METHODS AND RESULTS: An individual patient data analysis of these trials was planned, before their results were known, to assess the effect of
aspirin versus placebo on recurrent VTE, major vascular events (recurrent VTE,
myocardial infarction,
stroke, and
cardiovascular disease death) and
bleeding, overall and within predefined subgroups. The primary analysis, for VTE, was by intention to treat using time-to-event data. Of 1224 patients, 193 had recurrent VTE over 30.4 months' median follow-up.
Aspirin reduced recurrent VTE (7.5%/yr versus 5.1%/yr; hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.51-0.90; P=0.008), including both
deep-vein thrombosis (HR, 0.66; 95% CI, 0.47-0.92; P=0.01) and
pulmonary embolism (HR, 0.66; 95% CI, 0.41-1.06; P=0.08).
Aspirin reduced major vascular events (8.7%/yr versus 5.7%/yr; HR, 0.66; 95% CI, 0.50-0.86; P=0.002). The major
bleeding rate was low (0.4%/yr for placebo and 0.5%/yr for
aspirin). After adjustment for treatment adherence, recurrent VTE was reduced by 42% (HR, 0.58; 95% CI, 0.40-0.85; P=0.005). Prespecified subgroup analyses indicate similar relative, but larger absolute, risk reductions in men and older patients.
CONCLUSIONS: www.anzctr.org.au. Unique identifier: ACTRN12611000684921.