THE RISK OF MYOCARDIAL-INFARCTION ASSOCIATED WITH ANTIHYPERTENSIVE DRUG THERAPIES

Objective.-To assess the association between first myocardial infarcti on and the use of antihypertensive agents. Design and Setting.-We cond ucted a population-based case-control study among enrollees of the Gro up Health Cooperative of Puget Sound (GHC). Patients and Methods.-Case s were hypertensive patients who sustained a first fatal or nonfatal m yocardial infarction from 1986 through 1993 among women and from 1989 through 1993 among men. Controls were a stratified random sample of hy pertensive GHC enrollees, frequency matched to the cases on age, sex, and calendar year, All 623 cases and 2032 controls had pharmacological ly treated hypertension. Data collection included a review of the ambu latory medical record and a brief telephone interview of consenting su rvivors. Antihypertensive therapy was assessed using the GHC's compute rized pharmacy database. Results.-The first analysis included only the 335 cases and 1395 controls initially free of cardiovascular disease. Compared with users of diuretics alone, the adjusted risk ratio of my ocardial infarction was increased by about 60% among users of calcium channel blockers with or without diuretics (risk ratio=1.62; 95% confi dence interval [CI], 1.11 to 2.34; P=.01). The second analysis was res tricted to 384 cases and 1108 controls who were taking either a calciu m channel blocker or a beta-blocker. Among these subjects, the use of calcium channel blockers compared with beta-blockers was associated wi th about a 60% increase in the adjusted risk of myocardial infarction (risk ratio=1.57; 95% CI, 1.21 to 2.04; P<.001). While high doses of b eta-blockers were associated with a decreased risk of myocardial infar ction (trend P=.04), high doses of calcium channel blockers were assoc iated with an increased risk (trend P<.01). Conclusions.-In this study of hypertensive patients, the use of short-acting calcium channel blo ckers, especially in high doses, was associated with an increased risk of myocardial infarction. Ongoing targe-scale clinical trials will as sess the effect of various antihypertensive therapies, including calci um channel blockers, on several important cardiovascular end points. U ntil these results are available, the findings of this study support t he current guidelines from the Joint National Committee on the Detecti on, Evaluation and Treatment of High Blood Pressure that recommend diu retics and beta-blockers as first-line agents unless contraindicated, unacceptable; or not tolerated.