Self-efficacy for medication management: a systematic review of instruments

Background: Medication self-efficacy is a potentially important construct in research around optimal use of prescription medications. A number of medication self-efficacy measures are available; however, there is no systematic review of existing instruments and cataloguing of their theoretical underpinnings or psychometric properties, strengths, and weaknesses. The aim of the study was to identify instruments that measure self-efficacy for medication management. The study also aimed to examine the quality, theoretical grounding, and psychometric evaluation of existing measures of self-efficacy for medication management. The study was a systematic review. Methods: Data were extracted from PubMed, OVID, and MEDLINE using a predefined search strategy. Citations were included if they reported the development and/or psychometric evaluation of an instrument to measure self-efficacy for medication management and were in English. Abstracts were screened for studies potentially meeting eligibility criteria. Full articles of these studies were then reviewed in depth. The review was carried out independently by two members of the research team. Results: The search identified 158 citations of which 12 were included after screening. Full review identified 3 articles fitting inclusion criteria for the review. Generally, development was theoretically grounded and included patients and experts in the field. Psychometric testing showed evidence of internal consistency (2/3 instruments) and test-retest reliability (1/3 instruments). All instruments showed some validity; however, assessment of all forms of validity for each instrument was lacking. Conclusion: Although our analysis would recommend the use of the Self-Efficacy for Appropriate Medication Use Scale because of the current evidence of validity and reliability, more psychometric evaluation is required, particularly in terms of responsiveness to change as self-efficacy is a malleable patient-level factor. Three measures of self-efficacy for medication management were identified. Overall, some evidence of reliability and/or validity was demonstrated for all instruments; however, other forms of validity were not tested (ie, responsiveness to change). Use of a well-validated measure of self-efficacy medication management is essential in order to understand relationships between medication self-efficacy and other patient-reported outcomes such as patient-centeredness, patient enablement, and burden of treatment, an important area of research that is currently lacking.