From 2002 to 2012, the prevalence of stage 5 chronic kidney failure (CKD-5) has been persistently increasing, both in Catalonia and in Spain. In 2002, data from the Spanish Registry of Renal Patients (SRRP – Registro Español de Enfermos Renales), the Spanish Society of Nephrology (SSN – Sociedad Española de Nefrología) and the Spanish National Transplant Organisation (NTO – Organización Nacional de Trasplantes) showed an incidence of CKD stage 5 of 132 patients per million population (PMP), 94.4% of whom started renal replacement therapy (RRT), with haemodialysis (HD) as the first RRT; 4.6% started RRT with peritoneal dialysis (PD); and only 1% received an early renal transplantation (RT). The prevalence of CKD stage 5 in that year was 895 patients PMP.1 Incidence decreased to 120.4 patients PMP in 2012, but prevalence increased steadily, mainly due to the accumulation of patients who maintained a functioning RT.2 Data of year 2014 from the same registry, presented at the 45th SSN Conference in Valencia in October 2015, which included for the first time 100% of the population, showed that incidence was 133.6 patients PMP and the prevalence was 1179.3 patients PMP,3 for a Spanish population that at that time was 46,771,341 inhabitants.

In Catalonia the incidence of stage 5 CKD in 2002 was 146.8 PMP and the prevalence, 1017.8.4 Data from the Catalan Registry of Renal Patients (CRRP – Registre de Malalts Renals de Catalunya) for 2013 showed an incidence of 145.0 PMP and a prevalence of 1262.2.5

In Spain the annual cost of RRT for CKD stage 5 is more than 800 million euros. Although there are several estimates, this cost may represent up to 2.5% of the government's total annual health budget.6–9

Health care providers dealing with this disease, as well as patients themselves, face complex decisions such as, in most cases, making a decision of how the level of functional autonomy conditions the election the modality of RRT. Regarding RT, a risk–benefit analysis for patients has to be evaluated. And, of course, they must help to decide whether a patient should elect a conservative therapy.

All these decisions should be made by the patients themselves, with the help of health professionals, based on the best available evidence, and obviously, with the relevant family support, so that CKD patients are made aware of the risks and benefits of the different options used to treat their disease.

In the 1970s, Wennberg et al.10 studied the variations in health care service delivery. Since then, numerous studies have shown that place of residence may condition the number of hospitalisations, diagnostic tests or treatments, regardless of age, sex and the usual adjustment factors. Variations in health care delivery are matter of concern, because they indicate that some citizens receive less attention than they need, while others receive more and others receive care that they do not need,11 with a subsequent impact on both outcome indicators and health budgets that are limited. In Spain, as part of the “Atlas of Variations in Health Care Delivery in the National Health Service” project,12 and the one recently launched in Catalonia as part of this work,13 numerous studies have been conducted to analyse these variations for different diseases and procedures, although none have been dedicated to RRT. The study of RRT variations is of significant interest for patients and health care providers in terms of assessing whether the indications regarding the different RRT options—HD, PD or RT—are different according to geographic variability.

In a study of 31,778 patients at 56 sites in 13 regions of Canada, Sood et al.,14 adjusting the model by patient, site and region, it was found a variability in PD indication as the first RRT, with substantial differences in low indication (odds ratio 1.51; CI 95%: 1.33–1.73) versus high indication rates (odds ratio 0.69; CI 95%: 0.60–0.79), that were attributable to geographic region.

A few months later, these authors15 reported the findings on the study, extended to 33,263 patients and carried out between January 2001 and December 2010 at 63 sites in 14 different regions, also in Canada. Adjusting the model to type of patient and the dialysis centre, they found a variability in the indication of PD for RRT that was attributable in 96.9% of cases to the patient—case mix index—and in 3.1% of cases to the dialysis centre, with no variability in this study in relation to the region where the patients were included.

Couchaud et al.16 published data from the REIN registry. It was analysed the variability in PD indication in 10,815 incident cases from 59 districts in France and they compare, by using logistic regression models, factors such as age, gender, presence of diabetes, congestive heart failure, behavioural disorders, mobility and employment. PD was indicated in 14% of the incident cases, but with a large variability, from 0% to 45%, depending on the districts. The authors concluded that PD may be indicated in a wide array of different clinical conditions and that patients’ preferences play an important role in the choice of RRT method and therefore in this variability.

The aim of our study was to assess whether any variability in RRT indication might be due to inequity to the access or to other factors in different areas of health care in Catalonia.

Ecological study of variability in RRT by areas of health care. An ecological study is a type of epidemiological study, in which the unit of analysis is a set of individuals from a community that is well-defined geographically. Ecological studies allows to analyse the frequency of a disease.

The study's main source of data was the Catalan Transplant Organisation's (CTO) CRRP. From January 1, 2002 to December 31, 2012, incident cases on HD and PD per year were selected according to age (<45, 45–64 and ≥65 years) and gender. Given the low incidence of RT as the first RRT it was more appropriate to work with prevalent cases in the years 2005, 2009 and 2012. The denominator to calculate activity rate (the number of inhabitants of each area) was obtained from the Central Registry of Insured Persons of the Catalan Health Service (CatSalut), the public insurance.17 We also obtained from this source the structure by age group and gender group to calculate indirect standardisation.

The unit of analysis—i.e. the geographic areas—are the 45 areas of Heath Care Management from the 7 Health Care Regions of Catalonia. The areas of health care management are clusters of basic health care areas, which define regions formed by one or more hospitals and closely related basic health care areas. It is an intermediate level of organisation where primary and specialised care activities are coordinated.18

The outcome measures used in this study were the crude incidence rates of HD and PD by area (per 100,000 inhabitants). The standardised ratio of HD and PD incidence compare the interventions performed by the residents in an (observed) area with those that would have been performed (expected) if each of their age/gender groups had an utilisation to equal the whole set. Last, we analysed the prevalence of RT in 2005, 2009 and 2012 by area and by group of age and gender.

First the crude and standardised HD and PD rates were calculated by area and by groups of age and gender. Next, the usual statistics parameters of variability were estimated in an analysis of small areas19: the rate of variation between the 75th and 25th percentiles (RV 25–75), the systematic coefficient of variation (SCV) and the empirical Bayes (EB) approach. The SCV and EB are statistics parameters of variation that take into account the part of the variation that is expected for the type of phenomenon and population analysed. Both identify a source of variation between areas (which is expected to be systematic) and another source of variation within the area (which is expected to be at random). Although they usually use similar values, the EB is a better estimator than the SCV when the events in the areas are uncommon, as the EB corrects the effect of over-dispersion or extra-variation that tends to produce estimates of extreme systematic variation. For both statistics, the higher the value, the greater the systematic variation. By using a procedure with no systematic variation as a reference, such as a hip fracture, it has traditionally been agreed that values up to 0.05 involve no systematic variation; up to 0.10–20, moderate variation; and from 0.20, high variation. However, it is essential to put the value in a given context for each study.

Then, the standardised HD and PD ratios were constructed, which were described by using dot charts—in which each area is represented by a dot—and one map for each health area. All the analyses were performed using STATA, v13.

Despite the increase in the incidence of PD as the first choice for RRT, there is an relatively low use of PD as compared with the most recent data from the Spanish registry3 and from the European Renal Association-European Dialysis & Transplant Association (ERA-EDTA).19

The indication of PD and early RT as the first RRT is more frequent in patients <45 years of age. In this age group, the incidence of PD is three times greater than in >65 years and it is 50% higher than in patients 45–65 years of age.

No significant region-related variability was observed in incident cases receiving HD as the first RRT option; the same can be said about RT. All this leads us to believe that in our entire community there is a balanced equity to access RRT.

However, it was observed region-related variability in the indication of PD. The areas of Lérida and Garrotxa (in Girona) show a higher incidence of PD as compared with the median incidence in Catalonia.

Similar results have been observed in other countries where the use of HD and PD may show region-related variations, which seem to be related to the development of specific programmes by Nephrology Services.11 We believe that similarly to what has been observed in other countries the variability in the use of the different modalities of RRT, specific programmes generated by the nephrologist are making a difference. Other factors such as associated comorbidities or patients’ age, or even the organisational model of care or the ownership of the centres do not explain the region-related variations. All centres that offer HD are either publicly or private. The centres that perform RT are public. The centres that offer PD are public, but agreements are made with suppliers that provide the materials needed to perform PD, either continuous ambulatory peritoneal dialysis (CAPD) or automated peritoneal dialysis (APD).

To reduce the region-related variability in PD, it would be advisable to increase its indication in the rest of the areas so the PD reach levels similar to Lérida and Garrotxa in Girona.

To reach such objective, several aspects should be improved. First, it is necessary to develop or refine existing support tools that help to make shared decision about the most suitable choice of RRT. This decision has to be shared by the various actors—doctors, nurses, health officials—and the patients themselves and their families. It is important to consider the patients’ preferences, and to maintain and improve their quality of life as much as possible. The patients must have access to objective, regulated, understandable and detailed information on the different methods of RRT; this is essential when deciding on the RRT method. An informed and reasoned choice made by patients must be a fundamental element in the decision.

Second, further training of resident and fellows doctors should be enhanced, as well as maintaining and improving the ongoing training of health professionals working with CKD and PD, either in a centre itself or at centres with a PD programme. Third, the adoption of PD as the first RRT method should be promoted, with incentive-based reimbursement in contracts with different suppliers.

Finally, it would be desirable to analyse other potential types of region-related variability, such as the time needed to access the RT waiting list, or to analyse whether there are differences in access to RT depending on areas of residence. In Catalonia, the CTO is working in a comprehensive way to organise the proper management, uniformity and dissemination of all sources of information. This task will help to obtain data to evaluate and propose different actions and road maps.

In addition, the rates of patients >80 years in RRT have increased significantly in recent years.2,3,19 The current volume of cases is still insufficient to conduct a variability study in this population which will undoubtedly be of interest in future studies due to the fragility and complexity of this subgroup of patients.

Lastly, the results of this study may be affected by some limitations related to the quality of the data sources and by the usual limitations of the ecological design, limitations which affect the causality of the relationships observed and their transference to the individual level.20

In conclusion, there has been a notable increase in PD and early RT indications, but the rates for PD are still below the average for Spain and Europe. The variability is similar to that observed in other countries; it is worth to mention the regional variations in PD in Catalonia.

The authors declare that there are no conflicts of interest.