After two years of hospital discharge, 41.6 percent of Medicare beneficiaries who were hospitalized for MI were taking high-intensity statins with high adherence, 19.1 percent had low adherence and 18.1 percent stopped taking statins, according to a retrospective study.

The adults were between 66 and 75 years old. The researchers noted that the proportion of adults taking high-intensity statins with high adherence increased between 2007 and 2012. They found similar results for adults who were older than 75 years old.

Lead researcher Lisandro D. Colantonio, MD, MSc, of the University of Alabama at Birmingham, and colleagues published their results online in JAMA Cardiology on April 19. Amgen funded the study through a research grant.

"A substantial proportion of patients filling high-intensity statin prescriptions following [an MI] do not continue taking this medication with high adherence and may benefit from interventions aimed to improve high-intensity statin use,” the researchers wrote.

In 2013, the American College of Cardiology and American Heart Association released guidelines that recommended high-intensity statins for patients with cardiovascular disease who are 75 years old or younger. The guidelines also recommend moderate-intensity statins for patients with cardiovascular disease who are older than 75, although high-intensity statins could be appropriate for some patients.

For this analysis, the researchers evaluated 57,898 Medicare beneficiaries who were 66 or older and were hospitalized with an MI between 2007 and 2012. All of the patients filled a high-intensity statin prescription within 30 days of hospital discharge. They also had continuous fee-for-service coverage from one year through six months after their MI hospitalization.

The researchers defined high adherence as a proportion of days covered of at least 80 percent for high-intensity statins without low/moderate-intensity statin prescription fills. They considered low adherence as a proportion of days covered of less than 80 percent.

At six months post-discharge, 58.9 percent of beneficiaries from 66 to 75 years old continued taking a high-intensity statin with high adherence, 8.7 percent down-titrated to a low/moderate-intensity statin with high adherence, 17.3 percent had low statin adherence and 12.4 percent discontinued their statin use.

In addition, 64 percent of adults who took high-intensity statins with high adherence at six months continued to have high adherence at two years. Meanwhile, only a few adults who had low adherence or discontinued statin therapy at six months took high- or low/moderate-intensity statins with high adherence at one year, 18 months and two years.

After adjusting for multiple variables, the researchers found that beneficiaries with dual Medicare/Medicaid coverage, cardiac rehabilitation, more cardiologist visits and a medication coverage gap after discharge were more likely to continue taking high-intensity statins with high adherence at six months and two years after discharge. They added that African-American patients, Hispanic patients and new high-intensity statin users were less likely to continue taking a high-intensity statin with high adherence.

The researchers acknowledged a few limitations of the study, including that using pharmacy claims could lead to misclassification of statin use patterns. They also did not consider characteristics of the hospital where the patient was treated for their MI and did not have information on the reasons for statin down-titration or discontinuation.

“Results from this study indicate that many patients who fill a high-intensity statin following an MI hospitalization do not continue taking this medication with high adherence during the two years [after] discharge,” the researchers wrote. “Lower medication costs, cardiologist visits and cardiac rehabilitation may contribute to improving high-intensity statin use and adherence after myocardial infarction.”