But results in significant reduction in rate of major vascular events, with improved net clinical benefit
MONDAY, Nov. 5 (HealthDay News) -- For patients with a first episode of unprovoked venous thromboembolism who complete initial anticoagulant therapy, aspirin does not reduce the recurrence of venous thromboembolism, but does correlate with a reduction in the rate of major vascular events, according to a study published online Nov. 4 in the New England Journal of Medicine to coincide with presentation at the American Heart Association's Scientific Sessions 2012, held from Nov. 3 to 7 in Los Angeles.
Timothy A. Brighton, M.B., B.S., from the Prince of Wales Hospital in Sydney, Australia, and colleagues conducted a randomized study involving 822 patients who had completed initial anticoagulant therapy after a first episode of unprovoked venous thromboembolism. Participants were allocated to receive 100 mg daily aspirin or placebo for up to four years.
During a median of 37.2 months of follow-up, the researchers found that the annual rate of recurrence was 6.5 percent in patients assigned to placebo versus 4.8 percent among those assigned to aspirin (hazard ratio for aspirin, 0.74; 95 percent confidence interval, 0.52 to 1.05; P = 0.09). Aspirin correlated with a reduction in the rate of two prespecified secondary composite outcomes: a 34 percent reduction in the rate of venous thromboembolism, myocardial infarction, stroke, or cardiovascular death (P = 0.01), and a 33 percent reduction in the rate of venous thromboembolism, myocardial infarction, stroke, major bleeding, or death from any cause (P = 0.01). The rates of major or clinically relevant non-major bleeding episodes or serious adverse events were not significantly different between the groups.
"These results substantiate earlier evidence of a therapeutic benefit of aspirin when it is given to patients after initial anticoagulant therapy for a first episode of unprovoked venous thromboembolism," the authors write.
Several authors disclosed financial ties to the pharmaceutical industry.