Validity and reliability of the Thai version of the Spine Oncology Study Group Outcomes Questionnaire version 2.0 to assess Quality of Life in Patients with Spinal Metastasis

Abstract

Background Context: The Spine Oncology Study Group Outcomes Questionnaire version 2.0 (SOSGOQ2.0) is a spinal metastasis (SM)-specific quality of life (QoL) questionnaire that was previously reported to have good reliability and validity. There is currently no Thai version of the SOSGOQ 2.0. (TH-SOSGOQ2.0). Purpose: To assess the psychometric properties of the TH-SOSGOQ 2.0. Study Design/Setting: Cross-sectional study. Faculty of Medicine Siriraj Hospital, Mahidol University. Patient Sample: Patients who were confirmed diagnosis of metastatic spinal disease, age 18 to 75 years, and having already undergone surgery and/or radiotherapy for the treatment of spinal metastasis. Outcome Measures: Validity and reliability of the TH-SOSGOQ 2.0 to assess QoL in Patients with SM. Methods: Using the forward-backward translation technique, the SOSGOQ2.0 was translated into Thai language to create the TH-SOSGOQ2.0. SM patients were prospectively enrolled and evaluated for patient QoL using both the TH-SOSGOQ2.0 and the EQ-5D-5L (Thai version) at baseline and 3 months after treatment. Construct validity was assessed using multi-trait scaling analysis, confirmatory factor analysis, and correlation with EQ-5D-5L. Test-retest reliability was assessed in a subgroup of patients who took the TH-SOSGOQ2.0 two times one week apart. Results: Sixty-eight patients (mean age: 57 years; 30 males, 38 females) were included. The Cronbach's alpha values for the total score, physical function, neurological function, pain, mental health, social function, and post-therapy domains were 0.87, 0.89, 0.91, 0.84, 0.82, 0.75, and 0.85, respectively. Good reliability was demonstrated (interclass correlation coefficient range: 0.70-0.84), except for the social function domain (0.60). Regarding concurrent validity, the TH-SOSGOQ2.0 domains demonstrated moderate to good correlation with the corresponding EQ-5D-5L 9 (Thai version) domains (range: -0.32 to -0.78). Physical function was the most well-correlated domain with the EQ-5D-5L (Thai version) (-0.77). Conclusions: TH-SOSGOQ2.0 demonstrated good reliability and validity for assessing QoL in Thai SM patients.