Further validation of a portuguese version of the brief pain inventory interference scale

Chronic pain is a significant health problem which interferes with patients daily functioning and quality of life. Valid and reliable measures of pain-related interference are needed to provide adequate care to patients and monitor changes in pain and functioning over time. This study sought to evaluate the reliability and validity of a Portuguese version of the Brief Pain Inventory (P-BPI) interference scale. Two hundred and fourteen patients with chronic musculoskeletal pain completed the P-BPI, 0-10 NRS of pain intensity, Short Form-12 Health Status Questionnaire (SF-12), Hospital Anxiety and Depression Scale (HADS). The P-BPI demonstrated excellent internal consistency (Cronbach´s alpha = .91) and showed moderate associations with the criterion measures (all rs .30 or larger), supporting its construct validity. Confirmatory factor analysis of the P-BPI items yielded a single factor, further supporting its construct validity. The results provide strong support for the reliability and validity of the P-BPI interference scale.