Undiagnosed diabetes mellitus among patients with prior myocardial infarction

To determine the prevalence of undiagnosed diabetic subjects in a group of long-term myocardial infarction (MI) survivors and to investigate their cardiovascular risk factors and medical care.

Glucose tolerance (OGTT WHO 1985), cardiovascular risk factors (blood pressure, lipids, urinary albumin), and primary medical care during the previous year were assessed among 244 patients without previously known diabetes (mean age +/- SD: 70.5 +/- 6.9 yrs; 75% males; time since incident infarction: 6.5 years (median), inter-quartile range: 4-9 years) from the population-based MONICA myocardial infarction registry in Augsburg (Germany).

Proportion of undiagnosed diabetes among MI registry patients was 29/244, 12% (95%CI: 8-17%); impaired glucose tolerance was found in 27% (22-34%). Using fasting glucose according to ADA 1997 criteria, 11% (7-16%) had diabetes and 17% (12-22%) impaired fasting glucose. MI registry patients with newly detected diabetes (WHO or ADA) showed a more adverse risk factor profile (higher triglycerides, lower HDL-cholesterol, increased urinary albumin) than subjects with normal glucose tolerance after controlling for possible confounders (age, sex, time since MI, antihypertensive and lipid-lowering medication). No significant differences were observed for self-reported medical care during the previous year among diabetic compared to non-diabetic subjects (number of physician visits and basic investigations).

There was a high prevalence of undiagnosed diabetes mellitus among the selected elderly long-term MI survivors. Because mortality rate after MI has been previously shown to be increased in diabetic patients, screening for glucose intolerance appears to be as essential as for standard cardiovascular risk factors.