Lifetime Risk of Stage 3-5 CKD in a Community-Based Sample in Iceland

Background and objectives Lifetime risk estimates of CKD can be used effectively in public education campaigns. This study sought to estimate lifetime risk of incident CKD stage 3 and higher in Iceland for people without CKD by the age of 45 years. Design, setting, participants, & measurements This was a prospective cohort study with longitudinal creatinine measurements of residents in Reykjavik, Iceland, from 1967 to 2005. CKD was ascertained by two consecutive eGFR measurements <60 ml/min per 1.73 m(2), development of treated kidney failure, one eGFR <60ml/min per 1.73 m(2) if the participant died before the next evaluation, or one eGFR, <45 ml/min per 1.73 m(2) if it was the last eGFR. Results Mean follow-up was 25 (SD10) years. Of the study participants, 727 (19%) developed the outcome and 942 (24%) died first. By age 85 years, the lifetime risks for 45-year-old women and men without prevalent CKD were 35.8% (95% confidence interval [95% CI], 32.7 to 38.9) and 21.3% (95% CI, 18.7 to 23.8), respectively. Risk was higher in individuals with a lower eGFR, hypertension, and a higher body mass index. Lifetime risk for higher stages of CKD 3b and 4 were less common than stage 3a; by age 85 years, the lifetime risks for CKD stages 3a, 3b, and 4 in women were 38.5% (95% CI, 25.8 to 51.1), 19.4% (95% CI, 8.9 to 29.9), and 3.6% (95% CI, 2.2 to 5.0), respectively. Conclusions The lifetime risk of developing CKD stage 3 or higher is substantial, emphasizing the importance of strategies to prevent development of CKD throughout the course of life. Estimates are lower than reported using single estimates of GFR, emphasizing the importance of confirming estimates of reduced GFR in studies of CKD.