Validity and contributions to pain from the central aspects of pain questionnaire in rheumatoid arthritis

Smith, Stephanie; Georgopoulos, Vasileous; Ifesemen, Onosi; James, Richard; Ferguson, Eamonn; Wakefield, Richard; Wilson, Deborah; Buckley, Philip; Platts, Dorothy; Ledbury, Susan; Choy, Ernest; Pickles, Tim; Rutter-Locher, Zoe; Kirkham, Bruce; Walsh, David; McWilliams, Daniel

Abstract

Introduction:

The central nervous system (CNS) contributes to pain perception across musculoskeletal conditions. The central aspects of pain (CAP) questionnaire captures a single score associated with quantitative sensory testing (QST) evidence of CNS dysfunction validated in knee osteoarthritis.

Objectives:

Given the different pathophysiology of rheumatoid arthritis (RA), an inflammatory polyarthritis, this cross-sectional study assessed CAP's psychometric properties and its association with pain in RA.

Methods:

Adults with RA were recruited from Nottinghamshire, London, and Cardiff. Participants completed CAP and reported pain using a numerical rating scale. A subgroup underwent additional assessments, including quantitative sensory testing (QST; Pressure Pain detection Threshold, Temporal Summation, Conditioned Pain Modulation), Disease Activity Score-28, C-reactive protein, questionnaires addressing pain and related characteristics, and Central Sensitization Inventory short form (CSI-9). Cronbach alpha, confirmatory factor (CFA), and Rasch measurement theory assessed CAP's reliability and validity. Multivariable linear regression modelled contributions to pain by inflammation indices and CAP or CSI-9.

Results:

The 380 participants (73% female, median 63 years) reported average pain over the past 4 weeks of 6/10 and a CAP score of 9/16. Central aspects of pain demonstrated acceptable reliability (ICC(2,1) = 0.71), CFA fit (comparative fit index = 0.99, Tucker–Lewis index = 0.99, root mean square error of approximation = 0.034, standardized root mean residuals = 0.03), and internal consistency (α = 0.82). Central aspects of pain was significantly associated with pain (0.50 ≤ β ≤ 0.57) but not QST. Central aspects of pain explained 33% of pain variance, rising to 42% with inflammation, age, sex, and body mass index. Central Sensitization Inventory-9 correlated with pain, not QST and explained less pain variance than CAP.

Conclusion:

Central aspects of pain is reliable and valid for use with people with RA and explains RA pain variance better than inflammation or CSI-9.

Citation

Smith, S., Georgopoulos, V., Ifesemen, O., James, R., Ferguson, E., Wakefield, R., Wilson, D., Buckley, P., Platts, D., Ledbury, S., Choy, E., Pickles, T., Rutter-Locher, Z., Kirkham, B., Walsh, D., & McWilliams, D. (2025). Validity and contributions to pain from the central aspects of pain questionnaire in rheumatoid arthritis. PAIN Reports, 10(4), Article e1295. https://doi.org/10.1097/PR9.0000000000001295

• Journal Article Type: Article
• Acceptance Date: Mar 30, 2025
• Online Publication Date: Jun 20, 2025
• Publication Date: 2025-08
• Deposit Date: Apr 3, 2025
• Publicly Available Date: Apr 3, 2025
• Journal: PAIN Reports
• Electronic ISSN: 2471-2531
• Publisher: Lippincott, Williams & Wilkins
• Peer Reviewed: Peer Reviewed
• Volume: 10
• Issue: 4
• Article Number: e1295
• DOI: https://doi.org/10.1097/PR9.0000000000001295
• Public URL: https://nottingham-repository.worktribe.com/output/47281422
• Publisher URL: https://journals.lww.com/painrpts/fulltext/2025/08000/validity_and_contributions_to_pain_from_the.19.aspx