Early mortality from the time of diagnosis of Type 2 diabetes: a 5-year prospective cohort study with a local age- and sex-matched comparison cohort

Abstract

Aims: To study patterns and predictors of early mortality in individuals with a new diagnosis of Type 2 diabetes, compared with a local age- and sex-matched comparison cohort.

Methods: A total of 736 individuals diagnosed with Type 2 diabetes between 1 May 1996 and 30 June 1998 and non-diabetic age- and sex-matched control subjects were studied. Follow-up was 5.25 years. Age- and gender-specific all-cause mortality odds ratios were calculated for the diabetic cohort compared with the non-diabetic comparator group. Mortality odds ratios were ascertained using conditional logistic regression.

Results: There were 147 deaths in the diabetic cohort [cardiovascular (42.2%), cancer (21.1%)]. Compared with the non-diabetic cohort, mortality odds more than doubled [odds ratio (OR) 2.47; 95% confidence interval (CI) 1.74, 3.49]. These increased odds were present in all age bands (including those aged > 75 years at diagnosis) for both cardiovascular and non-cardiovascular causes. In women, a new diagnosis of Type 2 diabetes was associated with a sevenfold increase in mortality odds in those aged 60-74 years (OR 7.00; 95% CI 2.09, 23.47).

Conclusions: Type 2 diabetes is associated with a 2.5-fold increase in the odds of mortality in both men and women over the first 5 years from diagnosis. Our data strongly support the contention that the mortality risk associated with Type 2 diabetes essentially exists from, or may even predate, the time of diagnosis.