A greater chance of ACE inhibitor use was observed in association with anterior wall acute myocardial infarction (OR 2.92; 95% CI 1.78 to 4.79) versus any other location; presence of systemic arterial hypertension (OR 2.04; 95% CI 1.27 to 3.27) versus absence; presence of diabetes (OR 1.97; 95% CI 1.10 to 3.53) versus absence; and Killip class II or III on admission (OR 7.13; 95% CI 1.61 to 31.39) in relation to Killip I. There was a trend toward a smaller chance of ACE inhibitor use in Killip class IV on admission (OR 0.36; 95% CI 0.08 to 1.62) versus Killip I. This evidence concerns the gene ACE and diabetes mellitus.