Measurement structure of the pain self-efficacy questionnaire in a sample of Chinese patients with chronic pain

Objective: To examine the factorial structure of the Chinese translation of the Pain Self-Efficacy Questionnaire in a sample of Chinese patients with chronic pain. Setting: Outpatient physiotherapy department in a local hospital and a local rehabilitation clinic. Participants: One hundred and twenty patients with chronic pain in physiotherapy treatment. Methods: Each participant was asked to complete the Chinese version of the Pain Self-Efficacy Questionnaire, visual analogue scale (VAS), modified Roland Morris Disability Questionnaire, and Short Form Health Survey (SF-36). The test structure of the Pain Self-Efficacy Questionnaire was evaluated by confirmatory factor analysis. Highly correlated paths were added onto the initial structure for improving the final construct for the Pain Self-Efficacy Questionnaire. The correlations between the Chinese Pain Self-Efficacy Questionnaire and related measurements were computed using Pearson product-moment correlation coefficients. Results: Confirmatory factor analysis indicated that the one-factor model provided the best fit between the model and data, with the chi-square of the respecified model computed to be 36.79 (33, N = 120), the goodness-of-fit index 0.940, cumulative fit index 0.996, and the root mean square error of approximation 0.031. The item-total correlations ranged from 0.70 to 0.85. Cronbach's alpha of the Chinese version of the Pain Self-Efficacy Questionnaire was computed to be 0.94. The total scores also correlated significantly with the modified Roland Morris Disability Questionnaire and six subscales of SF-36. Conclusion: A single-factor model confirmed the unidimensionality of the Chinese version of the Pain Self-Efficacy Questionnaire in a sample of Chinese patients with chronic pain. It demonstrated good internal consistency reliability and construct-related validity.