Psychometric properties of the Japanese version of short forms of the Pain Catastrophizing Scale in participants with musculoskeletal pain: A cross-sectional study

Background: The Pain Catastrophizing Scale (PCS) is a commonly used as measure of pain catastrophizing. The scale comprises 13 items related to magnification, rumination, and helplessness. To facilitate quick screening and to reduce participant's burden, the four-item and six-item short forms of the English version of the PCS were developed. The purpose of the present study was to evaluate the psychometric properties of a Japanese version of the short forms of PCS using a contemporary approach called Rasch analysis. Methods: A total of 216 patients with musculoskeletal disorders were recruited in this study. Participants completed study measures, which included the pain intensity, the Pain Catastrophizing Scale (PCS), and the Tampa Scale of Kinesiophobia (TSK). Furthermore, the four-item (items 3, 6, 8, and 11) and six-item (items 4, 5, 6, 10, 11, and 13) short forms of the Japanese version of PCS were measured. We used Rasch analysis to analyze the psychometric properties of the original, four-item, and six-item short forms of PCS. Results: Rasch analysis showed that both short forms of PCS had acceptable internal consistency, unidimensionality, and no notable DIF and were functional on the category rating scale. However, fouritem short form of PCS had two misfit items. Conclusions: Six-item short form of PCS has acceptable psychometric properties and is suitable for use in participants with musculoskeletal pain. Thus, six-item can be used as brief instruments to evaluate pain catastrophizing. (C) 2016 The Japanese Orthopaedic Association. Published by Elsevier B. V. All rights reserved.