Incidence, prevalence, and mortality of diabetes in a large population. A report from the Skaraborg Diabetes Registry.

OBJECTIVE: Our objective was to analyze the prevalence, incidence, and mortality of diabetes in a population of 280,539 inhabitants. RESEARCH DESIGN AND METHODS: The incidence, prevalence, and deaths from diabetes at all ages of a population have been prospectively followed in the county of Skaraborg, Sweden, since 1991. RESULTS: The annual incidence of diabetes per 100,000 inhabitants in 1991-1995 was (mean +/- 95% CI) 14.7 +/- 3.2 for type 1 diabetes (diagnosed at 24.1 +/- 2.2 years of age) and 265.6 +/- 16.1 for type 2 diabetes (diagnosed at 66.6 +/- 0.6 years of age). The incidence of type 2 diabetes was significantly (P < 0.001) higher among men. There was no significant change in the age at diagnosis of diabetes. Although the incidence rate and the age at diagnosis were constant, the prevalence of diabetes increased by 6% each year. The relative mortality risk for diabetic patients was almost four times higher than expected. The median age at death, however, increased significantly, from 77.2 to 80.2 years (P < 0.05), during the study. CONCLUSIONS: The prevalence but not the incidence rate of diabetes increased during the years 1991-1995. Although diabetic patients showed a high relative mortality, increased survival apparently explains the increase in prevalence of diabetes in the country of Skaraborg.