Microalbuminuria and mortality in long-duration type 1 diabetes

Abstract

OBJECTIVE - Microalbuminuria is a recognized risk factor for increased mortality and renal failure in type 1 diabetes. Whether it remains a powerful predictor in patients with a long duration of type 1 diabetes is not known. We ascertained the prognostic significance of abnormal urinary albumin excretion in a cohort of patients with at least 30 years of type 1 diabetes. RESEARCH DESIGN AND METHODS - A total of 190 patients with a disease duration of type 1 diabetes of at least 30 years with baseline and 5 years of follow-up. RESULTS - At baseline 66% were normoalbuminuric, and at 5 years 11% of this cohort had died. Of the 22% who were microalbuminuric at baseline, 26% had died, and of the 8% with persistent proteinuria at baseline, 44% had died. Of the 4% with end-stage renal failure at baseline, 71% had died within 5 years. Death was attributable to a cardiovascular cause in two-thirds of the cases in all groups. CONCLUSIONS - Even in those with a long duration of type 1 diabetes, the presence of abnormal urinary excretion remains a powerful predictor of increased mortality.