Validity and reliability of quality of recovery-35 Thai version: a prospective questionnaire-based study

BACKGROUND: The quality of patients’ recovery following surgery and anesthesia has been a matter of focus and concern over the past decade. The Quality of Recovery-40 (QoR-40) questionnaire was developed and validated for post-anesthesia patient evaluation. The QoR-40, however, is English-based and was tested and validated in Caucasian patients, a population that is culturally and behaviorally different from the Thai population. The objective of this study was to translate and modify the original English-language QoR-40 into the Thai language and evaluate the Quality of Recovery-35 Thai version for measuring health outcomes in Thai patients after surgery and anesthesia. METHODS: Translation was performed according to internationally recognized translation standards to ensure the integrity of the translated version. Consistent with the recommendations of 25 anesthesiologists, five questions from the original QoR-40 were excluded. The 35-item questionnaire was then translated into the Thai language and renamed the Quality of Recovery-35 Thai version (Thai QoR-35). Overall, 43 outpatients and 53 inpatients rated their health and recovery status using three patient evaluation tools: 100-mm Visual Analogue Scale–Recovery (VAS-R), six-item Activities of Daily Living (ADL) questionnaire, and Thai QoR-35. RESULTS: Overall, 90 % of patients took <10 min to complete the Thai QoR-35 questionnaire. The Thai QoR-35 and VAS-R showed good convergent validity (r = 0.84, P < 0.001). Discrimination validity was supported by a significant difference in mean scores for recovery among the Thai QoR-35, VAS-R, and ADL when compared between outpatients and inpatients (P < 0.01) and also between baseline and postoperative values (P < 0.001). The Thai QoR-35 also demonstrated good reliability with high internal consistency at three time points (Cronbach’s alpha = 0.88, 0.89, 0.91, respectively; P < 0.01) and a split-half reliability coefficient of 0.65 (P < 0.001). CONCLUSION: Thai QoR-35 is a valid, reliable tool for evaluating quality of recovery in Thai patients. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12871-016-0229-7) contains supplementary material, which is available to authorized users.