Objective: In the population-based Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) cohort, we sought to examine whether a decline in the prevalence and incidence of end-stage renal disease (ESRD) was evident with increasing calendar year of type 1 diabetes diagnosis among people followed for 25 years. Factors associated with the hazard of incident ESRD that may mediate a decline were also investigated.
Research design and methods: Participants were examined at baseline in 1980 (n = 996) and at 4-25 years of follow-up. ESRD was defined by self-reported renal transplant or dialysis. Cumulative incidence with competing risk of death was determined. Incident ESRD was modeled by period of diagnosis, adjusting for other known risk factors using discrete time hazard models.
Results: When diabetes was diagnosed during 1970-1980, the unadjusted cumulative incidence of ESRD at 25 years was 9.3%. The unadjusted hazard of ESRD was reduced by 70% (P < 0.001), compared with those diagnosed with diabetes in 1922-1969; however, the association was attenuated by glycosylated hemoglobin level (HbA1c), systolic blood pressure, and antihypertensive use (hazard ratio [HR] 0.89 [95% CI 0.55-1.45]). HbA1c, age, and male sex remained associated with ESRD hazard after adjustment for kidney function and proliferative retinopathy.
Conclusions: A lower incidence of ESRD among those more recently diagnosed with type 1 diabetes was explained by improvements in glycemic and blood pressure control over the last several decades. Intensive diabetes management, especially for glycemic control, remains important even in long-standing diabetes as it may delay the development of ESRD.