WOONSOCKET, R.I. — New research conducted by CVS Caremark and Brigham and Women's Hospital confirms that optimal adherence to medications prescribed after a heart attack reduces hospital readmissions.
The research was published in the January 2014 issue of the American Heart Journal.
The study confirmed that patients need to achieve a Medication Possession Ratio of at least 80%, meaning they are adherent to 80% or more of their prescription medications, in order to reduce their risk of hospital readmission after a heart attack. Patients with more moderate levels of medication adherence following a heart attack (60% to 79% MPR) derived less clinical benefit from their prescribed medications and had higher levels of disease-related clinical events. An MPR of 80% has long been considered optimal, but this threshold had little empirical support.
"These findings underscore the ongoing need for interventions to help patients improve their adherence while confirming the level of optimal adherence needed to see clinical benefit," said Troyen Brennan, EVP and chief medical officer of CVS Caremark, and a study co-author. "Interventions could range from identifying ways to remove financial barriers, to determining how best to simplify complicated treatment regimens, to providing tools to help remind and motivate patients about the importance of taking their medications as directed."
The researchers evaluated the impact of adherence on clinical outcomes for more than 4,100 myocardial infarction patients who had filled a prescription for at least one of the study medications (beta-blocker, statin, angiotensin converting enzyme inhibitor, or angiotensin receptor blocker) prescribed after hospital discharge. The study measured outcomes based on a patient's first hospital re-admission for a major vascular event (fatal or non-fatal acute MI, unstable angina, stroke, congestive heart failure) or coronary revascularization (coronary bypass, stenting or angioplasty).
The study found patients who achieved adherence equal to or greater than 80% MPR to each of the study medications were significantly less likely than the control group to experience a major vascular event or undergo revascularization. For example, patients with optimal adherence of 80% MPR or greater were 24% more likely not to be readmitted to the hospital for another heart-related issue than the control group. In contrast, partially adherent patients (60% to 79% MPR) had no significant reduction in clinical outcomes compared with the control group, despite achieving greater levels of medication adherence.
"While it is widely accepted that patients who are adherent to prescribed medications for chronic conditions have better outcomes than non-adherent patients, there has not been solid data that defines the optimal level of adherence," stated Niteesh Choudhry, associate physician, division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women's Hospital and associate professor, Harvard Medical School and the lead author of the study.
"This research clearly demonstrates that the long-held industry standard of 80% MPR is associated with improved health outcomes and reduced adverse coronary events for post-heart attack patients. The data also highlights that it is important for patients who have had a heart attack to reach optimal adherence for all of their recommended medications in order to derive maximal clinical benefit."
The study, entitled "Untangling the Relationship Between Medication Adherence and Post-Myocardial Infarction Outcomes," was based on a secondary analysis of data from the randomized MI FREEE (Free Rx Event and Economic Evaluation) trial conducted by Aetna and Brigham and Women's Hospital (full results of which were previously published in the New England Journal of Medicine in 2011).
CVS Caremark plans to use these research results along with other key information to identify, develop and pilot interventions that will help improve medication adherence for the patients. The company currently is evaluating and piloting a number of interventions that range from the development of models to predict a patient's adherence behaviors in order to better target interventions; to the use of medication reminder devices to help combat forgetfulness; to digital interventions that engage patients to encourage adherence.
CVS Caremark has been working in a multi-year collaboration with Brigham and Women's Hospital to research pharmacy claims data in order to better understand patient behavior, particularly around medication adherence. Annual excess healthcare costs because of medication nonadherence in the United States have been estimated to be as much as $290 billion.