5.7.2. Data sources

The present review is based on a compilation of studies on the prevalence of CKD among children, adolescents and adults and on the data of the Registry of the European Renal Association - European Dialysis and Transplant Association (ERA-EDTA) that collects data in patients with ESRD on RRT. Available data on the prevalence of CKD (stages 1-5) in EU countries were summarised in presentations given at a recent convention on CKD in European countries made at the XLIV Congress of the ERA-EDTA (Barcelona, 21st - 24th June 2007) (Zoccali and DeJong, 2007)  and unpublished information for some EU countries was derived from these presentations. Trend data for CKD are very scarce.

In quite a number of EU Member States renal registries are able to provide complete and reliable individual patient data on the incidence and prevalence of RRT for ESRD to the ERA-EDTA Registry for international comparison. Other Member States, especially some larger ones, are not yet able to provide individual patient data covering their whole country  (France, Germany, Italy, Spain and Portugal).  Most new Member States as well as non Member States have renal registries in development that will only include complete patient data in another few years. These different stages of development of renal registries hampered comparisons across Member States and non Member States. On the other hand, the availability of individual patient data within one European ERA-EDTA Registry facilitated the comparisons as at least a large part of the data could be analysed using exactly the same methodology.

The ERA-EDTA Registry (http://www.era-edta-reg.org) collects individual and aggregated data from national and/or regional renal registries in Europe and countries bordering the Mediterranean Sea. The individual patient data are used for epidemiological analysis to calculate incidence, prevalence and patient survival. These are published in the Registry annual reports together with aggregated incidence and prevalence data that are received from other European countries. In addition, the Registry performs more focused studies using data from a segment of the catchment population with the aim of answering specific research questions. The resulting information may assist health authorities and health planners in the formulation of policies for the care of renal failure in the EU.

For this report incidence and prevalence data on RRT were used from 42 registries in 29  countries. National and regional renal registries including individual patient data collect at least the date of birth and gender of each patient starting RRT in their coverage area together with information on primary renal disease and the start date and type of RRT. During follow-up of the patients the changes in treatment and the date and cause of death are registered. Registries collecting aggregated data usually perform yearly surveys among their renal centres. As availability of data depended on the existence of national and regional renal registries and the completeness of the coverage of their countries, data on RRT over the period 1992-2005 are incomplete. Seven EU-15 Member States (Austria, Belgium, Denmark, Finland, Greece, Sweden and The Netherlands) were able to provide complete individual patient data for the whole country over the entire period and six EU-15 Member States (France, Germany, Italy, Portugal, Spain and UK) provided individual or aggregated data either over a shorter period or with incomplete coverage of their country. Nine additional EU-27 Member States (Bulgaria, Czech Republic, Estonia, Hungary, Latvia, Poland, Romania, Slovakia and Slovenia) and a number of non Member States were able to provide aggregated data over a shorter period. The data used for mortality analyses included patients who started RRT over the period 1996-2000 from 16 renal registries in 9 EU-15 Member States (Austria, Belgium, Denmark, Finland, Greece, Spain, Sweden, The Netherlands, UK) plus Iceland and Norway.