Real-World Use and Outcomes of Oral Antiplatelets Among Patients with Acute Coronary Syndrome: A Retrospective Cohort Study

BACKGROUND: Acute coronary syndrome (ACS)-related readmission is an important hospital quality measure. Medication management therapy, especially adherence to antiplatelet agents post discharge, could play an important role in reducing readmission rates. Newer agents such as ticagrelor and prasugrel have been shown, in randomized control trials, to have superior effectiveness to cardiovascular outcomes compared to clopidogrel, but they are more expensive and have more common adverse events such as bleeding and dyspnea. OBJECTIVE: We compared real-world readmission rates and adherence to antiplatelet agents among patients who initiated these agents post discharge. METHODS: This was a retrospective cohortstudy of patients with an index ACS-related hospitalization between 1 July 2017 and 31 December 2018. Using integrated pharmacy and medical claims data from a large national pharmacy benefits manager for commercially insured adults aged ≥ 18 years, we compared ACS-related readmission and medication adherence (as medication possession ratio (MPR)) among the three agents. ANOVA and logistic regression, controlling for demographics such as age, gender, and Charlson Comorbidity Index, were used to estimate any association between the agents and 365-day readmission rates. RESULTS: Of the 948 eligible patients, 86, 342, and 520 were initiated on prasugrel, ticagrelor, and clopidogrel (PTC), respectively. There were 4.7%, 5.3%, and 8.5% readmissions rates in the PTC cohorts, respectively, but these were not statistically significant in either the ANOVA or the logistic regression analyses. MPR was highest in the ticagrelor (88.1%) cohort, followed by the prasugrel (79.1%) and clopidogrel (76.4%) cohorts. CONCLUSION: Ticagrelor cohort had the highest medication adherence. Clopidogrel cohort had the highest readmission rate but the difference with the other cohorts was statistically insignificant.