Establishing the interpretability and utility of the 4-item BriefPCS

To reduce the patient burden associated with completing the 13-item Pain Catastrophizing Scale (PCS), the 4-item "BriefPCS" was developed. To date, no crosswalk has been developed that associates scores on the BriefPCS with PCS scores. Further, no study has compared the use of BriefPCS and PCS scores in a randomized clinical trial (RCT). We aimed to: (1) establish the interpretability of BriefPCS scores in reference to PCS scores, (2) compare the concurrent validity between the BriefPCS and PCS, and (3) asssess the use of BriefPCS in an RCT. First, we conducted equipercentile linking, created a crosswalk that associated scores of BriefPCS with PCS, and calculated differences between PCS and crosswalked PCS scores. Secondly, we compared Bootstrap correlation coefficients between PCS and self-reported measures of other domains. Lastly, we compared results from an RCT using BriefPCS scores versus PCS scores. Findings indicated that the correlation coefficient estimates with the BriefPCS and PCS scores were not significantly different. BriefPCS and PCS scores had similar ability to detect treatment-related changes. The BriefPCS scores validly, reliably, and accurately distinguish levels of pain catastrophizing. Additionally, the BriefPCS scores are sensitive to changes after behavioral interventions, with less respondent burden compared to the PCS scores.