Evaluating the psychometric properties of two-item and four-item short forms of the Japanese Pain Self-Efficacy Questionnaire: a cross-sectional study

PurposeThe Pain Self-Efficacy Questionnaire is a valid measure assessing self-efficacy in individuals with chronic pain. Short-form versions of the measure have been developed to decrease the assessment burden. However, few studies have evaluated the psychometric properties of the short forms in languages other than English. The aim of this study was to evaluate two 2-item short forms and one 4-item short form of the Japanese Pain Self-Efficacy Questionnaire in terms of internal consistency, criterion validity, structural validity, and construct validity.MethodsThis was a cross-sectional study. Data from 150 individuals with mixed chronic pain at a pain management center in a university hospital were extracted from clinical records and analyzed. The data included the information of the original version and short forms of the Japanese Pain Self-Efficacy Questionnaire, and other pain-related measures assessing pain intensity, pain interference, anxiety, depression and pain catastrophizing.ResultsItem statistics supported the item selection for each of the three short forms. All the short forms demonstrated adequate internal consistency and criterion validity. With respect to construct validity, one of the 2-item short forms failed to meet the criterion regarding the change in the magnitude of correlation with a depression scale. The 4-item short form met all the criteria including structural validity.ConclusionThe study findings provide evidence for the reliability and validity of 2- and 4-item versions of the Japanese Pain Self-Efficacy Questionnaire for use in clinical and research settings.