Medication adherence rates, outcomes after MI may vary by hospital

Compared to hospitals in the lowest quartile of 90-day composite medication adherence, patients at hospitals with the highest adherence had lower two-year risk of major adverse cardiovascular events.


By 90 days postdischarge after acute myocardial infarction (MI), patient outcomes and adherence to secondary prevention medications appear to vary by hospital, a recent study found.

Researchers used data from nearly 20,000 Medicare patients discharged after MI from 347 U.S. hospitals participating in the Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With The Guidelines from Jan. 2, 2007, to Oct. 1, 2010. The study used Medicare Part D prescription filling data to determine patients' medication adherence, defined as the proportion of days covered more than 80% within 90 days after discharge, which was compared with two-year major adverse cardiovascular events. Results were published online on Jan. 31 by Circulation.

Overall rates of adherence were 68% for beta-blockers, 63% for statins, 64% for angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), and 72% for thienopyridines. Adherence rates varied significantly among hospitals: 59% to 75% for beta-blockers, 55% to 69% for statins, 57% to 69% for ACE inhibitors and ARBs, and 64% to 77% for thienopyridines.

Compared to hospitals in the lowest quartile of 90-day composite medication adherence, patients at hospitals with the highest adherence had lower two-year risk of major adverse cardiovascular events (27.5% vs. 35.3%; adjusted hazard ratio, 0.88; 95% CI, 0.80 to 0.96). Hospitals with the highest adherence also had lower adjusted rates of patients' dying or being readmitted compared to those with the lowest adherence (hazard ratio, 0.90; 95% CI, 0.85 to 0.96).

The study authors noted limitations of the analysis, including that they could not determine whether patients actually took the dispensed medications and a lack of data on individual hospital practices. They added that they did not capture adherence data for patients not enrolled in Medicare Part D or on alternate prescription coverage.

“Patient adherence is a critical component of an evolving healthcare system that is now prioritizing quality of care over traditional fee-for-service. We believe an understanding of factors associated with adherence on a hospital-level, in addition to those on a patient-level, provide a novel framework on which to further engage with the issues of poor medication adherence in healthcare,” the authors concluded.