Use of a Self-Report Medication Adherence Scale for Measuring Adherence to Antiretroviral Therapy in Patients With HIV/AIDS

BACKGROUND AND PURPOSE: This study examined the psychometric properties of a 9-item Morisky Medication Adherence Scale (MMAS-9) adapted specifically for patients with HIV/AIDS. METHODS: We used data from two randomized controlled trials investigating telephone-delivered interventions for improving adherence to antiretroviral therapy to assess reliability (Cronbach's α and Pearson's product correlation) and validity (convergent and concurrent) of the MMAS-9. RESULTS: The internal consistency (Cronbach's α) of the MMAS-9 was .66 (study 1) and .69 (study 2); 3-month test-retest reliability (Pearson's correlation) ranged from .50 to .74. Validity was supported by associations with electronic event monitored adherence, social support, depressive symptoms, self-efficacy, stigma, regimen complexity, and impact of side effects in the hypothesized direction. CONCLUSIONS: The adapted MMAS-9 demonstrated good convergent validity but somewhat lower internal consistency reliability than other reports.