Diabetes as a predictor of mortality in a cohort of blind subjects

There is only a little information about survival in newly registered blind subjects.

A closed cohort of blind subjects (n = 2680, 1803 of them women), newly registered between 1990 and 1993 in the district of Württemberg-Hohenzollern, Germany, was observed for up to 48 months. Mortality was compared to that of the general population. Predictors of mortality within that cohort were identified by Cox proportional hazards regression analysis.

Before 1 February 1994, 582 of the subjects had died. Diabetes had been diagnosed in 772 of the subjects, 226 of them died. The overall incidence rate of death was 12179 per 100,000 per year. The probability of survival after 47 months was 0.64 (95% confidence interval (CI): 0.59-0.70) in the non-diabetic, and 0.46 (95% CI: 0.37-0.55) in the diabetic subjects. Predictors of mortality in the regression model were age (risk ratio [RR] per year of age 1.047), sex (RR for men 1.247) and diabetes (RR when blindness was unrelated to diabetes: 1,448, RR when diabetes was the only cause of blindness: 2,253). Compared with the entire population, mortality was considerably increased in the blind cohort (comparative mortality figure [CMF] 4.79), particularly in individuals with diabetes (CMF = 6.55). The relative risks decreased with increasing age.

Overall mortality in this cohort was high, even higher than in previous studies on the mortality of the blind. Diabetes increased the risk of death. In addition, the cause of blindness in diabetic individuals was a major predictor of mortality.