Aspirin no longer beneficial in primary prevention of CVD and cancer: Study

Aspirin was first found to reduce the risk of fatal and nonfatal heart attacks 30 years ago, and subsequent studies found evidence that aspirin may also reduce the risk of stroke and colon cancer. Aspirin is one of the most commonly used medications and nearly half of adults 70 years and older have reported taking aspirin daily even if they don't have a history of heart disease or stroke.

A new paper published in Family Practice has revealed that a baby aspirin may no longer be recommended every day for primary prevention of a heart attack or stroke. Researchers concluded that aspirin no longer provides a net benefit as primary prevention for cardiovascular disease and cancer. The research has found that the widespread use of statins and cancer screening technology may have altered the benefits of aspirin use.

"We shouldn't just assume that everyone will benefit from low-dose aspirin, and in fact, the data show that the potential benefits are similar to the potential harms for most people who have not had a cardiovascular event and are taking it to try to prevent a first heart attack or stroke," said study author University of Georgia researcher Mark Ebell.

Most of these aspirin trials were set in Europe and the United States and recruited patients prior to 2000. Since then, cholesterol-lowering drugs have gone into widespread use, accompanied by better management of hypertension, less tobacco use, and widespread adoption of colorectal cancer screening.

Researchers compared these older studies with four recent large scale trials of aspirin. Broadly, participants in the newer trials resembled the contemporary population that would use aspirin for primary prevention. In comparison, they were older, somewhat less likely to smoke, and more likely to have type 2 diabetes than patients in the older trials.

Like older studies, the recent trials of aspirin for primary prevention found no mortality benefit and a significant increase in the risk of major haemorrhages. However, they failed to find evidence for the two important benefits of aspirin: a reduction in the risk of cancer deaths and a reduced risk of non-fatal heart attacks. For every 1000 patients who took aspirin for five years, there were four fewer major cardiovascular events but 7 more episodes of major haemorrhage and no change to overall cardiovascular mortality.

With the widespread use of statins and population-wide cancer screenings today, aspirin may no longer reduce the overall risk of cancer death or heart attack when given as primary prevention.

"The good news is that the incidence of cardiovascular disease and colorectal cancer are decreasing due to better control of risk factors and screening, but that also seems to reduce the potential benefit of aspirin."