Sarcopenia, characterized by the progressive loss of muscle mass and strength, is highly prevalent in patients on peritoneal dialysis (PD), significantly affecting their quality of life (QoL). The SarQoL questionnaire, a newly validated tool for assessing the impact of sarcopenia on QoL, has never been evaluated in PD patients. This study aimed to explore its applicability and relevance in this population.
MethodsThirty-two adult PD patients were recruited. Sarcopenia risk was assessed using the SARC-F questionnaire, anthropometric measures (e.g., skinfold thickness, body composition), and functional tests (handgrip strength, 30s chair-stand test). Correlations with the SarQoL score were thus explored.
ResultsThe mean SarQoL score was 70.95±15.96, indicating a low to mildly impaired QoL related to sarcopenia. Patients on automated PD (APD) scored significantly higher than those on continuous ambulatory PD (CAPD; p<0.0001). Strong inverse relationships were observed between SarQoL and SARC-F scores (r=−0.77, p<0.0001) and age (r=−0.50, p=0.003). Additionally, the SarQoL score was correlated with diastolic blood pressure (r=0.50, p=0.003), serum albumin (r=0.47, p=0.006), diuresis (r=0.46, p=0.007), number of stands at the chair test (r=0.46, p=0.02), and body fat percentage (r=−0.34, p=0.05).
ConclusionThe SarQoL questionnaire may be useful for evaluating sarcopenia's impact on well-being in PD patients. Future studies are needed to confirm these findings in wider cohorts and to explore longitudinal changes in SarQoL scores in response to interventions.
La sarcopenia, caracterizada por la pérdida progresiva de masa y fuerza muscular, es altamente prevalente en los pacientes en diálisis peritoneal (DP) y afecta significativamente su calidad de vida (CV). El cuestionario SarQoL, una herramienta recientemente validada para evaluar el impacto de la sarcopenia en la CV, nunca ha sido evaluado en pacientes en DP. Este estudio tuvo como objetivo explorar su aplicabilidad y relevancia en esta población.
MétodosSe reclutaron treinta y dos pacientes adultos en DP. El riesgo de sarcopenia se evaluó mediante el cuestionario SARC-F, medidas antropométricas (p. ej., pliegues cutáneos, composición corporal) y pruebas funcionales (fuerza de prensión manual, test de levantarse de la silla en 30 segundos). Se analizaron las correlaciones con la puntuación del SarQoL.
ResultadosLa puntuación media del SarQoL fue de 70,95 ± 15,96, lo que indica una CV relacionada con la sarcopenia de baja a levemente deteriorada. Los pacientes en DP automatizada (DPA) obtuvieron puntuaciones significativamente más altas que aquellos en DP continua ambulatoria (DPCA; p < 0,0001). Se observaron fuertes relaciones inversas entre la puntuación SarQoL y el SARC-F (r = −0,77; p < 0,0001) y la edad (r = −0,50; p = 0,003). Además, la puntuación SarQoL se correlacionó con la presión arterial diastólica (r = 0,50; p = 0,003), la albúmina sérica (r = 0,47; p = 0,006), la diuresis (r = 0,46; p = 0,007), el número de repeticiones en el test de la silla (r = 0,46; p = 0,02) y el porcentaje de grasa corporal (r = −0,34; p = 0,05).
ConclusiónEl cuestionario SarQoL puede ser útil para evaluar el impacto de la sarcopenia en el bienestar de los pacientes en DP. Se necesitan estudios futuros para confirmar estos hallazgos en cohortes más amplias y explorar los cambios longitudinales en la puntuación SarQoL en respuesta a intervenciones.
Sarcopenia, a condition characterized by a gradual loss of muscle mass and strength, is highly prevalent in patients undergoing peritoneal dialysis (PD)1 and may contribute to frailty, recurrent hospitalizations, and reduced survival.2
The SarQoL (Sarcopenia Quality of Life) questionnaire is an increasingly employed tool for assessing the impact of sarcopenia on the quality of life3; however, despite being validated in different frail populations,4 its applicability in renal patients remains, to date, unexplored.
Reduced quality of life is common in PD patients, and sarcopenia itself may contribute by limiting physical functioning and autonomy, thereby inducing a dangerous vicious circle.5
In this pilot study, we tested, for the first time, the validity and relevance of the SarQoL questionnaire in a small PD cohort. This evaluation was conducted alongside a comprehensive assessment of sarcopenia risk to better understand how this tool performs in this particular setting.
Material and methodsPatient selectionForty-two consecutive patients aged 18 years or older followed at the University Hospitals of Ioannina and Thessaloniki (Greece) who were on chronic renal replacement therapy by continuous ambulatory peritoneal dialysis (CAPD) or automated peritoneal dialysis (APD), were screened for participation. Of the 42 patients screened, 10 were excluded based on the following exclusion criteria: dialysis vintage<6 months or switch from hemodialysis, active cancer, severe malnutrition or obesity, or any severe neurological, muscular, or skeletal disability. The local Ethics committees (Ethical committee of Thessaloniki and Ioannina, approval codes n.28/22-11-2023 and 53238/1.11.2023) approved the study protocol and all participants provided written informed consent.
Sarcopenia risk screeningBefore beginning a scheduled outpatient visit, PD patients underwent a comprehensive anthropometric, clinical, and laboratory assessment. Patients’ screening for sarcopenia risk was first made by the SARC-F questionnaire.6 After completing this assessment, the patients were administered the SarQoL questionnaire, an instrument consisting of 22 questions, which include 53 distinct items covering physical functioning, mobility, fatigue, and the social limitations imposed by muscle loss.3 Most of these items are rated using a 3-, 4-, or 5-point Likert scale, while the rest are multiple-choice questions. The score ranges from 0 to 100, with 0 representing the worst possible quality of life and 100 indicating the best possible quality of life.
Additionally, patients underwent anthropometric analyses, including the measurement of skinfold thickness at the triceps (in women), pectoral (in men), abdominal/supra-iliac, and thigh level by a standard plicometer (Motivaly, Istanbul, Turkey). Lean and fat mass and body fat percentage were also estimated using the Jackson/Pollock and Siri equations.
Finally, upper and lower body muscle strength was evaluated by a standard handgrip test using an electronic hand dynamometer (Kuptone, Shenzhen, China) and by a 30-second Chair Stand Test (30SCT), respectively.
Statistical analysisThe statistical analysis was performed using the MedCalc Statistical Software (version 14.8.1; MedCalc Software bvba), and the GraphPad Prism software (version 9.0.0; GraphPad Software LLC).
Differences between groups were assessed by the unpaired t-test for normally distributed values. Correlations between clinical, dialysis, sarcopenia risk measures, and the SarQoL score were tested by the Pearson (R) coefficient. All results were considered statistically significant for p values≤0.05.
ResultsStudy populationThe final study population included 32 patients with an average age of 60.7±1.2 years. Twenty of them (62.5%) were male. Roughly half (14/32; 43.8%) had diabetes, and 12/32 (37.5%) reported a history of cardiovascular disease. Hypertension was highly prevalent (28/32; 87.5%). The media dialysis vintage media was 37±27 and 12/32 (37.5%) of patients were on continuous (CAPD) while the others were on automated (APD) peritoneal dialysis, with an average of 3.8±1.2 daily wells. The average ultrafiltration and urinary volumes were 700mL/day (787±492), and 1100mL/day (1039±608), respectively. The full characteristics of the study population are summarized in Table 1.
Main clinical parameters and sarcopenia risk measures recorded in the study population.
| Age (yrs) | 60.7±1.2 |
| Male gender (%) | 62.5 |
| Current smoking (%) | 6.3 |
| Diabetes (%) | 43.8 |
| History of CV disease (%) | 37.5 |
| Hypertension (%) | 87.5 |
| Cause of ESKD | |
| DKD (%) | 6.25 |
| Cardiorenal (%) | 21.9 |
| GNs (%) | 31.2 |
| Rare/ADPKD (%) | 18.7 |
| Other/Unknown (%) | 21.9 |
| Dialysis | |
| Dialysis vintage (mo.) | 37±27 |
| CAPD (%) | 37.5 |
| Daily wells (n.) | 3.8±1.2 |
| PET (%fast/average/slow) | 18.7/37.5/43.7 |
| Kt/V | 2.73±1.1 |
| UF (mL/day) | 787±492 |
| Diuresis (mL/day) | 1039±608 |
| Clinical/Lab | |
| Systolic BP (mmHg) | 134.5±20.3 |
| Diastolic BP (mmHg) | 79.3±12 |
| Serum Creatinine (mg/dL) | 6.1±2.5 |
| Urea (mg/dL) | 116.4±32.2 |
| Glycemia (mg/dL) | 96.8±37 |
| Albumin (g/dL) | 3.8±0.28 |
| Serum sodium (mmol/L) | 136.4±4 |
| Serum potassium (mmol/L) | 4.45±0.57 |
| Serum calcium (mg/dL) | 9.20±0.71 |
| Serum phosphate (mg/dL) | 4.89±1.23 |
| Red blood cells (n×106) | 4.14±1.2 |
| Hemoglobin (g/dL) | 11.7±1.1 |
| Platelets (n×103) | 255±64.2 |
| Total cholesterol (mg/dL) | 171±59.1 |
| LDL cholesterol (mg/dL) | 79 [62.2–118.2] |
| Triglycerides (mg/dL) | 157.4±66.3 |
| iPTH (pg/mL) | 205±93.4 |
CV, cardiovascular; DKD, diabetic kidney disease; GNs, glomerulonephritides, ADPKD, autosomal dominant polycystic kidney disease; CAPD, continuous ambulatory peritoneal dialysis; PET, peritoneal equilibration test; UF, ultrafiltration; BP, blood pressure; LDL, low-density lipoproteins; iPTH, intact parathormone.
The average SarQoL score was 70.95±15.96. APD patients displayed higher SarQoL scores than those on CAPD (p<0.0001); scores were also higher in individuals without previous history of CV disease (p=0.0009).
Median SARC-F values were 1.75 [IQR range 1–3]. Of note, only 5/32 patients had a SARC-F score suggestive of high sarcopenia risk (>4). Skinfold thickness was 40.9±15.7mm for the triceps, 32.1±10.5mm for the pectoral, 33.6±11.3mm for the supra-iliac, and 38.4±15.4mm for the thigh. The average body fat percentage was 35.2±10.4% with an estimated lean mass of 49.1kg±11.2 and fat mass of 26.5±8.8kg. The average grip strength was 23kg. The 30-second sit-to-stand test showed a mean of 10.4±3 repetitions. Finally, the average BMI was 26.5±3.3kg/m2 with a waist-hip ratio was 0.97±0.09. Table 1 displays the main sarcopenia risk measures.
Clinical and sarcopenia risk correlates of the SarQoL scoreAt correlation analyses (Fig. 1), the SarQoL score showed a strong inverse relationship with the SARC-F (r=−0.77, p<0.0001). Additionally, direct correlations were found with diastolic blood pressure (r=0.50, p=0.003), diuresis (r=0.46; p=0.007), serum albumin (r=0.47; p=0.006) and the number of stands at the 30-second Chair Stand Test (r=0.46, p=0.02), while inverse correlations were reported with age (r=−0.50, p=0.003), UF rate (r=−0.60, p=0.003), and body fat percentage (r=−0.34, p=0.05).
Discussion
This pilot study represents the first application of the SarQoL tool in PD patients. The average score reported in this cohort was 70.95±15.96, a result that aligns with those recorded in geriatric sarcopenic individuals with low to mildly impaired quality of life.7 Interestingly, APD patients displayed significantly higher SarQoL scores as compared to those on CAPD. This disparity could reflect differences in treatment modalities, with APD potentially offering advantages such as better preservation of residual renal function, more convenience, or lower systemic inflammation, all of which might contribute to improved physical and psychological well-being.8
Of note, a strong inverse relationship was observed between SarQoL and SARC-F scores (r=−0.77), indicating that patients with a higher risk of sarcopenia reported poorer quality of life. By the same token, lower SarQoL scores were associated with advanced age and hypoalbuminemia.
Aging is intrinsically linked to progressive muscle mass loss, reduced strength, and poorer physical function, which are further exacerbated in PD patients by the chronicity of kidney disease, dialysis-associated stress, social isolation, and the presence of comorbidities like cardiovascular diseases.9
Lower albumin levels often reflect chronic inflammation, protein-energy wasting, or inadequate dietary protein intake, all common in PD due to factors like reduced appetite, systemic inflammation, and protein losses in dialysate.10 These nutritional deficits directly contribute to muscle wasting and physical weakness, leading to functional impairment likely captured by the SarQoL questionnaire.
The comprehensive sarcopenia risk assessment made in our study adds depth to the interpretation of SarQoL scores. The observed inverse relationship between SarQoL and fat percentage, for instance, may reflect the detrimental effects of excess adiposity on physical function and metabolic health in PD patients. More importantly, the strong correlation between SarQoL and chair stand repetitions highlights the questionnaire's ability to reflect physical strength, suggesting its utility as a practical tool for evaluating functional outcomes.
ConclusionIn conclusion, the SarQoL questionnaire appears to be a promising tool for assessing sarcopenia related quality of life in peritoneal dialysis patients. Although novel, these observations remain preliminary and are limited by the small sample size, the observational design, the lack of objective confirmation of sarcopenia (such as bioimpedance analysis or muscle ultrasound), and the potential for selection bias. Therefore, larger studies in PD cohorts using additional validated objective measures are needed to fully validate our findings and confirm the utility of the SarQoL tool in this population.
Conflict of interestThe authors declare no conflict of interest.
