Among adults with chronic illness, 30% to 50% of medications are not taken as prescribed. In the United States, it is estimated that medication nonadherence is associated with 125 000 deaths, 10% of hospitalizations, and $100 billion in health care services annually.
PubMed was searched from January 1, 2000, to September 6, 2018, for English-language randomized clinical trials of interventions to improve medication adherence. Trials of patients younger than 18 years, trials that used self-report as the primary adherence outcome, and trials with follow-up periods less than 6 months were excluded; 49 trials were included. The most common methods of identifying patients at risk for nonadherence were patient self-report, electronic drug monitors (pill bottles), or pharmacy claims data to measure gaps in supply. Patient self-report is the most practical method of identifying nonadherent patients in the context of clinical care but may overestimate adherence compared with objective methods such as electronic drug monitors and pharmacy claims data. Six categories of interventions, and characteristics of successful interventions within each category, were identified: patient education (eg, recurrent and personalized telephone counseling sessions with health educators); medication regimen management (using combination pills to reduce the number of pills patients take daily); clinical pharmacist consultation for chronic disease co-management (including education, increased frequency of disease monitoring via telephone or in-person follow-up visits, and refill reminders); cognitive behavioral therapies (such as motivational interviewing by trained counselors); medication-taking reminders (such as refill reminder calls or use of electronic drug monitors for real-time monitoring and reminding); and incentives to promote adherence (such as reducing co-payments and paying patients and clinicians for achieving disease management goals). The choice of intervention to promote adherence will depend on feasibility and availability within a practice or health system. Successful interventions that are also clinically practical include using combination pills to reduce daily pill burden, clinical pharmacist consultation for disease co-management, and medication-taking reminders such as telephone calls to prompt refills (maximum observed absolute improvements in adherence of 10%, 15%, and 33%, respectively).
Conclusions and Relevance
Adherence can be assessed and improved within the context of usual clinical care, but more intensive and costly interventions that have demonstrated success will require additional investments by health systems.