Impact of aspirin dose according to race in secondary prevention of atherosclerotic cardiovascular disease: a secondary analysis of the ADAPTABLE randomised controlled trial

Abstract

Objectives To evaluate whether the effectiveness and safety of low (81 mg daily) versus high-dose (325 mg daily) aspirin is consistent across races among patients with established atherosclerotic cardiovascular disease (ASCVD).Design A secondary analysis of the randomised controlled trial ADAPTABLE was performed.Setting The study was conducted in 40 centres and one health plan participating in the National Patient-Centred Clinical Research Network (PCORnet) in the USA.Participants Among 15 076 participants with established ASCVD, 14 096 had self-reported race available and were included in the analysis. Participants were divided according to self-reported race as Black (n=1311, 9.3%), White (n=11 990, 85.1%) or other race (n=795, 5.6%).Interventions Participants were randomised to open-label daily aspirin doses of 81 mg versus 325 mg in a 1:1 ratio for a median of 26.2 months.Primary and secondary outcomes measures The primary effectiveness endpoint was a composite of death from any cause, hospitalisation for myocardial infarction or hospitalisation for stroke. The primary safety endpoint was hospitalisation for bleeding requiring blood product transfusion.Results Estimated cumulative incidence of the primary effectiveness endpoint at median follow-up with the 81 mg and the 325 mg daily doses were 6.70% and 7.12% in White participants (adjusted HR: 1.00 [95% CI: 0.88 to 1.15]); 12.27% and 10.69% in Black participants (adjusted HR: 1.40 [95% CI: 1.02 to 1.93]); and 6.88% and 7.69% in other participants (adjusted HR: 0.86 [95% CI: 0.54 to 1.39]) (p-interaction=0.12), respectively. There was no significant interaction between self-reported race and assigned aspirin dose regarding the secondary effectiveness and the primary safety endpoints.Conclusion Race is not an effect modifier on the impact of aspirin dosing on effectiveness and safety in patients with established ASCVD. In clinical practice, treatment decisions regarding aspirin dose in secondary prevention of ASCVD should not be influenced by race.Trial registration number NCT02697916.