WOONSOCKET, R.I., Jan. 13, 2014 /PRNewswire/ -- New research conducted by CVS Caremark (NYSE: CVS) and Brigham and Women's Hospital published in the January 2014 issue of the American Heart Journal, validates the effectiveness of a widely-used standard for optimal medication adherence. The study confirmed that patients need to achieve a Medication Possession Ratio (MPR) of at least 80 percent – meaning they are adherent to 80 percent 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 (60-79 percent MPR) derived less clinical benefit from their prescribed medications and had higher levels of disease-related clinical events. An MPR of 80 percent has long been considered optimal, but this threshold had little empirical support. (Logo: http://photos.prnewswire.com/prnh/20100816/NE50800LOGO ) "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 A. Brennan, MD, MPH, Executive Vice President 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 (MI) 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).