Improved long-term survival rate of chronic dialysis patients with diabetes mellitus

Abstract

Background. The survival rate of diabetic dialysis patients has been poor. However, it is uncertain whether the survival rate of these patients has been improving. Methods. Using the Okinawa Dialysis Study (OKIDS) registry, in which the records of all chronic dialysis patients in Okinawa, Japan, are filed, we compared the prognosis of dialysis patients with diabetes mellitus (DM) and that of dialysis patients with chronic glomerulonephritis (CGN). Using Cox proportional hazard analysis, we examined the effect of the start year of dialysis on survival after adjusting for confounding variables such as age, sex, and predialysis comorbid conditions. Results. Between 1976 and 1998, a total of 1256 DM patients and 2101 CGN patients started dialysis. In the DM patients who started dialysis between 1976 and 1990, the survival rate was 80.4% at 12 months and 42.1% at 60 months, and among those who started dialysis between 1991 and 1998, the survival rate was 87.9% at 12 months and 55.8% at 60 months. In both disease groups, the relative risk of death was significantly lower in patients who started dialysis between 1991 and 1998 than in those who started dialysis between 1976 and 1990. The adjusted relative risk (95% confidence interval [CI]) was 0.65 (95% CI 0.54–0.77). The relative risk of death of DM to CGN was 2.23 (95% CI, 1.91–2.60) when comparing those treated between 1976 and 1990, and 2.00 (95% CI, 1.62–2.46) when comparing those treated between 1991 and 1998. Conclusions. While the prognosis of diabetic dialysis patients in both categories improved significantly with time, that of DM patients was still worse than that of CGN patients.