New York—Higher rates of adherence to cardiovascular maintenance medications are significantly associated with improved patient outcomes, as well as reductions in healthcare costs, according to new research.

Results of the so-called Minerva study, “Assessing the Impact of Medication Adherence on Long-term Cardiovascular Outcomes,” were published recently in The Journal of the American College of Cardiology (JACC). It investigated the link between medication adherence and long-term major adverse cardiovascular events (MACE) in patients’ postmyocardial infarction (MI) and those with atherosclerotic disease (ATH).

Background information in the article notes that nearly half of the 83 million Americans with established atherosclerotic disease do not follow prescribed drug regimens 2 years after an initial cardiovascular event.

“One of the biggest challenges cardiologists face with patients who have already experienced a cardiovascular event is medication adherence,” said principal investigator Valentin Fuster, MD, PhD, director of the Zena and Michael A. Wiener Cardiovascular Institute at the Icahn School of Medicine at Mount Sinai in New York and General Director of Spain's National Center for Cardiovascular Research (CNIC). “Often, patients diligently follow medication regimens immediately following a CV event, like a heart attack, only to falter as time progresses—either because prescriptions become too expensive or because they become discouraged by the pill burden associated with the post-CV event regimen.”

For the study, investigators queried the claims database of a large health insurer for patients hospitalized for MI or with ATH, with the primary outcome measure a composite of all-cause death, MI, stroke, or coronary revascularization. Patients were grouped as fully adherent (greater or equal to 80%), partially adherent (greater or equal to 40% to less than or equal to 79%), or nonadherent (less than 40%) using proportion of days covered for statins and angiotensin-converting enzyme inhibitors. Annual direct medical (ADM) costs were estimated per patient by using unit costs from two national files.

Past research has emphasized that acute post-MI patients must maintain a very high level of adherence to prevent a secondary cardiovascular event. Yet, these study results indicate that, in the post-MI cohort including 4,015 adults who initiated both statins and ACEI medications, only 43% percent of patients were classified as fully adherent, 31% were classified as partially adherent, and 26% patients were classified as nonadherent.

Study authors report that fully adherent patients were at a significantly lower risk of MACE than partially adherent—a 19% reduction—and nonadherent populations—a 27% risk reduction. In fact, no statistical difference in risk was observed between the nonadherent and partially adherent groups.

Furthermore, results indicate that full adherence was associated with reduced per patient annual direct medical costs associated with hospitalizations for MI of $369 and $440 and for revascularizations of $539 and $844 over partial and nonadherence, respectively.

The ATH cohort—which included 12,976 adults who initiated both statin and ace-inhibitor (ACEI) medications and also had two coronary, cerebrovascular, or peripheral artery disease ICD codes within one category or a revascularization code—was even less likely to take all prescribed medications, with only 34% fully adherent.

Results indicate that fully adherent patients in that group had significantly lower risk of MACE compared to the two other categories—a 44% risk reduction compared to nonadherent patients and 24% risk reduction compared to partially adherent patients. Also shown was a statistically significant reduction in hospitalizations of the composite outcome compared to the nonadherent group, and full adherence was associated with reduced per patient annual direct medical costs associated with hospitalization for MI of $116 and $215 and for revascularizations of $288 and $799 over partial and nonadherence respectively.

Lead author Sameer Bansilal, MD, MS, pointed out in an American College of Cardiology press release, “We have spent the last two decades generating evidence for the efficacy and safety for these drugs—now it’s time to make sure we deliver them adequately!”

Fuster, meanwhile, promoted more counseling and the possible use of a cardiovascular polypill to improve adherence.

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