Background: Pain catastrophizing is 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. However, a Thai version of the UW-CAP6 has not yet been developed.

Objective: To 1) cross-culturally adapt the UW-CAP6 items into Thai, using the Functional Assessment of Chronic Illness Therapy translation methodology, and 2) evaluate its measurement properties.

Materials and Methods: Two hundred forty-one patients with chronic low back pain completed the Thai version of UW-CAP6 (T-UW-CAP6), the Thai Fear Avoidance Beliefs Questionnaire (T-FABQ), and the Thai Medical Outcome Study Short-Form 36 (T-SF-36). A subset of 152 participants completed the T-UW-CAP6 again after at least a 7-day interval.

Results: The T-UW-CAP6 had good internal consistency (Cronbach’s α=0.89) and moderate test-retest reliability [intraclass correlation coefficient (2, 1)=0.72]. The T-UW-CAP6 was positively correlated with the T-FABQ work and physical activity scales (Spearman’s rho=0.38 and 0.39, respectively), and negatively correlated with the social functioning, vitality, and mental health scales of the T-SF-36 (Spearman’s rho=–0.54, –0.41, and –0.45, respectively).

Conclusion: The T-UW-CAP6 demonstrated good psychometric properties for assessing pain catastrophizing in Thai individuals with chronic low back pain, supporting the use of the T-UW-CAP6 for clinical and research purposes in this population.

Keywords: Pain catastrophizing, Cross-cultural adaptation, Chronic low back pain, Reliability, Validity

DOI: doi.org/10.35755/jmedassocthai.2020.07.10931

Received 11 Feb 2020 | Revised 24 Apr 2020 | Accepted 27 Apr 2020