Primary Prevention With Metoprolol in Patients With Hypertension

To the Editor.— The results of the Metoprolol Atherosclerosis Prevention in Hypertensives (MAPHY) Study, 1 showing lower mortality with metoprolol use compared with thiazide diuretic therapy, is concordant with many of our beliefs that thiazides are potentially harmful while β-blockers may be cardioprotective. The MAPHY Study, by Wikstrand et al, used neither a placebo group nor actuarial data. As such, three possibilities exist. β-Blockers may be mortality neutral while diuretics have increased mortality, β-blockers may be cardioprotective while diuretics are mortality neutral, or β-blockers are cardioprotective and diuretics have increased mortality. In a previous study by Morgan et al, 2 moderately hypertensive men were treated with either placebo, low-salt diet, high-dose thiazide, or β-blocker. When compared with actuarial data there were twice as many deaths than predicted in the diuretic-treated group and expected numbers of deaths in all other groups. In the study by Wikstrand et al it is clear