A traditional view of pain in rheumatoid arthritis and osteoarthritis as primarily nociceptive and driven by inflammatory activity or structural damage may be oversimplified, based on findings published in the journal ACR Open Rheumatology. Juan Schmukler, MD, of Rush University Medical Center, Chicago, and colleagues reported that patients with these conditions also appear affected by neuropathic pain related to central or peripheral nervous system pathology, as well as nociplastic pain associated with pain sensitization.

According to the researchers, "the most widely used, and perhaps most sensitive, quantitative measure of pain is a simple 0 to 10 Visual Analog Scale or Visual Numeric Scale." The Visual Analog Scale (VAS) and Visual Numeric Scale (VNS) were used throughout the analysis. A selective review previously reported similar VNS pain scores of 4 to 6 over four decades (1979 to 2019), according to the researchers. The current narrative review updates that study with data published through 2024, "which depict dramatic reduction in swollen joints in RA but continued similar 0 to 10 pain VNS scores in rheumatoid arthritis (RA) and osteoarthritis (OA), as well as in other rheumatic diseases."

Pain and Routine Assessment of Patient Index Data 3 (RAPID3; a composite of physical function, pain, and patient global assessment) scores were also analyzed in patients with primary diagnoses of RA and OA based on whether patients screened positive or negative for anxiety, depression, and/or fibromyalgia on Multidimensional Health Assessment Questionnaire (MDHAQ) indices, which show approximately 80% agreement with reference questionnaires. The researchers noted, "Although anxiety, depression, and fibromyalgia have been recognized for decades as more prevalent in RA and OA than in the general population, most routine care does not include formal screens for these comorbidities, which appears feasible on the MDHAQ, completed by most patients in 5 to 10 minutes."

Key Findings

The researchers presented five observations regarding VAS and VNS scores in routine care patients with primary diagnoses of RA or OA over 45 years (1979 to 2024):

• In RA, median swollen joint counts out of 28 assessed joints declined from 12 in 1985 to 0 in two databases from 2021 and 2022; despite this improvement, they reported median pain VNS scores of 5 in both databases, comparable to a 1979 report.
• In OA, mean or median pain VAS/VNS scores were 4 to 6 in 1979 and appeared unchanged in 2022, comparable to findings in RA.
• RAPID3 scores were also found to be unchanged in both RA and OA from 1985 to 2022.
• Similar VAS/VNS pain scores of 4 to 6 were observed across other rheumatic diseases.
• Patients with RA or OA who screened positive for anxiety, depression, and/or fibromyalgia on MDHAQ indices had statistically significantly higher pain scores than those who screened negative.

The researchers concluded, "The data presented are only hypothesis-generating rather than hypothesis-testing but may suggest a possible paradigm shift in understanding of pain in rheumatic diseases. Further study of nociplastic pain in all rheumatic diseases, even when apparently 'explained' by nociceptive pain, may result in improved understanding and treatment of musculoskeletal pain in millions of people."

Disclosure: The study was supported in part by Medical History Services, LLC. For full disclosures of the researchers, visit acrjournals.onlinelibrary.wiley.com.

Source: ACR Open Rheumatology