Becattini C et al. – Aspirin reduced the risk of recurrence when given to patients with unprovoked venous thromboembolism who had discontinued anticoagulant treatment, with no apparent increase in the risk of major bleeding.

• In this multicenter, investigator–initiated, double–blind study, patients with first–ever unprovoked venous thromboembolism who had completed 6 to 18 months of oral anticoagulant treatment were randomly assigned to aspirin, 100 mg daily, or placebo for 2 years, with the option of extending the study treatment.
• The primary efficacy outcome was recurrence of venous thromboembolism, and major bleeding was the primary safety outcome.

• Venous thromboembolism recurred in 28 of the 205 patients who received aspirin and in 43 of the 197 patients who received placebo (6.6% vs. 11.2% per year; hazard ratio, 0.58; 95% confidence interval [CI], 0.36 to 0.93) (median study period, 24.6 months).
• During a median treatment period of 23.9 months, 23 patients taking aspirin and 39 taking placebo had a recurrence (5.9% vs. 11.0% per year; hazard ratio, 0.55; 95% CI, 0.33 to 0.92).
• One patient in each treatment group had a major bleeding episode.
• Adverse events were similar in the two groups.