Analysis of Pain and Interference Patterns With Brief Pain Inventory in Patients With Bone Metastases: A Confirmatory Study

Background This study investigates the validity of the psychometric properties of the Brief Pain Inventory (BPI) in patients with bone metastases and determines if patients with lower body pain exhibit higher levels of activity interference than those with upper body pain. Methods Three hundred and eighty-six patients treated, between May 2003 and June 2007, for painful bone metastases were included in this analysis, 336 patients with complete data were included in further analyses. Cronbach's Alpha, confirmatory factor analysis (CFA), and discriminant validity tests were performed to analyze the psychometric properties of the BPI. One-way analysis of variance was used to compare mean scores of BPI subscales (pain, activity, and affect) in patients with upper or lower bone metastases. Results Internal consistency of two- and three-factor BPI analysis was high. In both cases, consistency was further improved when the sleep item was removed. CFA confirmed these results and showed that three-factor analysis was recommended. Patients with lower body metastases reporting moderate to severe pain exhibited greater levels of functional interference. A single fraction radiotherapy dose of 8 Gy was as effective as multi-fraction therapy where the predominant fractionation was 20 Gy in 5 fractions. Conclusions Our data confirms the psychometric validation of the BPI and the recommendations to use three-factor analysis in patients with bone metastases. Patients exhibiting lower extremity pain should receive prompt pain interventions and functional aid.