The Painful Truth: The Relationship between Non-Articular Pain and Patient Global Assessment before and after Initiating a New DMARD for Active Rheumatoid Arthritis.

Abstract

Objectives: Non-articular pain (NAP) may contribute to patient global assessment (PtGA), confound disease activity assessment, and influence treatment decisions. Our aims were to 1) evaluate the association between NAP and PtGA in adults with active RA starting a new DMARD; and 2) determine the extent this relationship is mediated by pain intensity.

Methods: We enrolled adults with active RA initiating a new DMARD. Participants indicated NAP on a body pain diagram (0-19 sites) and completed assessments of PtGA and pain intensity. To evaluate the association between NAP and PtGA, adjusted multivariable linear regression was performed. Mediation analyses using linear regression models examined whether this association was mediated by pain intensity, at baseline and 3-months separately. All models were adjusted for potential confounders.

Results: The 197 participants were mostly female (83.8%) with mean (sd) age of 55.1 (14.4) years, disease duration of 10.6 (12.6) years, and CDAI of 23.9 (14.6). NAP was reported by 92.9% at baseline, and 84.8% at 3-months. At baseline, each site of NAP (0-19) was associated with a 0.20-point higher PtGA (β = 0.20, 95% confidence interval (0.12-0.28). Pain intensity mediated 61.8% of this association. Similar findings were observed at 3-months.

Conclusion: There was a significant linear relationship between NAP and PtGA, most of which could be explained by pain intensity. These findings raise awareness of NAP and its added burden of worse perceived health status in RA. This may help prevent unnecessary DMARD treatment changes and increase specificity in treatment of different pain types.