Measuring the interference of pain on daily life in persons with spinal cord injury: A Rasch-validated subset of items from the Brief Pain Inventory interference scale.

Background/aim: Up to 60% of individuals report chronic pain after traumatic spinal cord injury (SCI). Measurement of the degree to which pain interferes with activities and emotions can provide valuable clinical insights with implications for pain management interventions. One questionnaire that can be used to quantify the impact of pain is the Brief Pain Inventory (BPI) interference scale, a seven-item self-report assessment. Our objective was to examine the Rasch measurement properties of the BPI interference scale for measuring pain interference in persons with SCI.

Methods: A secondary analysis of cross-sectional, population-based, self-report data was conducted. Participants were adults with traumatic SCI with residual effects who were at least one year post-injury and 18 years of age (n = 876). Rasch analysis was used to evaluate the measurement properties of the BPI interference items for persons with SCI.

Results: Two BPI interference scale items were excluded from analysis due to high rates of missing data. Of the remaining five items, four items demonstrated acceptable measurement properties in the SCI population.

Conclusion: Four of the original seven BPI interference items provide acceptable measurements of pain interference in the SCI population.