Low-dose aspirin has been a staple of heart disease prevention for decades. However, although data have indicated that people taking aspirin are less likely to have heart attacks, they appear more likely to suffer from serious bleeding. Do the benefits of preventing heart attacks outweigh the risks of hemorrhage?
Does Aspirin Work for Preventing Heart Attacks?
New studies presented at the European Society of Cardiology suggest that the balance of benefit and risk might be too close to call for many people. In one of these trials, people at risk for a heart attack because they smoked or had high cholesterol or hypertension took 100 mg of aspirin or a look-alike placebo pill every day for about five years (The Lancet, Aug. 26, 2018). By the end of that time, 4.29 percent of those on aspirin had experienced a heart attack, stroke, unstable angina or death due to cardiovascular causes. That was slightly fewer than the 4.48 percent of people taking a placebo. On the other hand, more (0.97 percent) of the people on aspirin had a gastrointestinal bleed, compared to 0.46 percent of those on placebo. About the same proportion of people in each group experienced a serious adverse event, 20.19 percent on aspirin and 20.89 percent on placebo.
The investigators observed that there were far fewer heart attacks and strokes in both groups than they had anticipated. That means the trial really doesn’t tell us much, if anything, about how well aspirin works for people at moderate to high risk. Instead, it confirmed previous research that for people at low risk of a first heart attack, aspirin doesn’t provide enough benefit to make it worth the chance of a bleed.
Can People with Diabetes Take Aspirin for Preventing Heart Attacks?
The other trial included people with diabetes, a condition that puts them at higher risk for heart disease and strokes (New England Journal of Medicine, Aug. 26, 2018). More than 15,000 people in this randomized trial took aspirin or placebo. They also took either fish oil or an olive oil placebo. As a result, some people got both “active interventions,” some got one plus a placebo, and some got two placebos. The study lasted more than seven years.
The outcome: aspirin was helpful in preventing heart attacks and strokes, but it also triggered hemorrhages. About 4 percent of those taking it had a bleeding event. For comparison, approximately 3 percent of those taking placebo experienced a hemorrhage.
The investigators write:
“The absolute benefits were largely counterbalanced by the bleeding hazard.”
What Should You Do?
If you are currently taking low-dose aspirin (81 mg in the US) for preventing heart attacks, talk with your doctor. The two of you should consider your baseline risk for heart attacks and strokes. You will also want to evaluate your risk for a dangerous bleed. For most people at low risk of cardiovascular complications, aspirin may not be worthwhile. But those who are most susceptible to such problems may still benefit.
