Factor Structure of the Brief Pain Inventory-Short Form in African American Older Adults With Osteoarthritis.

Abstract

Purpose: To evaluate the factor structure of the Brief Pain Inventory-Short Form (BPI-SF) and measurement invariance across two age groups for African American (AA) older adults with osteoarthritis (OA).

Method: Participants were AA older adults aged 50 to 94 years with self-reported OA and chronic pain (N = 110). Cross-sectional data from the BPI-SF were obtained from all participants, and confirmatory factor analysis (CFA) was used to evaluate the factor structure. Measurement invariance across young-old (aged 50 to 69 years) and old-old (aged 70 to 94 years) participants was examined at configural, full metric, and full scalar levels.

Results: CFA revealed that a three-factor model (i.e., pain intensity, activity interference, and affective interference) demonstrated the best fit (χ²/df = 1.595, comparative fit index [CFI] = 0.949, root-mean-square error of approximation = 0.074). The change of CFI between configural and metric invariance was below the cutoff point of 0.01, supporting full metric (i.e., factor loadings) invariance across the two age groups. However, full scalar (i.e., item intercepts) invariance was not demonstrated.

Conclusion: Results support a three-factor structure of the BPI-SF, which is consistent across two age groups for AA older adults with OA. This study provides evidence that the BPI-SF can reliably measure pain intensity and two distinct dimensions of pain interference in this population. [Journal of Gerontological Nursing, 51(2), 13-22.].