Improving Medication Adherence: Keep Your Eyes on the Prize

M edication adherence is a set of complex health behaviors that challenges patients of all ages and health conditions. Researchers have spent decades trying to improve medication adherence, and yet these interventions have been wrought with limitations and sobering findings. The most recent Cochrane systematic review of the impact of adherence interventions found that effects were inconsistent across studies and that only a small number of interventions led to a modest improvement in both adherence and clinical outcomes. The authors concluded that existing adherence interventions Bare mostly complex and not very effective.^ In addition, the authors recommended that future research include robust study designs of feasible long-term interventions with sufficient study power to detect improvements in patientcentered clinical outcomes. A key issue in implementing any adherence intervention is ensuring valid measurement of adherence. Measurement of medication adherence is complex, since most measures serve as proxies for medication-taking behavior. For example, pharmacy claims data are increasingly used for conducting adherence research, although the pharmacy claim serves only as a proxy for medication consumption, and in reality it is simply measuring refills. Other methods for measurement, including self-report, pill counts, and electronic capture of pill bottle opening, also require important assumptions about the relationship between the measure and actual medication-taking. It is further assumed that improving medication adherence will improve process measures such as blood pressure or cholesterol control, which will in turn improve the health outcome(s) of patients including quality of life and mortality. In this issue of JGIM, Reddy and colleagues present findings on the effect of daily pill bottle alarms combined with individual or partner feedback reports on statin medication adherence. This 3-month, three-arm randomized clinical trial randomized 126 veterans with known coronary artery disease and poor adherence (medication possession ratio [MPR] <80 %) to one of three groups: (1) a control group that received a pill-monitoring device (i.e., a GlowCap bottle) with no alarms or feedback; (2) an individual feedback group that received a daily alarm and a weekly medication adherence feedback report; and (3) a partner feedback group that received an alarm and a weekly feedback report that was shared with a friend, family member, or a peer. By the end of the 3-month intervention, statin adherence was significantly higher in both the individual and partner feedback groups compared to the control arm (89 % and 86% vs. 67%, respectively). However, at 6 months, statin adherence did not differ among the groups (60 % and 52 % vs. 54 %). The study had a number of strengths and unique aspects. First, the use of a feedback component in the intervention arms was a novel approach. The authors were thus able to assess the impact of peer support (via social forces) or individual feedback on medication adherence behavior above and beyond the reminder effects of the GlowCap bottle. The use of peer support is increasing in behavior change interventions, and the application to adherence interventions is important and should be further investigated. Second, the study included only patients who had suboptimal medication adherence at baseline as measured by a 16-month statin MPR <80 %. In other words, the study targeted patients who had a documented need for intervention on some level. Interventions targeting individuals with medication adherence problems can have modest but significant effects on medication-taking behavior. Additional research is needed to further test this and other riskstratification approaches for improving medication adherence and the targeting of interventions. Despite these strengths, some limitations deserve mention, most notably concerns about adherence measurement. The medication adherence measure was the GlowCap bottle, which includes a computer chip in the lid that detects and time-stamps when the lid is removed. This is similar to the Medication Event Monitoring System (MEMS), which is considered a Bgold standard^ measure of medication adherence in trial settings. However, it is important to remember that it is an indirect method of measurement—opening the bottle does not equal taking the statin. It is entirely plausible, as the authors discuss, that patients receiving feedback reports were more likely to open the bottle but no more likely to take the medication. These concerns are magnified given the lack of change in LDL seen in the intervention groups. Despite the positive impact of the intervention on opening the pill bottle, it was found to have no significant effect on LDL levels at 6 months. In fact, the control group had numerically greater absolute Published online November 15, 2016