Improved incidence of end-stage renal disease of type 1 diabetes in Japan, from a hospital-based survey

OBJECTIVE: To explore whether the incidence of end-stage renal disease (ESRD) in type 1 diabetes (T1DM) was lowered over time, and how the baseline characteristics and risk factor management during follow-up were associated with the incident ESRD. RESEARCH DESIGN AND METHODS: An observational cohort study was performed in 1014 patients with T1DM diagnosed from 1961 to 1999, who were admitted to the diabetes center. The incidence of ESRD up to 2010 and the effect of risk factors, including annual mean glycated haemoglobin (HbA1c) and blood pressure, were investigated. RESULTS: During a mean follow-up of 19.3 years, with 88.3% follow-up rate, the incidence of ESRD was significantly lower in T1DM diagnosed in 1985–1999 than in 1961–1984 (0.8 vs 5.0 per 1000 person-years, p<0.0001), which was not precluded by preceding death. Multivariate Cox regression analysis indicated that the former group (vs the latter) was associated with a significantly reduced risk of ESRD independent of baseline variables of age, duration and gender (p<0.01). The continuous variable of year of T1DM diagnosis remained significant after adjustment for the above variables plus baseline proteinuria and retinopathy (p=0.02). Time-dependent Cox regression analysis indicated that ESRD was associated with annual mean HbA1c (p<0.01), systolic blood pressure (p<0.001) and baseline proteinuria (p<0.001), followed by continuous variable of year of T1DM diagnosis (p=0.09). CONCLUSIONS: Our data indicate that incidence of ESRD is decreasing over time, coinciding with enhanced glycemic and blood pressure controls. The incidence of ESRD in recently diagnosed T1DM appears to be much lower than previously reported ESRD incidence.