Comparison of incidence, prevalence, treatment modality and mortality of patients undergoing replacement of renal function in five Spanish regions inthe period 1991-1996

yBackground: For the last-few years, the Spanish autonomous communities of Andalusia, Canary Islands, Catalonia, Valencia and the Basque Country have had regional registries of patients treated with dialysis and transplantati on. We compared the evolution of incidence and prevalence of ESRD treated w ith renal replacement therapy in those communities in the period from 1991 to 1996 tin the ( Canary islands, from 1994) Material and methods: All patients with end-stage renal disease undergoing renal replacement therapy from those communities were included. Results: Both the age-standardized incidence rate and the prevalence rate i ncreased in the five communities, but in 1996 the ratios of the age-adjuste d races between the community with the highest rates (Canary Islands) and t hat with the lowest ones (the Basque Country) were 1.6 for prevalence and 2 .5 for incidence. These differences were even higher in the extreme age gro ups. The crude rates of patients with diabetic nephropathy starting renal r eplacement therapy increased from II to 22 cases per million population in the five communities overall and in 1996 the community with the highest inc idence (Canary islands) had at least four-fold the incidence of the communi ty with the lowest incidence (the Basque Country). The crude rates of patie nts with functioning kidney transplants increased throughout the period but ranged from 222 cases per million population in Andalusia to 355 cases in the Basque Country in 1996. In patients treated with dialysis, the mortalit y rate ranged in 1996 from 89 cases per thousand in Andalusia to 142 in Cat alonia. Conclusions: In the studied period, there were striking differences among c ommunities in their standardized rates of incidence and prevalence, crude r ates of mortality and treatment modalities. These differences show a remark able variability in inclusion criteria and clinical practice between the co mmunities studied.