Prevalence and progression of CRF in Iceland: A population-based study

Background The prevalence of end-stage renal disease (ESRD) is lower in Europe than in the United States. The purpose of this study was to examine whether this difference results from a lower prevalence or slower progression of chronic renal failure (CRF) in a European cohort. Methods: We studied 18,912 subjects (9,773 women, 9,139 men) aged 33 to 81 years who participated in the Reykjavik Study between 1967 and 1991. Subjects with serum creatinine (SCr) levels of 1.7 mg/dL (150 mumol/L) or greater were considered to have CRF. We determined the crude prevalence of CRF, as well as age-standardized prevalence for 5-year age groups, in individuals aged 30 to 79 years. Progression of CRF was defined as a decrease in estimated glomerular filtration rate greater than 1 mL/min/1.73 m(2)/y. Results: Of 49 individuals who had an SCr of 1.7 mg/dL (150 mumol/L) or greater at entry, 41 individuals (26 men, 15 women) had a persistent elevation in SCr levels. Thirty-four individuals had mild CRF (SCr, 1.7 to 2.8 mg/dL [150 to 250 mumol/L]), 6 individuals had moderate CRF (SCr, 2.8 to 5.6 mg/dL [250 to 500 mumol/L]), and 1 individual had ESRD. The crude prevalence of CRF was 0.22% (220/100,000); 0.15% among women and 0.28% among men. The age-standardized prevalence was 0.23% (95% confidence interval [CI], 0.04 to 0.42) for women and 0.42% (95% CI, 0.18 to 0.66) for men. Eighty-five percent of patients with CRF were 50 years or older. Twenty-seven subjects had progressive renal failure, 17 of whom progressed to ESRD during a median of 7 years (range, 3 to 21 years). Conclusion: The prevalence of CRF is markedly lower in Iceland than in the United States. Furthermore, 27% of subjects did not show progression of their renal failure. These factors may explain in part the difference in ESRD prevalence between European countries and the United States.