Discussion
GI tract bleeding, bleeding
EVENTS, SECONDARY, ASCVD, BLEEDING
In this post hoc secondary analysis of ADAPTABLE, a large multicenter, pragmatic, randomized clinical trial, we evaluated the association of aspirin formulation (enteric-coated vs uncoated aspirin) with the effectiveness and safety of aspirin in secondary prevention of ASCVD. The results of this analysis did not show any difference in the effectiveness or safety outcomes analyzed by formulation of aspirin consumed regardless of the dose of aspirin participants were randomly assigned. While prior pharmacodynamic studiesDue to reduced aspirin bioavailability and the possibility of limited cardiovascular protection, the value of enteric-coated aspirin has been called into question during the last few decades. Cox et alAcid-reducing medications, such as proton pump inhibitors and histamine type 2 receptor antagonists, used to buffer aspirin within the stomach, have been shown to affect dissolution of the enteric formulations of aspirin by altering the pH, composition, and ionic strength in the stomach.In terms of the safety profile, enteric coating has been postulated to have better protection against GI tract bleeding and other major bleeding events.When major bleeding was evaluated within formulation cohorts, there was no association with aspirin dose among participants using uncoated aspirin and a small but significant association among patients using enteric-coated aspirin at 325 mg compared with 81 mg. The lack of bleeding difference in the participants using uncoated aspirin may account for the apparent lack of difference in major bleeding seen in the overall ADAPTABLE trial. The results of the present study for the enteric-coated aspirin cohort differed from those of other trials in which no difference in major bleeding was noted; however, in those trials, formulation of aspirin used was not mentioned.It has been proposed that the coadministration of ARM with enteric-coated aspirin would decrease the frequency of bleeding. However, we were unable to demonstrate a clinical interaction between ARM and the presence of enteric coating associated with either major bleeding or GI tract bleeding in this analysis.