4.1.3 Brief Pain Inventory
The Brief Pain Inventory (BPI) was developed in 1983 to assess pain in individuals with cancer115. Unlike the unidimensional VAS and NRS tools, not only does it capture pain severity (derived from the average of four NRS pain intensity questions)116, but also calculates an accompanying pain interference score, derived from seven items which evaluate how pain affects ability to participate in activities of daily living. Together, these scores produce an overall rating between zero and 70, reflecting the intensity, chronicity, and functional impact of pain115.
With a completion time of approximately five minutes, and multidimensional approach to pain assessment117, the BPI is particularly valuable when assessing individuals with co-occurring OUD and chronic pain114. Notably, it has been endorsed by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) for use in chronic pain trials due to its “reliable, validated assessment of pain’s impact on physical functioning”118.
With respect to its applicability to persons with co-occurring OUD and chronic pain, the BPI was used by Hall and colleagues to assess the relationship between pain interference and central sensitization (an abnormal state of responsiveness of the nociceptive system)119 in 141 patients with OUD120. Nearly 90% of participants reported chronic widespread pain, often meeting diagnostic criteria for fibromyalgia, and those with higher levels of central sensitization (assessed by the American College of Rheumatology Fibromyalgia Survey), were more likely to report BPI pain interference as a reason for delaying OUD treatment, continuing and escalating opioid use, and returning to non-medical opioid use. In short, the BPI assesses multiple dimensions of pain, providing a more comprehensive characterization than unidimensional intensity scales like the VAS or NRS as is appropriate for chronic, as opposed to acute, pain.