Factor structure and psychometric properties of the Chinese version of the 20-item Pain Anxiety Symptoms Scale (ChPASS-20).

Abstract

The Pain Anxiety Symptoms Scale (PASS) was designed to assess pain-related anxiety and fear. Although the scale is a reliable measure with good psychometric properties, its validity among ethnic Chinese has yet to be evaluated. This study aimed to translate the English-language version of the 20-item PASS into Chinese (ChPASS-20) and evaluate its factor structure, reliability, and validity. A total of 223 Chinese patients with chronic musculoskeletal pain attending orthopedic specialist clinics completed the ChPASS-20, the Chronic Pain Grade questionnaire, the Chinese version of the 11-item Tampa Scale of Kinesiophobia, the Hospital Anxiety and Depression Scale, and questions assessing sociodemographic and pain characteristics. Confirmatory factor analyses showed that all the five-factor solutions tested met the minimum acceptable fit criterion. The four ChPASS-20 subscales and the entire scale demonstrated good internal consistency (Cronbach's αs: 0.72-0.92). All ChPASS-20 scales showed significant positive correlations with depression, pain intensity, and disability. Hierarchical multiple regression analyses showed that the ChPASS-20 total score predicted concurrent depression [F(4,159)=11.97, P<0.001], pain intensity [F(4,161)=2.47, P<0.05], and pain disability [F(4,191)=5.47, P<0.001] scores, and the ChPASS-20 Avoidance subscale (standardized beta coefficient=0.21, P<0.05) emerged as a significant independent predictor of concurrent pain disability. Our data support the factorial validity, reliability, and construct validity of the ChPASS-20 in a Chinese population.