The power of drug compliance: Active ingredient or placebo

Key Points

In this study of approximately 4,000 men with coronary heart disease, the drug clofibrate was compared to placebo in a randomized, double-blind trial over a 5-year period. The 5-year mortality in the men treated with clofibrate was 20% compared to 20.9% in the patients given placebo. This differential was clearly insignificant, and the study concluded with a negative outcome for the medication.

Surprising discovery

Among those assigned to the clofibrate group, the poor adherers had significantly higher mortality rates (25%) than those of good adherers (15%). The results in the placebo group were amazingly similar. Those who complied with their prescriptions of dummy pills had a mortality rate of 15%, while the group of men who failed to regularly take the placebos had a mortality rate of 28%.

How can one explain the finding that patients taking "fake" medication, believing it to be a powerful new medication, would have a significantly lower mortality rate than the group of men who did not take the fake medication regularly?

The authors of the study could not come up with any explanation of the results and reported their confusion in the final discussion of the study. During the late 1970s, medical researchers generally considered the placebo effect to be medical legend, so they failed to consider this aspect in their conclusions.

Today we know, from recent studies and fMRI imaging, that placebos do affect the body and the brain physiologically.

The New England Journal of Medicine recognized the significance of this study in 1980 with an article entitled "Influence of adherence to treatment and response of cholesterol on mortality in the Coronary Drug Project." [NEJM, 1980,303:1038-1041.]

I believe that the skepticism of modern medicine toward the placebo effect has kept this study hidden in the shadows of medical research instead of giving it the attention it deserves.