β-blocker compliance, mortality, and reinfarction: Validation of clinical trial association using insurer claims data

Although randomized controlled trials show that long-term β-blocker use post acute myocardial infarction (AMI) reduces mortality and subsequent cardiovascular events, and that increased compliance lowers mortality, there is limited published research on the effects of long-term β-blocker compliance in observational community settings. The authors retrospectively study the effect of β-blocker compliance on mortality and repeat reinfarction using claims records from a major health insurer of all patients who were discharged alive after AMI between January 2003 and June 2004, covered by that health insurer's prescription drug coverage, and prescribed β-blockers (n = 3923). Using Cox proportional hazards regressions, they estimate both survival and AMI-free survival rates by compliance quartile. Both survival and AMI-free survival rates diverge rapidly and are robust to adjustments for demographics, DxCG risk score, and other baseline risk factors. Results suggest that patients whose post-AMI compliance with β-blocker therapy is above average experience lower mortality and reinfarction. This is especially true for high-risk patients.