Conventional risk factors reconsidered in patients with acute myocardial infarction.

Large-scale randomized clinical trials have allowed an exploration of the interactions between conventional risk factors and prognosis in patients who have already suffered acute myocardial infarction. The exposure to risk factors not only increases the probability of developing the disease but also affects the subsequent prognosis. Elderly, hypertensive and diabetic patients are at increased risk both during the in-hospital phase and afterwards. Nevertheless, secondary analyses sometimes produce unexpected results; the surprising finding of a protective effect of cigarette smoking with respect to death and re-infarction is probably the best example and illustrates how carefully secondary analyses should be performed.