The Painful Truth: The Relationship Between Nonarticular Pain and Patient Global Assessment Before and After Initiating a New Disease-Modifying Antirheumatic Drug for Active Rheumatoid Arthritis.

Abstract

Nonarticular 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 rheumatoid arthritis (RA) starting a new disease-modifying antirheumatic drug (DMARD) and (2) determine the extent to which this relationship is mediated by pain intensity. 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 at three months separately. All models were adjusted for potential confounders. The 197 participants were mostly female (83.8%), with a mean age of 55.1 (SD 14.4) years, a mean disease duration of 10.6 (SD 12.6) years, and a mean Clinical Disease Activity Index score of 23.9 (SD 14.6). NAP was reported by 92.9% at baseline and by 84.8% at three 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 three months. 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.