Abstract 14286: Comparison of Enteric Coated Aspirin With Plain Aspirin on Effectiveness and Safety in the ADAPTABLE Trial

Introduction: Many clinicians recommend enteric coated aspirin (EC-ASA) to decrease gastrointestinal bleeding (GIB) in secondary cardiovascular (CV) protection even though studies suggest decreased platelet inhibition with EC-ASA compared to uncoated “plain” formulations (P-ASA). ADAPTABLE was a large, pragmatic study, showing no difference in ischemic events or bleeding between 81-mg and 325-mg ASA and provides a large population to assess effectiveness and safety of EC-ASA versus P-ASA in CV patients. Methods: Participants (pts) from ADAPTABLE were re-grouped according to type and dose of reported ASA use at baseline. The primary effectiveness endpoint was the composite of myocardial infarction (MI), stroke, or death from any cause and the primary safety endpoint was major bleeding events (hospitalization for a bleeding event with use of a blood product or intracranial hemorrhage) analyzed between groups by ASA type and within groups by dose using multivariable Cox proportional hazards. Results: 15,076 pts were randomized to 81-mg or 325 -mg ASA were followed for a median of 26.2 months of whom 10,678 reported ASA type at baseline. Of pts reporting ASA type used, 69% used EC-ASA and were slightly older, more likely to be in the 81-mg cohort, be nonsmokers, have slightly more coronary artery disease, and have a slightly lower prior MI rate (Table). No other significant differences between the 2 cohorts were noted. There was no significant difference in the effectiveness or safety outcomes between the EC-ASA and P-ASA cohorts (Table). Within EC-ASA and P-ASA, ASA dose had no effect on effectiveness (interaction p = 0.41) or safety (interaction p = 0.07). Conclusion: Enteric coating did not significantly affect the primary effectiveness or safety endpoints in ADAPTABLE, regardless of ASA dose. More research is needed to confirm whether enteric coated aspirin formulations or newer formulations will improve ischemic and bleeding outcomes in patients with CV disease.