Cross-cultural adaptation and psychometric properties of the Thai version of the University of Washington - Concerns About Pain Scale 6 (UW-CAP6)

Abstract

Background: Pain catastrophizing has been shown to be an important psychosocial factor that predicts disability and other important pain-related outcomes in individuals with chronic pain. The University of Washington - Concerns about Pain scale (UW-CAP6) is the brief version of a new item bank that assesses pain-related catastrophizing. Objective: To cross-culturally adapt the UW-CAP6 items into Thai and to evaluate its psychometric properties. Methods: The original UW-CAP6 instructions and items were cross-culturally adapted into Thai using the Functional Assessment of Chronic Illness Therapy translation methodology. Chronic low back pain individuals completed the Thai version of UW-CAP6 (T-UW-CAP6), Thai Fear Avoidance Beliefs Questionnaire (T-FABQ), and Thai Medical Outcome Study Short-Form 36 (T-SF-36). A subset of 152 participants completed the T-UW-CAP6 again after a 7-day interval. Psychometric testing included evaluation of its internal consistency (Cronbach’s alpha-α), test-retest reliability (intra-class coefficient correlations - ICC), and construct validity (Spearman correlation coefficients between the T-UW-CAP6 score and the measures of the validity criterion variables). Results: The T-UW-CAP6 showed good internal consistency (Cronbach’s α = 0.89) and moderate test-retest reliability (ICC [2,1] = 0.72). The T-UW-CAP6 was positively correlated with the T-FABQ Work and Physical Activity scales (r = 0.38 and 0.39, respectively) and negatively correlated with the Social Functioning, Vitality, and Mental Health scales of the T-SF-36 (r = -0.54, -0.41, and -0.45, respectively). Conclusion: The T-UW-CAP6 demonstrated good psychometric properties for assessing pain catastrophizing in a sample of individuals with chronic low back pain. The findings support the use of the T-UW-CAP6 for clinical and research purposes.