BETA-BLOCKERS AND THE PRIMARY PREVENTION OF NONFATAL MYOCARDIAL-INFARCTION IN PATIENTS WITH HIGH BLOOD-PRESSURE

A population-based, case-control study was conducted to determine whether β blockers, used for the treatment of high blood pressure, prevent first events of coronary heart disease. All study subjects were health-maintenance organization enrollees with pharmacologically treated hypertension. Patients presented in 1982 to 1984 with new coronary heart disease, and control subjects were a probability sample of eligible hypertensive enrollees free of coronary heart disease. With the investigators blind to case-control status, the subjects' medical records were reviewed for other coronary risk factors, and the health-maintenance organization's computerized pharmacy database was used to ascertain the use of β blockers. A larger proportion of controls than cases were using β blockers. This difference was confined to the subgroup with nonfatal myocardial infarctions. For current use, the estimated relative risk for nonfatal myocardial infarction was 0.62 (95% confidence interval, 0.39 to 0.99). Among current users of β blockers, higher doses conferred greater protection. Past use and total lifetime intake of β blockers were only weakly associated with case-control status. The current use of β blockers may prevent first events of nonfatal myocardial infarction in patients with high blood pressure. © 1990.