The effect of diabetes on incidence and mortality in end-stage renal disease in Germany

BACKGROUND: We aimed to examine the epidemiology and mortality risk of patients with incident end-stage renal disease (ESRD) in diabetic and non-diabetic individuals and to determine differences between sexes. METHODS: We used the claims data of a statutory health insurance company. Patients aged 30 years and older who started dialysis or had pre-emptive kidney transplantation between 1 April 2006 and 7 October 2008 were included. We estimated incidence rates of ESRD according to diabetes status, sex and age as well as relative and attributable risks due to diabetes. Using Cox regression, we studied survival and estimated time-dependent hazard ratios (HR). RESULTS: We included 623 patients with incident ESRD (n = 254 had diabetes); 477 (76.6%) were male, and the mean age was 66.5 years. Standardized to the German population, incidences of ESRD in patients with and without diabetes were 157.9 and 25.6 per 100,000 person-years respectively (6.2-fold increased risk). The impact of diabetes on mortality was time-dependent. Diabetics had an increased mortality risk after the first year. An interaction of diabetes with time (per additional year of follow-up) was found in the whole population (HR 2.01, 95% CI 1.21-3.33) and in females (HR 3.27, 95% CI 1.03-10.39); however, males did not reach statistical significance (HR 1.78, 95% CI 0.99-3.18). The fixed baseline effect of diabetes in these models was non-significant (HR ~ 0.7-0.8). CONCLUSIONS: Diabetes is an important risk factor for ESRD. We provide further evidence that the impact of diabetes on survival after ESRD is time-dependent and that differences between sexes might exist.