Validity and Reliability of the Thai Version of the 19-Item Compliance-Questionnaire-Rheumatology

To evaluate the psychometric properties and feasibility of the Thai version of Compliance-Questionnaire-Rheumatology (CQR)-19.

A cross-sectional study was conducted in the Rheumatology clinic of Siriraj hospital from October 2020 to March 2022. Literate patients diagnosed with rheumatoid arthritis and aged ≥ 18 years old were included. Participants completed the Thai CQR-19 at baseline and during a follow-up visit. A pill count at the follow-up visit indicating that ≤ 80% of prescribed pills were taken was defined as poor compliance. Feasibility was assessed by the time to completion and the number of missing questions.

156 participants were enrolled and 88% were in good compliance. The sensitivity of the CQR-19 to detect good compliance was 78.2% and the specificity was 27.8%. The Thai CQR-19 showed moderate agreement (Gwet's AC1= 0.61, p < 0.01) with 72.2% agreement against pill counts. The Thai CQR-19 had good internal consistency (Cronbach's alpha = 0.83) with moderate test-retest reliability (intraclass coefficients = 0.64, 95% CI 0.54-0.73; p < 0.05). There was a weak correlation between the Thai CQR-19 and disease activity (r = 0.20, p < 0.05), and no correlation with functional disability (r = 0.09, p = 0.25). The median (IQR) completion time was 4.42 (3.25-6.16) minutes and 114 (73%) completed all 19 questions.

The Thai version of CQR-19 is a valid and reliable tool to assess medication compliance in Thai patients with RA. To ensure completeness and accuracy, this questionnaire may be administered by interview.