Application: Does Aspirin Help Prevent Heart Attacks? The Physician’s Health Study

Abstract

During the 1980s, approximately 22,000 physicians over the age of 40 agreed to participate in a long-term health study for which one important question was to determine whether or not aspiring helps to lower the rate of heart attacks (myocardial infarctions). The treatment for this part of the study was aspirin, and the controlwas a placebo. Physicians were randomly assigned to one treatment or the other as they entered the study so as to minimize bias caused by uncontrolled factors. The method of assignment was equivalent to tossing a coin and sending the physician to the aspirin arm of the study if a head appeared on the coin? After the assignment, neither the participating physicians nor the medical personnel who treated them knew who was taking aspirin and who was taking placebo. This is called a double-blind experiment. (Why is the double blinding important in a study such as this?) The method of measurement was to observe the physicians carefully for an extended period of time and record all heart attacks, as well as other problems, that might occur.

Source: “The final report on the aspirin component of the ongoing physicians’ health study,” The New England Journal of Medicine, 231(3) 1989, pp. 129-135.