Patient Preference and Adherence (May 2018)
Translation, revision, and validation of the Chinese version of the Satisfaction with Oral Anti-Diabetic Agent Scale (C-SOADAS) in patients with type 2 diabetes mellitus
Abstract
Yi-Ju Lin,1 Chin-Yuan Wang,2 Elizabeth H Chang,1,3,4 Ssu-Wei Cheng,5 Yu Ko1,4 1Department of Clinical Pharmacy, School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan; 2Department of Internal Medicine, Division of Endocrinology and Metabolism, National Taiwan University Hospital, Taipei, Taiwan; 3Department of Pharmacy, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; 4Research Center for Pharmacoeconomics, College of Pharmacy, Taipei Medical University, Taipei, Taiwan; 5Department of Pharmacy, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan Objective: The aim of this study was to translate, adapt, and validate the Satisfaction with Oral Anti-Diabetic Agent Scale (SOADAS) in type 2 diabetes mellitus (DM) patients taking oral antidiabetic drugs (OADs) in Taiwan. Patients and methods: The SOADAS was translated to Chinese and was modified based on reviews of two physicians, five diabetes educators, and two patient focus groups. A cross-sectional interviewer-administered survey was conducted in adult patients with type 2 DM who were taking OADs. The Chinese version of the SOADAS (C-SOADAS), the EuroQol 5 dimensions 3-level (EQ-5D-3L) questionnaire, and a demographic questionnaire were administered to participants. Instrument structure, internal consistency, convergent validity, and known-group validity were assessed. Results: A total of 260 DM patients were recruited. The mean score of an individual item ranged from 3.6 to 3.9, while the mean total score (out of 25 possible points) was 18.7 points. Overall, floor and ceiling effects were negligible. The Cronbach’s α value was 0.81. All the four predetermined hypotheses for known-group validity assessment were fulfilled. In convergent validity testing, the C-SOADAS total scores were found to be correlated with EuroQol-Visual Analog Scale (EQ-VAS) scores (r = 0.2; p < 0.01) but not with EuroQol 5 dimensions (EQ-5D) index scores (r = 0.02; p = 0.81). Conclusion: The 5-item C-SOADAS appears to be a psychometrically acceptable measure of OAD treatment satisfaction among type 2 DM patients in Taiwan. The tool may be incorporated into clinical practice to quickly assess treatment outcomes from patients’ perspectives. Keywords: diabetes mellitus, oral antidiabetic agent, satisfaction, validation, reliability, C-SOADAS, Taiwan
