November 30, 2021 -- Daily aspirin use is associated with an increased risk of new heart failure, a new analysis suggests.

Researchers found that among more than 30,000 patients who were at risk for developing heart failure, the risk for those taking daily aspirin was 26% higher than those not taking it over about 5 years of follow up.

The results though, don't apply to everyone, but only those with a high risk of heart failure or those already with some symptoms of heart failure, said senior investigator Jan A. Staessen, MD, PhD, professor emeritus at the University of Leuven in Belgium.

It's thought that heart failure is a condition that tends to create clots, and so in principle, patients should benefit from antiplatelet treatment like aspirin, which tends to decrease clot formation. However, findings from previous studies have been mixed on whether there is benefit from aspirin in these people, the researchers note.

This analysis included six observational studies, with a total of 30,827 participants. Overall, the rate of heart failure per 1,000 person-years for the entire population was 14.5 in the group on daily aspirin versus 5.9 in the group not taking aspirin.

Given the consistency of these results, "our observations suggest that aspirin should be prescribed with caution in patients at risk of HF or having HF," the investigators concluded.

"If such treatment is initiated in these patients, use low-dose aspirin," Staessen said.

However, Deepak L. Bhatt, MD, executive director of Interventional Cardiovascular Programs at Brigham and Women's Health inBoston, expressed some reluctance in applying this data to routine practice.

"It is important to emphasize that this pooled analysis draws upon six observational studies, not randomized trials of aspirin," Bhatt said, adding "to my knowledge, no such signal exists," in that data.

He called these findings "provocative," but he said they "would need to be confirmed in databases of already completed randomized trials of aspirin versus a control before being actionable."