Better medication adherence can improve outcomes and reduce costs of care for patients with coronary artery disease (CAD), according to a systematic literature review.

The study, a collaboration between CVS Caremark and Brigham and Women’s Hospital, in Boston, showed that improved adherence potentially could save up to $868 per patient annually. The results of the partnership appear in The American Journal of Medicine (2013;126:357.e7-357.e27, doi: 10.1016/j.amjmed.2012.09.004).

Lead investigator Asaf Bitton, MD, MPH, an instructor in medicine at Brigham and Women’s and Harvard Medical School, also in Boston, and his team conducted a systematic review of 45 years of literature on the association between better medication adherence and CAD outcomes and costs. After reviewing 2,636 articles published between 1966 and 2011, the team analyzed 25 studies in greater detail that met their inclusion criteria related to adherence and CAD outcomes.

The analysis showed a strong and consistent association between patients who had the highest medication adherence and improved CAD outcomes, including decreased mortality. Additionally, in the studies that measured costs, high adherence rates were associated with 17% lower costs per year. The studies used a variety of measures to define high versus low adherence. These measures included medication possession ratio (MPR), where an MPR greater than 80% was defined as high adherence and an MPR less than 80% was defined as low adherence; proportion of days covered (PDC), where a PDC greater than 80% was considered high adherence and a PDC less than 80% was considered low adherence; direct pill counts; and patient questionnaires.

“CAD and cardiovascular disease in general has an annual health care cost of about $475 billion. Our analysis showed that adherence not only improved health outcomes, it also … reduced total annual CAD costs consistently from $294 to $896 per patient,” Dr. Bitton told Pharmacy Practice News.

Pharmacy involvement plays a major role in getting patients to be more compliant with their medication, he added. “I practice in a patient-centered medical home here at Brigham and Women’s. We are one of the new team-based models of primary care and because we find that adherence is so important in determining the outcomes that our patients have, we have a full-time outpatient pharmacist in our clinic who works with patients on adherence, helps manage and do medication reconciliation, and guides those patients who have many different medications. We find it immensely helpful to have [such] pharmacist expertise and input on our team.”

Troyen A. Brennan, MD, MPH, the chief medical officer at CVS Caremark, noted that the company has been working with Brigham and Women’s Hospital to research pharmacy claims data in order to better understand patient behavior, particularly patient adherence. Dr. Brennan said the study is “significant because it broadens the discussion … about ways that we can best serve patients and meet their needs while reducing spending within the health care system.” The results, he added, “[offer] evidence that medication adherence strategies and interventions for CAD patients may be one way to [achieve those two goals].”