Evaluation of Psychometric Properties of the Simplified Medication Adherence Questionnaire (SMAQ) in Albanian Older Adults with Complex Chronic Conditions

Background: Medication adherence is essential for effective management of chronic conditions, particularly among older adults with complex chronic conditions (CCCs). The Simplified Medication Adherence Questionnaire (SMAQ) is a brief self-report instrument widely used to assess adherence; however, its psychometric properties have not been evaluated in Albanian older populations. Objective: To assess the psychometric properties of the SMAQ in Albanian older adults with CCCs. Methods: A multicenter, cross-sectional study was conducted among 727 adults aged ≥65 years with two or more chronic conditions recruited from primary healthcare centers in southern Albania. Internal consistency was assessed using Cronbach’s alpha and McDonald’s ω. Construct validity was evaluated through exploratory and confirmatory factor analyses and correlations with clinical and behavioral variables. Discriminative validity was examined using known-group approach and independent samples t-tests, and criterion validity was assessed using Spearman correlations. Results: The SMAQ demonstrated good internal consistency (α = 0.799, ω = 0.821). Factor analyses supported a unidimensional structure, with all items loading significantly onto a single factor. Model fit indices indicated acceptable fit (CFI = 0.921; SRMR = 0.051), although RMSEA suggested some misfit (0.116). Non-adherent participants had significantly higher SMAQ scores than adherent participants (p < 0.001), indicating strong discriminative validity. Conclusions: The SMAQ is a reliable and valid tool for assessing medication adherence among Albanian older adults with CCCs, supporting its use in primary healthcare and research settings.