Abstract
BACKGROUND: Kidney disease in patients with type 1 diabetes historically has been believed to be more prevalent in men. Because recent data do not reflect this pattern, we evaluated whether a sex difference persists. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: We used 18-year follow-up data from the Pittsburgh Epidemiology of Diabetes Complications Study (n = 788; baseline mean age, 27 years; diabetes duration, 19 years). PREDICTOR OR FACTOR: Sex and diagnosis interval (1950-1964 or 1965-1980). OUTCOMES: Cumulative incidences of macroalbuminuria (albumin excretion rate >200 μg/min) and end-stage renal disease (ESRD; kidney failure, dialysis, or transplant) were evaluated at 20, 25, and 30 years of diabetes duration. To address potential survival bias, death certificate information was included in determining ESRD for those who died before baseline (n = 145). Analyses were stratified by diagnosis year (1950-1964 or 1965-1980). OTHER MEASUREMENTS: Kidney disease risk factor information was available. RESULTS: A significant interaction was noted between sex and diagnosis cohort for ESRD incidence by 25 (P = 0.002) and 30 (P < 0.001) years' duration. Thus, within the 1950-1964 cohort (210 men and 180 women), ESRD incidence was higher in men compared with women by 25 (30.6% vs 18.0%, respectively) and 30 (43.4% vs 24.6%, respectively) years' duration of type 1 diabetes. However, in the 1965-1980 cohort (260 men and 283 women), the incidence was higher in women (7.6% vs 13.8% by 25 years [P = 0.04] and 13.7% vs 21.0% by 30 years' duration [P = 0.09] in men vs women, respectively). Results were similar for macroalbuminuria. LIMITATIONS: Study participants were not followed up from the onset of diabetes; thus, risk-factor data from that period are lacking. CONCLUSIONS: Our data suggest that the male excess of type 1 diabetic kidney disease cases observed in the earlier cohort has been eliminated in the younger cohort. The reason for this dramatic change presently is unclear, but should be addressed in subsequent studies.