Psoriatic arthritis (PsA) and spondyloarthritis (SpA) are chronic inflammatory conditions that cause progressive joint damage and disability. Apart from causing swelling and pain in multiple joints and entheseal sites, they are associated with fatigue, emotional effects, and poor health-related quality of life (HRQOL). Fibromyalgia (FM) is a chronic condition probably related to variations in central pain processing1 and is characterized by widespread bodily pain associated with somatic symptoms including fatigue and sleep disturbance. These manifestations of FM may overlap with those of PsA and SpA. It is also well known that FM may coexist with various rheumatic diseases. For example, the prevalence of FM among patients with rheumatoid arthritis (RA), systemic lupus erythematosus, and Sjögren syndrome was higher than that expected in the general population2.
In this issue of The Journal, Wach, et al3 and in a recent issue, Brikman, et al4, described the coexistence of FM in 17.8% of PsA and 17.5% of SpA patients, respectively. Women had a higher prevalence of concomitant FM in both conditions. Patients who had concomitant FM-PsA or FM-SpA in these studies had worse disease activity scores. Wach, et al also demonstrated that outcome measures [Ankylosing Spondylitis Disease Activity Score–C-reactive protein (ASDAS-CRP)] that incorporated objective measurement of systemic inflammation (CRP) were less influenced by concomitant FM. Symptoms of FM-like bodily pain and fatigue can mimic disease activity, while objective biomarkers of inflammation are less likely to be falsely positive and may thus reflect disease activity more accurately.
These findings were consistent with another study in axial PsA and ankylosing spondylitis, which reported that the version of ASDAS that incorporated both CRP and erythrocyte sedimentation rate (ESR) was superior in distinguishing the overall health status to the purely patient-reported Bath Ankylosing Spondylitis Disease Activity Index5. These …
Address correspondence to Dr. Y.Y. Leung, Department of Rheumatology and Immunology, Singapore General Hospital, The Academia, level 4, 20 College Road, Singapore 169856. E-mail: katyccc{at}hotmail.com
In this issue
