The brief pain inventory-Interference Subscale has acceptable reliability but questionable validity in acute back and neck pain populations

Caitlin M P Jones; Chung-Wei Christine Lin; Joshua Zadro; Arianne Verhagen; Mark Hancock; Raymond Ostelo

doi:10.1016/j.bjpt.2024.101150

The brief pain inventory-Interference Subscale has acceptable reliability but questionable validity in acute back and neck pain populations

Braz J Phys Ther. 2024 Nov 21;28(6):101150. doi: 10.1016/j.bjpt.2024.101150. Online ahead of print.

Authors

Caitlin M P Jones¹, Chung-Wei Christine Lin², Joshua Zadro², Arianne Verhagen³, Mark Hancock⁴, Raymond Ostelo⁵

Affiliations

¹ Sydney Musculoskeletal Health, The University of Sydney, The Institute for Musculoskeletal Health, Sydney Local Health District, Level 10 N KGV Building, Missenden Rd, Camperdown 2050, Sydney, NSW, Australia. Electronic address: Caitlin.jones@sydney.edu.au.
² Sydney Musculoskeletal Health, The University of Sydney, The Institute for Musculoskeletal Health, Sydney Local Health District, Level 10 N KGV Building, Missenden Rd, Camperdown 2050, Sydney, NSW, Australia.
³ Graduate School of Health, University of Technology Sydney, Sydney, NSW, Australia.
⁴ Faculty of Medicine, Health and Human Sciences, Macquarie University Sydney, Sydney, NSW, Australia.
⁵ Amsterdam Movement Sciences Research Institute, Department of Health Sciences, Vrije University, Amsterdam, North Holland, the Netherlands; Department of Epidemiology and Data Science, Amsterdam UMC, Vrije Universiteit, Amsterdam, North Holland, the Netherlands.

PMID: 39577106
DOI: 10.1016/j.bjpt.2024.101150

Abstract

Background: The Brief Pain Inventory-Interference Subscale (BPI-IS) is a subscale of the BPI assessment tool developed to rapidly assess the impact of a person's pain on their function. It is uncertain whether it has one or two factors, and whether it has acceptable clinimetric properties in a mixed spinal pain (back and/or neck) population.

Objectives: To determine the clinimetric properties of the BPI-IS in a population with mixed spinal pain.

Methods: We completed a clinimetric evaluation with a test-retest design, factor analysis, and hypothesis testing. We used data collected for a randomised clinical trial including a population presenting to primary care or emergency departments with acute spinal pain (back and/or neck).

Results: Confirmatory factor analysis better supported the two-factor model of the BPI-IS (physical interference factor and affective interference factor) as compared to the one-factor model. Both one and two-factor models had acceptable reliability (high internal consistency and no evidence of floor or ceiling effects). Both models failed to reach our a-priori thresholds for acceptable construct (cross sectional) validity, and responsiveness (longitudinal validity) in either back or neck pain populations.

Conclusion: The BPI-IS has two factors and both have acceptable reliability, but tests for validity did not reach our a priori thresholds for acceptability (construct validity and responsiveness). The BPI-IS may not be suitable to measure the impact of pain on function in back and neck pain populations.

Keywords: Back pain; Brief pain inventory; Clinimetric; Functional impairment; Interference subscale; Neck pain.