Age-related differences in case-fatality rates among diabetic patients with myocardial infarction. Findings from National Hospital Discharge Survey, 1979-1987

Abstract

Objective: To determine age-related differences in case-fatality rates among diabetic patients with myocardial infarction (MI). Published studies have demonstrated 60% higher case-fatality rates during acute MI among diabetic patients compared with those without diabetes. However, many previous reports have been of insufficient size to examine the effect of age on mortality and have not been drawn from a representative sample of hospitals. The National Hospital Discharge Survey provides data on discharge diagnosis and vital status from a random sample of approximately 500 short-stay American hospitals.

Research design and methods: In this analysis, people with acute MI listed as the first diagnosis on the discharge sheet were studied. Any mention of diabetes mellitus on the discharge sheet was used to stratify the patients into those with and without diabetes.

Results: Age-adjusted case-fatality rates were identical in patients with and without diabetes for both sexes: 16.1 vs. 16.3 in men and 18 vs. 18.2 in women, respectively. Mortality rates were, however, higher among the younger patients with diabetes. Ratios of the case-fatality percentage by 10-yr age-groups (age 35-75 yr) and greater than or equal to 75 yr old for diabetes versus no diabetes were 1.7, 1.8, 1.2, 0.9, and 0.9 for men and 2.4, 1.2, 1.1, 1, and 0.9 for women.

Conclusions: Diabetes thus appears to increase the in-hospital mortality risk with acute MI disproportionately in the younger age-groups, particularly among men, and does not appear to be a marker of increased risk among the elderly.