Fibromyalgia is common in patients with chronic inflammatory arthritis, and may affect optimal management and treatment of rheumatological disorders, a new U.K. study reports.
The study, “Concomitant fibromyalgia complicating chronic inflammatory arthritis: a systematic review and meta-analysis,” was published in the journal Rheumatology.
Patients with inflammatory arthropathies, which are diseases affecting the joints, commonly meet the criteria for fibromyalgia. However, both the prevalence of this dirsorder in inflammatory arthropathy and whether fibromyalgia is a complication or occurs independently are still unclear.
Regardless of what causes fibromyalgia in these patients, this condition may significantly affect the treatment of the inflammatory condition. Current rheumatological treatments aim to reduce disease activity or achieve disease remission.
As evaluation of disease activity is partially done by patients’ self-assessment, the presence of fibromyalgia may aggravate disease activity scores (DAS), thereby leading to inappropriate dose escalation, termination of therapy, or treatment choice.
The research team at University of Liverpool conducted a systematic review of the literature to assess the prevalence of fibromyalgia in adults with chronic inflammatory arthritis, including rheumatoid arthritis (RA), ankylosing spondylitis (AS), psoriatic arthritis (PsA), and axial spondyloarthritis (AxSpA). The scientists also compared DAS in patients with and without fibromyalgia.
The authors analyzed a total of 40 studies. Results revealed that the prevalence of fibromyalgia ranged from 4.9 to 52.4% in the 29 studies of RA; from 4.11 to 25.2% in the nine studies of AS and AxSpA; and from 9.6 to 27.2% in the six articles on PsA.
The scientists also conducted a meta-analysis — a type of statistical analysis combining the results of multiple studies — which indicated that the overall prevalence of fibromyalgia was 21% in RA, 13% in AS, and 18% in PsA. These differences reflect the diverse proportions of women affected by each condition, the authors said. Of note, women are markedly more affected by fibromyalgia than men.
Also, the data showed that patients with fibromyalgia had higher (worse) DAS in cases of RA, AS, and, to a lesser extent, in PsA. The differences in RA and AS were clinically important, the authors noted, as they could lead to starting or stopping treatment with potentially harmful and expensive medications.
Self-reported assessments of DAS, such as tender joint count and Visual Analogue Scale pain scores, appeared to be higher in the presence of fibromyalgia. This contrasted to results of objective assessments, including swollen joint count and laboratory markers of disease activity.
“This systematic review of 40 papers found that comorbid [fibromyalgia] is much more common in patients with RA, AxSpA or PsA than in the general population,” the researchers wrote.
“Comorbid [fbromyalgia] appears to amplify DAS and could therefore influence management of these rheumatic conditions,” they added.