Validation of a Simplified Chinese Version of the Pain Catastrophizing Scale and an Exploration of the Factors Predicting Catastrophizing in Pain Clinic Patients.

BACKGROUND Chronic pain is very common worldwide and can lead to disability, depression and absence from work. Catastrophizing has been proven to affect individuals' belief systems and coping strategies, and it is an essential risk factor for chronic pain. The pain catastrophizing scale (PCS) has been developed for the assessment of catastrophizing. However, a Chinese version of this scale is not available, and physicians are therefore unable to determine which patients are prone to catastrophizing. Additionally, the risk factors for catastrophizing are unknown. OBJECTIVE We aimed to cross-culturally adapt and validate the PCS for simplified Chinese (SC-PCS) and explore the risk factors for catastrophizing in patients from a pain clinic. STUDY DESIGN We utilized a prospective, nonrandomized, cross-sectional, descriptive survey design. A second analysis of test-retest reliability was performed in a longitudinal, observational study. SETTING A convenience sample was recruited from a pain clinic in a tertiary hospital. METHODS This study was performed in 3 stages. In the first stage, the PCS was translated and culturally adapted to create a Chinese version; in the second stage, the measurement properties of the SC-PCS were tested, including the content validity, construct validity and reliability; and in the third stage, factors affecting catastrophizing in a pain clinic setting were explored. The adaptation was performed using a forward-backward method, and content validity was analyzed by examining the response trend (Z-skewness and item-total correlation). Construct validity was analyzed by assessing structural validity (confirmatory factor analysis [CFA] and exploratory factor analysis [EFA]) and a priori hypothesis testing. Reliability was analyzed by internal consistency (Cronbach's alpha) and test-retest reliability (intraclass correlation coefficient [ICC]). Risk factors for catastrophizing were analyzed by multivariate linear regression. RESULTS A total of 153 patients were included, with a response rate of 96%; no items were excluded from the SC-PCS. Both CFA and EFA confirmed a 3-factor structure, and 9/10 of the hypotheses were verified for construct validity. Excellent reliability was acquired with a Cronbach's alpha of 0.91, and an ICC of 0.94 was determined. Risk factors for catastrophizing included college education (beta = 0.47), pain duration (beta = 0.40), female (beta = 0.31), freelancer status (beta = 0.31), and retired status (beta = 0.19). LIMITATIONS The recruited patients experienced severe pain or long-duration pain in a pain clinic setting. This may limit the applicability of the SC-PCS to patients with low or moderate pain levels. CONCLUSION The PCS has been linguistically translated into simplified Chinese and culturally adapted for a Chinese population with remarkable clinical acceptance, good construct validity, and excellent internal consistency and test-retest reliability. Education, pain duration, marital status, gender, income, and use of pain medications are important factors affecting catastrophizing.