Synthesizing and Appraising the Quality of the Evidence on Factors Associated with Medication Adherence in Diabetes: A Systematic Review of Systematic Reviews.

BACKGROUND: Nonadherence to medications is a common phenomenon in patients with diabetes. Several studies and systematic reviews have investigated the barriers to medication adherence in diabetes. However, no study has evaluated the quality of the existing literature and synthesized the plethora of evidence with a goal to design holistic conceptual frameworks and interventions.

OBJECTIVES: The aims of this review were to systematically evaluate existing systematic reviews focusing on factors associated with medication adherence in diabetes in an effort to synthesize the evidence, determine their methodological quality, and identify the gaps in the current literature.

METHODS: Fourteen databases and gray literature sources were systematically searched through June 2016. Systematic reviews reporting factors associated with medication adherence (barriers and facilitators) in patients with diabetes were selected on the basis of predetermined criteria. Studies were appraised for quality using AMSTAR (A Measurement Tool to Assess Systematic Reviews).

RESULTS: Seventeen systematic reviews including 542 primary studies, most of which were cross-sectional quantitative studies, were included. All the reviews were rated as moderate to low quality and exhibited common methodological pitfalls. Factors influencing medication adherence identified were categorized as patient-, medication-, disease-, health care provider-, health care system-, and social-related factors.

CONCLUSIONS: Factors influencing medication adherence are multifactorial with remarkably consistent findings across the existing reviews; yet, most reviews were judged to be of low to moderate quality. Further comprehensive and well-conducted original studies and systematic reviews on this topic shall be conducted taking into consideration the drawbacks of existing ones.