Psychometric properties of the treatment satisfaction with medicine questionnaire (SATMED-Q) in Indonesian patients with type 2 diabetes

Abstract

OBJECTIVES: The Treatment Satisfaction with Medicine Questionnaire (SATMED-Q) is a valuable instrument for pharmacy practice research, but psychometric properties have not been investigated widely. Therefore, the aim of this study was to evaluate the psychometric properties of the Indonesian version of the SATMED-Q. METHODS: This was a cross-sectional study of patients with type 2 diabetes recruited from five community health centers in Indonesia. Participants completed the SATMED-Q, the Medication Adherence Report Scale (MARS-5), the 5 Level EuroQol 5 Dimensions (EQ-5D-5L) and the EuroQol Visual Analog Scale (EQ-VAS) instruments. Reliability and validity were tested. KEY FINDINGS: Overall, 486 patients (mean age 59 years old, 73.3% female) participated. Both internal reliability (Cronbach's alpha 0.97) and test-retest reliability (intraclass correlation coefficient ranging from 0.615 to 1 across the domains) were high. Exploratory factor analysis supported the original six domain structure, with factor loadings exceeding 0.5. Confirmatory factor analysis showed a well-fitted model (comparative fit index = 0.968, Tucker-Lewis index = 0.958, standardized root mean square residual = 0.051, chi2/df = 3.652) and a moderate root mean square error of approximation value of 0.074. Convergent validity was demonstrated by a significant positive correlation between SATMED-Q and MARS-5 (r = 0.276) and EQ-VAS (r = 0.330). CONCLUSIONS: The Indonesian SATMED-Q was found to be a valid and reliable instrument for assessing medication satisfaction as an important outcome to develop and evaluate pharmacy practice interventions.