Differences in discharge medication after acute myocardial infarction in patients with HMO and fee-for-service medical insurance

Abstract

Objective: To assess the impact of fee-for-service (FFS) versus HMO medical insurance coverage on receipt of aspirin, beta-blockers, and calcium channel blockers at the time of hospital discharge following an acute myocardial infarction.

Design: Prospective, population-based study.

Setting: All 16 community and tertiary care hospitals in the metropolitan area of Worcester, Massachusetts.

Patients: The study population consisted of patients under 65 years of age hospitalized with a validated acute myocardial infarction in all hospitals in the Worcester (Massachusetts) Standard Metropolitan Statistical Area (1990 census estimate, 437,000) during 1986, 1988, 1990, 1991, and 1993.

Measurements and main results: After adjustment for demographic and clinical variables as well as study year, the odds ratios for receipt of each medication for patients with HMO insurance compared with FFS were 1.05 (95% confidence interval [CI] 0.77, 1.44) for aspirin, 1.32 (95% CI 0.98, 1.76) for beta-blockers, and 0.72 (95% CI 0.54, 0.96) for calcium channel blockers. Examination of temporal trends in utilization of these agents suggests that observed decreases in use of calcium channel blockers and increases in use of beta-blockers over the period under study occurred more rapidly for HMO than for FFS patients.

Conclusions: Overall, use of aspirin and beta-blockers was comparable among HMO and FFS patients and use of calcium channel blockers (deemed less effective or ineffective for secondary prevention) was lower among HMO patients. Differential adoption, over time, of evidence-based prescribing practices for medications between HMO and FFS patients who have had a myocardial infarction warrants further study.