Abstract
Introduction: Diabetes is rapidly increasing in Iran, necessitating the improvement of treatment satisfaction to boost patients’ adherence and health outcomes. This research investigated the psychometric of the Persian version of the 9-item Treatment Satisfaction Questionnaire for Medication (TSQM-9) in patients diagnosed with type 2 diabetes mellitus (T2DM) in Iran.
Methods: This cross-sectional study, including 126 males and 274 females with T2DM recruited via convenience sampling, was conducted in Kerman, Iran, from January to February 2021. Internal consistency of the TSQM-9 was assessed using Cronbach’s alpha and item-total correlations, while construct validity was determined through structural equation modeling (SEM), known-groups comparison, and convergent validity assessment.
Results: Cronbach’s alpha for the TSQM-9 total scale and subscales (effectiveness, convenience, and global satisfaction) ranged from 0.91 to 0.98. Item-total correlation coefficients also ranged from 0.57 to 0.87, all exceeding the 0.30 threshold. Moreover, SEM fit indices indicated an adequate model fit (χ² = 71.5, DF = 25, P ≤ 0.001, CFI = 0.99, RMSEA = 0.06, TLI = 0.98, NFI = 0.98). The mean TSQM-9 scores for both hemoglobin A1C and fasting blood glucose significantly decreased across the first to third tertile groups, demonstrating good known group validity. For convergent validity, the Spearman correlation between the Morisky Medication Adherence Scale and the TSQM-9 total score was 0.33 (P < 0.001), indicating a weak but significant relationship.
Conclusion: Our findings revealed that the Persian TSQM-9 possesses adequate validity and reliability, making it suitable for assessing treatment satisfaction in Iranian patients with T2DM by clinicians and investigators.