Aspirin for primary CVD prevention called into question
MedWire News: Researchers have cautioned against the routine prescription of aspirin for primary prevention of cardiovascular disease (CVD), after their meta-analysis demonstrated that any benefit is offset by the increased risk for bleeding among patients without any history of the disease.
Further research, including studies involving more high-risk participants, is need to identify those patients for whom primary prevention with aspirin has a favorable risk-to-benefit ratio, report Sreenivasa Seshasai (St George's University of London, UK) and co-authors.
"In the absence of such information, a reappraisal of current guidelines appears to be warranted, particularly in countries where a large number of otherwise healthy adults are prescribed aspirin, since a significant proportion of them may develop bleeding complications," they say.
Seshasai and team reviewed nine randomized placebo-controlled trials that included over 100,000 participants and reported on CVD, nonvascular outcomes, or death.
During a mean follow-up period of 6 years, aspirin treatment reduced total CVD events (including myocardial infarction [MI], stroke, cerebrovascular disease, heart failure, and peripheral arterial disease) by 10%, at a number needed to treat of 120. This association was driven primarily by a reduction in nonfatal MI, write the authors.
On the other hand, there was no significant reduction in CVD death or cancer mortality.
However, there was a significant 31% increase in the risk for nontrivial bleeding events (fatal from any site, cerebrovascular or retinal, from hollow viscus, requiring hospitalization and/or transfusion, or major regardless of source), at a number needed to harm of 73.
There was significant heterogeneity between coronary heart disease and bleeding outcomes, which could not be accounted for by major demographic or participants characteristics, the authors note.
Writing in the Archives of Internal Medicine, the authors state that their study provides the "largest evidence to date regarding the wider effects of aspirin treatment in primary prevention."
They continue: "Despite important reductions in nonfatal MI, aspirin prophylaxis in people without prior CVD does not lead to reductions in either cardiovascular death or cancer mortality."
"Routine use of aspirin for primary prevention is not warranted and treatment decisions need to be considered on a case-by-case basis," Seshasai et al conclude in the Archives of Internal Medicine.
In a related commentary, editorialist Samia Mora (Harvard Medical School, Boston, Massachusetts, USA) acknowledges that the use of aspirin for secondary prevention is "efficacious and lifesaving" and recommends that it is routinely prescribed as recommended by guidelines.
However, she agrees that in patients with no prior CVD, "the benefit to risk ratio for aspirin should be carefully weighed."
By MedWire Reporters