Costs and outcomes associated with clopidogrel discontinuation in Medicare beneficiaries with acute coronary syndrome in the coverage gap

BACKGROUND: Current guidelines for acute coronary syndrome recommend clopidogrel for an optimal period of 12 months in order to reduce the risk of reinfarction and mortality. Premature clopidogrel discontinuation has been associated with higher rates of rehospitalization, coronary stent thrombosis, and mortality. No data exist regarding the effect of the Medicare Part D coverage gap on medical costs and outcomes in Medicare beneficiaries who discontinue their clopidogrel upon entering the coverage gap. METHODS: Beneficiaries with a Medicare Advantage plan in 2009 who had a diagnosis of acute coronary syndrome were taking clopidogrel 75 mg daily, and reached the gap in the same year representing the study sample. From this cohort, those who filled at least two prescriptions for clopidogrel (continued) versus those that did not (discontinued) while in the gap were compared with regard to outcomes related to acute coronary syndrome and expenditure 30 days after the last prescription was filled and during any time while in the gap. Descriptive and multivariate analyses were used to compare these differences. RESULTS: A total of 1365 beneficiaries with acute coronary syndrome met the inclusion criteria, of which 705 beneficiaries entered into the coverage gap, wherein 103 (14.6%) and 602 (85.4%) of beneficiaries discontinued and continued clopidogrel, respectively. Compared with those who continued clopidogrel during the gap, beneficiaries who discontinued clopidogrel showed a higher trend in the number of hospitalizations related to acute coronary syndrome and emergency room visits, albeit not statistically significant. Those who discontinued clopidogrel showed a higher mean adjusted cost per member per month in hospitalizations ($3604) related to acute coronary syndrome and outpatient visits ($1144) related to acute coronary syndrome and total medical costs ($5614), albeit not statistically significant. CONCLUSION: Medicare beneficiaries who face large out-of-pocket costs for clopidogrel while in the coverage gap and discontinue therapy may experience adverse events related to acute coronary syndrome.