Medication Adherence With Diabetes Medication: A Systematic Review of the Literature

Purpose The primary purpose of this systematic review is to synthesize the evidence regarding risk factors associated with nonadherence to prescribed glucose-lowering agents, the impact of nonadherence on glycemic control and the economics of diabetes care, and the interventions designed to improve adherence. Methods Medline, EMBASE, the Cochrane Collaborative, BIOSIS, and the Health and Psychosocial Instruments databases were searched for studies of medication adherence for the period from May 2007 to December 2014. Inclusion criteria were study design and primary outcome measuring or characterizing adherence. Published evidence was graded according to the American Association of Clinical Endocrinologists protocol for standardized production of clinical practice guidelines. Results One hundred ninety-six published articles were reviewed; 98 met inclusion criteria. Factors including age, race, health beliefs, medication cost, co-pays, Medicare Part D coverage gap, insulin use, health literacy, primary nonadherence, and early nonpersistence significantly affect adherence. Higher adherence was associated with improved glycemic control, fewer emergency department visits, decreased hospitalizations, and lower medical costs. Adherence was lower when medications were not tolerated or were taken more than twice daily, with concomitant depression, and with skepticism about the importance of medication. Intervention trials show the use of phone interventions, integrative health coaching, case managers, pharmacists, education, and point-of-care testing improve adherence. Conclusion Medication adherence remains an important consideration in diabetes care. Health professionals working with individuals with diabetes (eg, diabetes educators) are in a key position to assess risks for nonadherence, to develop strategies to facilitate medication taking, and to provide ongoing support and assessment of adherence at each visit.