Aspirin has been a mainstay in the treatment and prevention of cardiovascular disease for decades.
We know that in patients who have had a heart attack in the past aspirin prevents a second heart attack, and during a heart attack aspirin is life-saving. We also know that in patients with a prior stroke aspirin prevents further strokes. And in patients with symptomatic narrowing of the arteries, that is chest pressure with exertion (angina) or calf pain with walking (claudication), aspirin prevents strokes and heart attacks.
So on that solid base of evidence, doctors have extended aspirin therapy to many other patients who don’t fit the above criteria but have risk factors for heart attack and stroke, risk factors such as diabetes, smoking, high blood pressure and high cholesterol. Practice guidelines have been formed recommending aspirin for such patients, despite the lack of evidence that it helps them. I’ve urged many patients with diabetes, high blood pressure and high cholesterol to start taking daily aspirin.
Well, there’s nothing like a good study to show us that we’ve been doing the wrong thing. The British Medical Journal published a study this week in which 1276 patients with diabetes and mild, asymptomatic narrowing of the arteries were randomized to receive daily aspirin or placebo. They were followed for over 6 years to assess differences in the rates of heart attack, stroke, amputations and death. The surprising result was that the aspirin group did no better than the placebo group. Aspirin didn’t help.
(By the way, the study also randomized patients to receive antioxidants or placebo, and the antioxidants didn’t help either.)
So to summarize, aspirin should be taken by patients who have had a previous stroke or heart attack, or have symptoms of artery narrowing, such as angina, claudication, or a prior angioplasty or bypass surgery. Patients taking aspirin because of risk factors for heart disease who have no symptoms of artery narrowing (even though I urged some of you to start aspirin!) should stop.
(Thanks to my colleague and pal, Dr. Rubencio Quintana, for showing me the British Medical Journal article.)
British Medical Journal article: The prevention of progression of arterial disease and diabetes (POPADAD) trial: factorial randomised placebo controlled trial of aspirin and antioxidants in patients with diabetes and asymptomatic peripheral arterial disease
UPDATE: In a subsequent post I retracted my conclusions, offered some balance to the controversy and urged readers to talk to their doctors before changing their aspirin regimen.