There may be an association between comorbid fibromyalgia and poorer response to biologics in patients with inflammatory rheumatic diseases, according to study results published in Rheumatology International. Fibromyalgia was also associated with increased rheumatic disease activity and poorer quality of life.
Investigators performed a literature search of PubMed/MEDLINE, Cochrane, and Web of Science databases for English language articles published between 2014 and 2019 on fibromyalgia and inflammatory rheumatic diseases in adult patients. All articles on juvenile disease, including meta-analyses, letters to editors, commentaries, and abstracts were excluded from the study. From the selected studies, researchers extracted the following: prevalence of fibromyalgia in inflammatory rheumatic diseases, effect of fibromyalgia on patient response to biologic disease-modifying antirheumatic drugs (bDMARDs), mechanisms of interaction between bDMARDs and fibromyalgia, and effect of bDMARDs on fibromyalgia symptoms.
Data from literature indicated an increased prevalence of fibromyalgia among patients with inflammatory rheumatic disease compared with the general population. Fibromyalgia prevalence estimates varied significantly between studies, and rates in patients with spondyloarthritis ranged from 11.1% to 38.4%. Studies reporting prevalence rates identified female sex, lower educational status, higher disease activity, and higher enthesitis score as significant risk factors for comorbid fibromyalgia. Fibromyalgia was also associated with worse disease activity, poorer global health status, and decreased quality of life.
In 8 studies assessing treatment response, fibromyalgia was a significant predictor of not achieving remission with DMARD treatment and of increased biologic therapy use. The influence of fibromyalgia on drug response was primarily attributed to interaction with disease activity. Many studies have highlighted the limitation of traditional disease activity measures. Patients with fibromyalgia may indicate that they have more severe rheumatic symptoms, which can result in unnecessary modification of DMARD treatment schedules. Fibromyalgia has also been associated with peripheral and central neuroinflammation, which may play a role in the inflammatory state of rheumatic disease; however, data regarding the contribution of comorbid fibromyalgia to overall inflammation are inconclusive. Some studies indicated that bDMARD treatment may attenuate fibromyalgia symptoms in patients with rheumatic diseases, although further research is necessary to confirm these effects.