The 1984 Tasmanian insulin treated diabetes mellitus prevalence cohort: An eight and a half year mortality follow-up investigation

Abstract

Total mortality and underlying cause of death were examined in a population-based prevalence cohort ( n = 1232) of Tasmanians with insulin-treated diabetes mellitus. Eight and a half years after the establishment of the registry, the cause of death based on death certificate information was determined for the overall cohort and for three clasification groups of insulin-treated diabetes: Group A — childhood-onset IDDM cases; Group B — adult-onset IDDM cases; and Group C — adult-onset insulin-treated NIDDM cases. A total of 378 deaths occurred, providing an overall SMR of 2.2 (95% CI 2.0–2.4) compared to the Tasmanian population. Diabetic females experienced a higher SMR (2.6, 95% CI 2.3–3.0) than diabetic males (1.9, 95% CI 1.6–2.2). The all-cause SMRs for the diabetic classification groups were 4.6 (95% CI 3.4–6.1) in Group A, 1.8 (95% CI 1.5–2.1) in Group B, and 2.2 (95% CI 1.9–2.6) in Group C. After adjusting for age, gender and duration of diabetes, the mortality in Group C was significantly higher compared to Group B (odds ratio 1.6, 95% CI 1.2–2.3). This study indicates that people with childhood-onset IDDM experience 4.6 times the death rate compared to the Tasmanian population and that the excess mortality is most pronounced in females.