Fibromyalgia symptoms weakly predict RA activity after treatment

Higher levels of fibromyalgia (FM) symptoms in patients with rheumatoid arthritis (RA) are slightly indicative of worse disease activity following treatment with a disease-modifying antirheumatic drug (DMARD), suggest the results a recent study.

A group of researchers followed 192 patients with active RA for 12 weeks after initiation or change of DMARD therapy. Participants completed the Fibromyalgia Survey Questionnaire (FSQ) at the first visit. RA disease activity was evaluated by measuring the Disease Activity Score in 28 joints using C-reactive protein (DAS28-CRP) at baseline and follow-up.

The research team explored the relationship between baseline FSQ score and follow-up DAS28-CRP. In the secondary analysis, they evaluated the association between the two components of the FSQ, the Widespread Pain Index (WPI) and Symptom Severity Scale (SSS), with follow-up DAS28-CRP. They also conducted multiple linear regression analyses, with adjustments for clinical and demographic variables.

Multiple linear regression models showed the independent association of FSQ score with elevated DAS28-CRP scores 12 weeks following DMARD initiation (B, 0.04; p=0.01). Secondary analyses revealed the significant association of WPI (B, 0.08; p=0.001), but not SSS (B, ‒0.03; p=0.43), with increased follow-up DAS28-CRP scores.

“The primary factor that informed the FSQ’s prediction of disease activity was the spatial extent of pain, as measured by the WPI,” the researchers said.