" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Loss via peritoneal fluid as a factor for low 25(OH)D3 level in peritoneal dialysis patients" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:5 [ 0 => "G. Sahin" 1 => "I. Kirli" 2 => "B. Sirmagul" 3 => "E. Colak" 4 => "A.U. Yalcin" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1007/s11255-009-9561-x" "Revista" => array:6 [ "tituloSerie" => "Int Urol Nephrol" "fecha" => "2009" "volumen" => "41" "paginaInicial" => "989" "paginaFinal" => "996" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/19404765" "web" => "Medline" ] ] ] ] ] ] ] ] 27 => array:3 [ "identificador" => "bib0330" "etiqueta" => "28" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "The effect of cholecalciferol for lowering albuminuria in chronic kidney disease: a prospective controlled study" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "P. Molina" 1 => "J.L. Górriz" 2 => "M.D. Molina" 3 => "A. Peris" 4 => "S. Beltrán" 5 => "J. Kanter" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1093/ndt/gft360" "Revista" => array:6 [ "tituloSerie" => "Nephrol Dial Transplant" "fecha" => "2014" "volumen" => "29" "paginaInicial" => "97" "paginaFinal" => "109" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23975842" "web" => "Medline" ] ] ] ] ] ] ] ] 28 => array:3 [ "identificador" => "bib0335" "etiqueta" => "29" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Comparisons of serum vitamin D levels, status, and determinants in populations with and without chronic kidney disease not requiring renal dialysis: a 24-hour urine collection population-based study" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "I. Guessous" 1 => "W. McClellan" 2 => "D. Kleinbaum" 3 => "V. Vaccarino" 4 => "O. Zoller" 5 => "J.M. Theler" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1053/j.jrn.2014.04.005" "Revista" => array:6 [ "tituloSerie" => "J Ren Nutr" "fecha" => "2014" "volumen" => "24" "paginaInicial" => "303" "paginaFinal" => "312" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/25030223" "web" => "Medline" ] ] ] ] ] ] ] ] 29 => array:3 [ "identificador" => "bib0340" "etiqueta" => "30" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Effect of chronic metabolic acidosis on vitamin D metabolism in humans" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "J.A. Kraut" 1 => "E.M. Gordon" 2 => "J.C. Ransom" 3 => "R. Horst" 4 => "E. Slatopolsky" 5 => "J.W. Coburn" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Kidney Int" "fecha" => "1983" "volumen" => "24" "paginaInicial" => "644" "paginaFinal" => "648" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/6689348" "web" => "Medline" ] ] ] ] ] ] ] ] 30 => array:3 [ "identificador" => "bib0345" "etiqueta" => "31" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "The lack of effect of chronic metabolic acidosis on 25-OH-vitamin D metabolism and serum parathyroid hormone in humans" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "H.P. Weber" 1 => "R.W. Gray" 2 => "J.H. Dominguez" 3 => "J. Lemann Jr." ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1210/jcem-43-5-1047" "Revista" => array:6 [ "tituloSerie" => "J Clin Endocrinol Metab" "fecha" => "1976" "volumen" => "43" "paginaInicial" => "1047" "paginaFinal" => "1055" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/993311" "web" => "Medline" ] ] ] ] ] ] ] ] 31 => array:3 [ "identificador" => "bib0350" "etiqueta" => "32" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Vitamin D levels during and after resolution of ketoacidosis in children with new onset type 1 diabetes" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:6 [ 0 => "M.K. Singh" 1 => "N. Sachdeva" 2 => "S. Singhi" 3 => "S.V. Attri" 4 => "M. Jayashree" 5 => "A.K. Bhalla" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1111/dme.12200" "Revista" => array:6 [ "tituloSerie" => "Diabet Med" "fecha" => "2013" "volumen" => "30" "paginaInicial" => "829" "paginaFinal" => "834" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23692346" "web" => "Medline" ] ] ] ] ] ] ] ] 32 => array:3 [ "identificador" => "bib0355" "etiqueta" => "33" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Vitamin D status in children with intractable epilepsy, and impact of the ketogenic diet" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "A.G. Bergqvist" 1 => "J.I. Schall" 2 => "V.A. Stallings" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Epilepsia" "fecha" => "2007" "volumen" => "48" "paginaInicial" => "66" "paginaFinal" => "71" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/18330004" "web" => "Medline" ] ] ] ] ] ] ] ] 33 => array:3 [ "identificador" => "bib0360" "etiqueta" => "34" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Megalin and cubilin: synergistic endocytic receptors in renal proximal tubule" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "E.I. Christensen" 1 => "H. Birn" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:7 [ "tituloSerie" => "Am J Physiol Renal Physiol" "fecha" => "2001" "volumen" => "280" "paginaInicial" => "F562" "paginaFinal" => "F573" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/11249847" "web" => "Medline" ] ] "itemHostRev" => array:3 [ "pii" => "S0002914913009818" "estado" => "S300" "issn" => "00029149" ] ] ] ] ] ] ] 34 => array:3 [ "identificador" => "bib0365" "etiqueta" => "35" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Interactions of vitamin D and the proximal tubule" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "R.W. Chesney" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1007/s00467-015-3050-5" "Revista" => array:6 [ "tituloSerie" => "Pediatr Nephrol" "fecha" => "2016" "volumen" => "31" "paginaInicial" => "7" "paginaFinal" => "14" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/25618772" "web" => "Medline" ] ] ] ] ] ] ] ] 35 => array:3 [ "identificador" => "bib0370" "etiqueta" => "36" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Decreased serum concentrations of 1,25(OH)2-vitamin D3 in patients with gout" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:6 [ 0 => "S. Takahashi" 1 => "T. Yamamoto" 2 => "Y. Moriwaki" 3 => "Z. Tsutsumi" 4 => "J. Yamakita" 5 => "K. Higashino" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:7 [ "tituloSerie" => "Metabolism" "fecha" => "1998" "volumen" => "47" "paginaInicial" => "336" "paginaFinal" => "338" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/9500573" "web" => "Medline" ] ] "itemHostRev" => array:3 [ "pii" => "S0735109701013493" "estado" => "S300" "issn" => "07351097" ] ] ] ] ] ] ] 36 => array:3 [ "identificador" => "bib0375" "etiqueta" => "37" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Effect of uric acid on plasma levels of 1,25(OH)2D in renal failure" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "R. Vanholder" 1 => "S. Patel" 2 => "C.H. Hsu" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "J Am Soc Nephrol" "fecha" => "1993" "volumen" => "4" "paginaInicial" => "1035" "paginaFinal" => "1038" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/8286711" "web" => "Medline" ] ] ] ] ] ] ] ] 37 => array:3 [ "identificador" => "bib0380" "etiqueta" => "38" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Uric acid suppresses 1 alpha hydroxylase in vitro and in vivo" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "W. Chen" 1 => "C. Roncal-Jiménez" 2 => "M. Lanaspa" 3 => "S. Gerard" 4 => "M. Chonchol" 5 => "R.J. Johnson" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1016/j.metabol.2013.09.018" "Revista" => array:6 [ "tituloSerie" => "Metabolism" "fecha" => "2014" "volumen" => "63" "paginaInicial" => "150" "paginaFinal" => "160" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/24269076" "web" => "Medline" ] ] ] ] ] ] ] ] ] ] ] ] ] "idiomaDefecto" => "en" "url" => "/20132514/0000003600000005/v1_201612260003/S201325141630116X/v1_201612260003/en/main.assets" "Apartado" => array:4 [ "identificador" => "42660" "tipo" => "SECCION" "en" => array:2 [ "titulo" => "Original articles" "idiomaDefecto" => true ] "idiomaDefecto" => "en" ] "PDF" => "https://static.elsevier.es/multimedia/20132514/0000003600000005/v1_201612260003/S201325141630116X/v1_201612260003/en/main.pdf?idApp=UINPBA000064&text.app=https://revistanefrologia.com/" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S201325141630116X?idApp=UINPBA000064" ]
| Year/Month | Html | Total | |
|---|---|---|---|
| 2024 November | 3 | 4 | 7 |
| 2024 October | 45 | 61 | 106 |
| 2024 September | 31 | 35 | 66 |
| 2024 August | 55 | 53 | 108 |
| 2024 July | 35 | 23 | 58 |
| 2024 June | 65 | 35 | 100 |
| 2024 May | 54 | 28 | 82 |
| 2024 April | 72 | 36 | 108 |
| 2024 March | 50 | 28 | 78 |
| 2024 February | 41 | 31 | 72 |
| 2024 January | 31 | 16 | 47 |
| 2023 December | 36 | 29 | 65 |
| 2023 November | 40 | 36 | 76 |
| 2023 October | 53 | 41 | 94 |
| 2023 September | 33 | 27 | 60 |
| 2023 August | 56 | 24 | 80 |
| 2023 July | 42 | 24 | 66 |
| 2023 June | 43 | 16 | 59 |
| 2023 May | 62 | 24 | 86 |
| 2023 April | 44 | 10 | 54 |
| 2023 March | 82 | 23 | 105 |
| 2023 February | 43 | 17 | 60 |
| 2023 January | 51 | 24 | 75 |
| 2022 December | 76 | 27 | 103 |
| 2022 November | 71 | 29 | 100 |
| 2022 October | 73 | 43 | 116 |
| 2022 September | 50 | 31 | 81 |
| 2022 August | 72 | 43 | 115 |
| 2022 July | 56 | 44 | 100 |
| 2022 June | 53 | 43 | 96 |
| 2022 May | 90 | 23 | 113 |
| 2022 April | 80 | 52 | 132 |
| 2022 March | 82 | 54 | 136 |
| 2022 February | 73 | 35 | 108 |
| 2022 January | 90 | 31 | 121 |
| 2021 December | 72 | 34 | 106 |
| 2021 November | 55 | 39 | 94 |
| 2021 October | 100 | 42 | 142 |
| 2021 September | 64 | 26 | 90 |
| 2021 August | 76 | 56 | 132 |
| 2021 July | 65 | 28 | 93 |
| 2021 June | 49 | 30 | 79 |
| 2021 May | 80 | 54 | 134 |
| 2021 April | 153 | 53 | 206 |
| 2021 March | 88 | 45 | 133 |
| 2021 February | 83 | 12 | 95 |
| 2021 January | 74 | 21 | 95 |
| 2020 December | 81 | 26 | 107 |
| 2020 November | 58 | 17 | 75 |
| 2020 October | 52 | 24 | 76 |
| 2020 September | 55 | 29 | 84 |
| 2020 August | 58 | 16 | 74 |
| 2020 July | 62 | 10 | 72 |
| 2020 June | 58 | 10 | 68 |
| 2020 May | 70 | 13 | 83 |
| 2020 April | 79 | 32 | 111 |
| 2020 March | 65 | 15 | 80 |
| 2020 February | 64 | 27 | 91 |
| 2020 January | 89 | 16 | 105 |
| 2019 December | 146 | 16 | 162 |
| 2019 November | 147 | 40 | 187 |
| 2019 October | 176 | 24 | 200 |
| 2019 September | 181 | 18 | 199 |
| 2019 August | 143 | 18 | 161 |
| 2019 July | 99 | 32 | 131 |
| 2019 June | 91 | 29 | 120 |
| 2019 May | 110 | 32 | 142 |
| 2019 April | 125 | 30 | 155 |
| 2019 March | 69 | 35 | 104 |
| 2019 February | 41 | 26 | 67 |
| 2019 January | 46 | 27 | 73 |
| 2018 December | 208 | 44 | 252 |
| 2018 November | 313 | 12 | 325 |
| 2018 October | 230 | 16 | 246 |
| 2018 September | 161 | 10 | 171 |
| 2018 August | 119 | 16 | 135 |
| 2018 July | 59 | 15 | 74 |
| 2018 June | 54 | 16 | 70 |
| 2018 May | 63 | 16 | 79 |
| 2018 April | 64 | 11 | 75 |
| 2018 March | 53 | 9 | 62 |
| 2018 February | 133 | 5 | 138 |
| 2018 January | 225 | 10 | 235 |
| 2017 December | 146 | 5 | 151 |
| 2017 November | 77 | 18 | 95 |
| 2017 October | 47 | 6 | 53 |
| 2017 September | 46 | 11 | 57 |
| 2017 August | 27 | 6 | 33 |
| 2017 July | 31 | 3 | 34 |
| 2017 June | 58 | 9 | 67 |
| 2017 May | 41 | 7 | 48 |
| 2017 April | 42 | 5 | 47 |
| 2017 March | 24 | 4 | 28 |
| 2017 February | 25 | 6 | 31 |
| 2017 January | 30 | 7 | 37 |
| 2016 December | 20 | 3 | 23 |
Show all
