Pharmaceutical Research

Prescription drug coverage does not assure long-term adherence to beta-blocker therapy following a heart attack

Taking beta-blockers for a sustained period of time after a heart attack improves survival and reduces the risk of another heart attack. Yet a new study found that less than half of heart attack patients regularly took beta-blockers during the first year after their heart attack. This predominantly young, working-age group had health insurance and prescription drug coverage. Thus, factors in addition to medication cost probably influenced their long-term adherence to beta-blocker therapy, according to researchers at the Duke Center for Education and Research on Therapeutics, which is supported by the Agency for Healthcare Research and Quality (HS10548).

Researchers examined claims records from members of 11 health plans, who had a heart attack in 2001, survived at least 1 year, and maintained insurance coverage. They defined patients as adherent to beta-blockers if they had prescription claims covering 75 percent or more days in the year after discharge from the hospital. They also examined the association of type of health plan, patient age group and sex, and other factors related to beta-blocker adherence.

During the year after hospital discharge, only 45 percent of patients were adherent to beta-blockers, with the biggest drop in adherence between 30 and 90 days. After accounting for multiple factors, significant predictors of lower adherence were participation in a Medicare+Choice (M+C) plan (compared with a commercial plan), residence in the Southeast, and younger age (35 to 64 years), driven by younger M+C participants (disabled or with end-stage renal disease) and by younger women within commercial plans.

The finding of lower adherence in M+C enrollees needs further study, suggest the researchers. Other cited research indicates that patients with M+C plans are more likely than patients in commercial plans to have caps on prescription coverage, tiered co-pays for generic versus patented medications, or generic-only coverage. Thus, the authors suggest that patients in M+C may have faced higher "out-of-pocket" costs than those in commercial plans. However, this study could not distinguish between patients who did not take their medications and those who purchased their drugs "out-of-pocket" without filing a prescription claim.

Although the study did not show an overall effect of sex, the subgroup of women aged 35-64 years with commercial insurance were less likely than men in their age group and less likely than older women to adhere to beta-blockers. Educational campaigns like the National Heart Lung and Blood Institute's "Heart Truth Campaign" and the American Heart Association's "Go Red for Women" are needed for younger women. To reap the potential benefits of beta-blockers to prevent problems after heart attack, programs must raise awareness among physicians, patients, and the public about the importance of maintaining beta-blocker therapy after heart attack. Interventions to improve beta-blocker adherence after heart attack must occur early (in the first month or 2 after discharge).

See "National evaluation of adherence to B-blocker therapy for 1 year after acute myocardial infarction in patients with commercial health insurance," by Judith M. Kramer, M.D., M.S., Bradley Hammill, M.A., Kevin J. Anstrom, Ph.D., and others, in the September 2006 American Heart Journal 152, pp. 454e1-454e8.

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