I read with interest the recent editorial by Dr. Messerli [1]. As both a health services researcher-clinical epidemiologist and a practicing general internist, I have found the controversy about calcium channel blockers to be enlightening and frustrating. I strongly agree with Dr. Messerli that controlled studies documenting the safety and efficacy of calcium channel blockers are desperately needed. (It is interesting that such trials have not been done, and yet billions of dollars are spent each year prescribing and marketing these drugs.)

I do, however, disagree with two of his other statements. Messerli correctly states that case–control studies are subject to possible selection bias. This means that if physicians preferentially indicate that patients are at risk for death (presumably because of ischemic heart disease) with calcium channel blockers rather than with other antihypertensive agents, the increased rate of myocardial infarction may be caused by the indication, not the drug. He fails to mention, however, that Psaty and colleagues [2] have shown a clear dose-related decrease in the rate of myocardial infarctions among hypertensive patients receiving ß-blockers (despite a dose-related increase in the rate of myocardial infarction in hypertensive patients receiving calcium channel blockers). ß-blockers are subject to the same selection bias as are calcium channel blockers; however, patients at Group Health Cooperative of Puget Sound who take ß-blockers fare much better than do those who take calcium channel blockers.

Second, Messerli shows results for four placebo-controlled trials indicating that patients who receive long-acting calcium channel blockers survive longer than do patients who receive placebo. This finding is misleading in two ways. First, only one of the trials examined patients with hypertension. Psaty and colleagues did not contend that calcium channel blockers have no potential uses. They clearly state that these agents are associated with increased risk for myocardial infarction in patients with hypertension. Second, the comparison group in each of these studies received a placebo, but none of the Group Health patients in Psaty and colleagues' study did. Patients receiving calcium channel blockers had an increased risk for myocardial infarction compared with patients receiving other drugs. The take-home message from Psaty and colleagues' study was that the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure guidelines [3] should be followed: Hypertension should be initially treated with diuretics or ß-blockers, or both, and calcium channel blockers should be second- or third-line agents.