OUTCOME WITH CALCIUM-CHANNEL ANTAGONISTS AFTER MYOCARDIAL-INFARCTION - A COMMUNITY-BASED STUDY

Objectives. We sought to estimate the risk of death and recurrent myoc ardial infarction associated with the use of calcium antagonists after myocardial infarction in a population-based cohort study. Background. Calcium antagonists are commonly prescribed after myocardial infarcti on, but their long-term effects are not well established. Methods. Pat ients 25 to 69 years old with a suspected myocardial infarction were i dentified and followed up through a community-based register of myocar dial infarction and cardiac death (part of the World Health Organizati on Monitoring Trends and Determinants in Cardiovascular Disease [MONIC A] Project in Newcastle, Australia). Data were collected by review of medical records, in-hospital interview and review of death certificate s. Results. From 1989 to 1993, 3,982 patients with a nonfatal suspecte d myocardial infarction were enrolled in the study. At hospital discha rge, 1,001 patients were treated with beta-adrenergic blocking agents, 923 with calcium antagonists, 711 with both beta-blockers and calcium antagonists and 1,346 with neither drug. Compared with patients given beta-blockers, patients given calcium antagonists were more likely to suffer myocardial infarction or cardiac death (adjusted relative risk [RR] 1.4, 95% confidence interval [CI] 1.0 to 1.9), cardiac death (RR 1.6, 95% CI 1.0 to 2.7) and death from all causes (RR 1.7, 95% CI 1.1 to 2.6). Compared with patients given neither beta-blockers nor calci um antagonists, patients given calcium antagonists were not at increas ed risk of myocardial infarction or cardiac death (RR 1.0, 95% CI 0.8 to 1.3), cardiac death (RR 0.9, 95% CI 0.6 to 1.2) or death from all c auses (RR 1.0, 95% CI 0.7 to 1.3). No excess in risk of myocardial inf arction or cardiac death was observed among patients taking verapamil (RR 0.9, 95% CI 0.6 to 1.6), diltiazem (RR 1.1, 95% CI 0.8 to 1.4) or nifedipine (RR 1.3, 95% CI 0.7 to 2.2) compared,vith patients taking n either calcium antagonists nor beta-blockers. Conclusions. These resul ts are consistent with randomized trial data showing benefit from beta blockers after myocardial infarction and no effect on the risk of rec urrent myocardial infarction and death with the use of calcium antagon ists. Comparisons between beta-blockers and calcium antagonists favor beta blockers because of the beneficial effects of beta-blockers and n ot because of adverse effects of calcium antagonists. (C) 1998 by the American College of Cardiology.