1 in 10 heart patients may be inappropriately prescribed aspirin

More than 10% of patients treated with aspirin therapy for primary cardiovascular disease prevention should probably not have been taking the medication, according to a study.

Researchers examined a nationwide sample of 68,808 patients receiving aspirin for primary cardiovascular disease prevention from the National Cardiovascular Disease Registry Practice Innovation and Clinical Excellence (PINNACLE) Registry. Researchers identified patients from 119 practices who were prescribed aspirin between January 2008 and June 2013, excluding patients receiving aspirin as secondary prevention due to history of cardiovascular disease.

By evaluating aspirin guidelines by the American Heart Association, the U.S. Preventative Services Task Force, and other organizations, researchers determined that the most conservative cutoff for appropriate aspirin use was a 10-year cardiovascular disease risk of 6%. Results appeared online at the Journal of the American College of Cardiology on Jan. 12.

The study found that 11.6% of the overall cohort (7,972 of 68,808) received aspirin inappropriately. There was significant practice-level variation in inappropriate use (range, 0% to 71.8%). The median rate ratio (MRR), a statistical method used to quantify the degree of variation between practices, was calculated. An MMR of 1.0 indicates no variation between practices, with higher numbers indicating a greater degree of practice-level variation. The MMR for the overall cohort was 1.63 (95% CI, 1.47 to 1.77). Results remained consistent after excluding 21,052 women age 65 years and older (inappropriate aspirin use, 15.2%; median practice-level inappropriate aspirin use, 13.8%; interquartile range, 8.2%; adjusted MRR, 1.61; 95% CI, 1.46 to 1.75) and after excluding patients with diabetes (inappropriate aspirin use, 13.9%; median practice-level inappropriate aspirin use, 12.4%; interquartile range, 7.6%; adjusted MRR, 1.55; 95% CI, 1.41 to 1.67).

Additionally, women were more frequently inappropriately prescribed aspirin, at nearly 17% compared to men at 5%; patients inappropriately receiving aspirin were, on average, 16 years younger than those receiving aspirin appropriately; and inappropriate aspirin use decreased from 14% in 2008 to 9% in 2013, the study found.

The authors noted that patients seeking care for primary prevention of cardiovascular disease (CVD) in a cardiology practice should be treated like patients seeking care for the same reason in a primary care practice, that is, assessed for 10-year CVD risk and prescribed appropriate therapy to mitigate that risk. They speculated “that cardiologists may be preconditioned to seeing patients with a high burden of CVD and thus have a low threshold to use aspirin for primary CVD prevention, which at times may be inappropriate.”

An accompanying editorial noted that, due to side effects, inappropriate use of aspirin should be avoided, especially in younger patient populations. “Major coronary events are reduced 18% by aspirin, but at the cost of an increase of 54% of major extracranial bleeding,” the editorial stated. “Each 2 major coronary events have shown to be prevented by prophylactic aspirin at the cost of 1 major extracranial bleed. Yet, primary prevention with aspirin is widely applied.”