Twenty-five years ago this month, the New England Journal of Medicine published a special report on something that’s become medical gospel:
That’s right. Not as in “take two and call me in the morning,” but in the realm of the randomized double-blinded placebo-controlled trial. Or what we generally consider the gold standard of evidence in medical research.
If you’ve often heard that bit of jargon but always wondered why it’s so exalted, break it down:
- randomized: the assignment of the treatment (aspirin) or placebo (‘inert’ sugar pill) is not given in any planned sequence.
- double-blinded: neither the researchers nor the subjects know who is taking what (everything is coded so that analysts can find out at the end).
- placebo-controlled: the study compares the treatment against placebo to see if it’s helpful or harmful.
Even though acetylsalicylic acid’s properties as a pain reliever and fever reducer had been known in the time of Hippocrates, it was in 1899 that Bayer first patented and marketed what came to be known as aspirin worldwide.
A mere 89 years later, researchers from the “Physicians Health Study” did something unusual. Citing aspirin’s “extreme beneficial effects on non-fatal and fatal myocardial infarction”–doctor speak for heart attacks–the study’s Data Monitoring Board recommended terminating the aspirin portion of the study early (the study also was looking at the effects of beta-carotene). In other words, the benefit in preventing heart attacks was so clear at 5 years instead of the planned 12 years of study that it was deemed unethical to continue blinding participants or using placebo.
Turns out that aspirin inhibits platelets, tiny specialized blood cells whose job it is to stop your cuts from bleeding. In heart attacks, platelets clump inside the arteries of the heart depriving the heart muscle of vital oxygen. Using aspirin to inhibit their function is a key mechanism of preventing this phenomenon.
The amazing thing is that it took decades to organize an elegant and simple enough study with enough power (statistical heft) to show that good ol’ aspirin could really make a difference.
And that it was “just” aspirin. Shows how far we have yet to go in building medical knowledge.