Aim: To adapt the Brief Pain Inventory-Short Form (BPI-SF) to Polish and to evaluate its psychometric properties (validity and reliability) in patients with cancer pain and to use BPI-SF for pain assessment and monitoring of pain treatment.
Patients and methods: BPI-SF construct validity was established through factor analysis of the pain interference items (factor 1) and the pain intensity items (factor 2). The concurrent validity was established by the correlation of BPI-SF with the pain scale, role functioning, and global quality of life (QOL) of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ C 30) and with the performance status (Eastern Cooperative Oncology Group [ECOG] and Karnofsky Performance Scale [KPS]). BPI-SF reliability was assessed using the alpha-Cronbach coefficient. There were three (QLQ C 30, ECOG, KPS) or four measurements (BPI-SF) performed.
Results: BPI-SF factor analysis revealed two underlying constructs: pain severity and pain interference. The factor analysis resulted in high validity scores of both factors. Numerous significant correlations of BPI-SF with pain scale and role functioning, a few less significant corellations with global QL of the EORTC QLQ C 30 and modest correlations with ECOG and KPS. High alpha-Cronbach values were found for single items and for the whole pain intensity and pain interference factors (0.863-0.998).
Conclusions: The Polish version of BPI-SF is a valid and reliable tool recommended for pain assessment and monitoring of pain treatment in patients with cancer.