Cardiac events in 735 type 2 diabetic patients who underwent screening for unknown asymptomatic coronary heart disease: 5-year follow-up report from the Milan Study on Atherosclerosis and Diabetes (MiSAD).

OBJECTIVE

To report the cardiac events in type 2 diabetic outpatients screened for unknown asymptomatic coronary heart disease (CHD) and followed for 5 years.

RESEARCH DESIGN AND METHODS

During 1993, 925 subjects aged 40-65 years underwent an exercise treadmill test (ETT). If it was abnormal, the subjects then underwent an exercise scintigraphy. Of the 925 subjects, 735 were followed for 5 years and cardiac events were recorded.

RESULTS

At the entry of the study, 638 of the 735 followed subjects had normal ETT, 45 had abnormal ETT with normal scintigraphy, and 52 had abnormal ETT and abnormal scintigraphy. The 52 subjects with abnormal scintigraphy and ETT underwent a cardiological and diabetological follow-up; the subjects with just abnormal ETT had a diabetological follow-up only. During the follow-ups, 42 cardiac events occurred: 1 fatal myocardial infarction (MI), 20 nonfatal MIs, and 10 cases of angina in the 638 subjects with normal ETT; 1 fatal MI in the 45 subjects with normal scintigraphy; and 1 fatal MI and 9 cases of angina in the 52 subjects with abnormal scintigraphy. In these 52 subjects all cardiac events were significantly more frequent (chi(2) = 21.40, P < 0.0001) but the ratio of major (cardiac death and MI) to minor (angina) cardiac events was significantly lower (P = 0.002). Scintigraphy abnormality (hazard ratio 5.47; P < 0.001; 95% CI 2.43-12.29), diabetes duration (1.06; P = 0.021; 1.008-1.106), and diabetic retinopathy (2.371; P = 0.036; 1.059-5.307) were independent predictors of cardiac events on multivariate analysis.

CONCLUSIONS

The low ratio of major to minor cardiac events in the positive scintigraphy group may suggest, although it does not prove, that the screening program followed by appropriate management was effective for the reduction of risk of major cardiac events.