What do the new draft guidelines say about aspirin?

The new draft guidelines from the United States Preventive Services Task Force recommend adults between the ages of 50-59 take aspirin if they have at least a 10% 10-year risk of having a heart attack or stroke as measured by a risk calculator .

For people 60-69, the task force says there is less benefit compared to for those ages 50-59, but that aspirin should still be used as long as there is a low risk of bleeding as a side effect.

But for patients younger than 50 or older than 70, the task force decided there was not enough evidence to make a recommendation about using aspirin. This is a major departure from the 2009 recommendation, which suggested use in all adults between the ages of 45-79 with an elevated risk of a heart attack or stroke.

This change happened in part because of a push to make medical guidelines strictly evidence-based. Right now, there are no randomized trials comparing aspirin to placebo in adults older than 70 or younger than 50. Without evidence, you can’t have evidence-based recommendations.

Basing guidelines strictly on evidence makes sense, but clinical trials are rarely perfect, and recommendations on how to use drugs need to make sense to primary care providers in order to avoid confusion.