Cause-specific mortality in type 2 diabetes - The Verona Diabetes Study

OBJECTIVE - This population-based study, carried out in the framework of th e Verona Diabetes Study investigated mortality from specific causes in know n type 2 diabetic patients. RESEARCH DESIGN AND METHODS - A cohort of 7,148 known type 2 diabetic patie nts (3,366 men and 3,782 women) was identified on 31 December 1986 and foll owed up for 5 years (1987-1991). Underlying causes of death were obtained f rom death certificates and were coded according to the International Classi fication of Diseases, Ninth Revision. Cause-specific death rates of diabeti c subjects were compared with those of the inhabitants of Verona. By 31 Dec ember 1991, 1,550 diabetic subjects (744 men and 806 women) had died. RESULTS - The standardized mortality ratio (SMR) for all causes of death wa s 1.42 (9596 CI 1.35-1.50). The highest SMRs were for the following specifi c causes: diabetes (SMR 4.47 [3.91-5.10]), gastrointestinal diseases (1.83 [1.50-2.21])-particularly liver cirrhosis (2.52 [1.96-3.20])-and cardiovasc ular diseases (1.34 [1.23-1.44]), particularly cerebrovascular (1.48 [1.25- 1.73]) and ischemic heart diseases (1.41 [1.24-1.62]). A significantly high er than expected risk of mortality for cardiovascular causes was already pr esent in the first 5 years after diagnosis and decreased with age. Type 2 d iabetic patients treated with insulin had a higher risk of dying than those treated orally or by diet. CONCLUSIONS - The highest SMRs in the diabetic cohort were for diabetes and liver cirrhosis. The mortality risk for cardiovascular diseases, although significantly higher than expected, was much lower in Italian type 2 diabet ic patients than that reported for American patients. The evidence of an ea rly effect on mortality suggests that prevention, early diagnosis, and trea tment should be improved.