Outcomes of inappropriate prescribing of β-blockers after an acute myocardial infarction in a medicaid population

BACKGROUND: Acute myocardial infarction (AMI) is associated with high mortality. β-Blockers are known to reduce mortality and reinfarction rates when used for long-term prevention following an AMI. OBJECTIVE: To assess the prescribing patterns of β-blockers in patients after experiencing an AMI in the West Virginia Medicaid program and examine its impact on patient outcomes. METHODS: One-year pre- and post-AMI data were extracted for 488 Medicaid patients. Prescribing of β-blockers within 90 days after discharge was evaluated among these patients. Based on American Heart Association/American College of Cardiology guidelines, patients were divided into 2 groups: those prescribed therapy appropriately and those prescribed therapy inappropriately (underuse, misuse). One-year all-cause mortality, cardiac mortality, and cardiac morbidity were compared between the groups using survival analysis. RESULTS: Approximately 64% of the patients were appropriately prescribed β-blockers and illustrated significantly (p = 0.035) lower all-cause mortality rates compared with the inappropriately prescribed group at the one-year follow-up. Cardiac mortality evaluation showed no significant findings. The groups differed significantly in morbidity outcome (time to first cardiac hospitalization), with the inappropriate group exhibiting later hospitalization at the end of the year (p = 0.019). However, the appropriate group had a higher proportion of hypertensive patients, suggesting more severity compared with the inappropriate group. CONCLUSIONS: Inappropriate prescribing of β-blockers following AMI was observed in this Medicaid population. Data suggest that there were overall survival benefits associated with appropriate β-blocker prescribing. However, cardiac morbidity associated with inappropriate prescribing needs to be evaluated after adjusting for disease severity between the 2 groups.