Is fibromyalgia frequency increasing in axial spondyloarthritis? Association with fibromyalgia and biological therapies

Fibromyalgia (FM) is known a common painful syndrome and its frequency is increased in inflammatory rheumatic diseases. We aimed to assess FM frequency in axial spondyloarthritis (AxSpA) patients and age- and sex-matched healthy controls with the 2011 ACR FM criteria. We evaluated the association between receiving biologic disease-modifying antirheumatoid drugs (bDMARD) and presence of FM. 127 patients with Ax-SpA and 73 age- and sex-matched controls were included. Individuals were assessed according to modified 2011 ACR diagnostic criteria for FM. The pain was evaluated by visual analog scale (VAS). Disease activity was assessed by Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activation Score (ASDAS). Spinal limitation, quality of life, and functionality were assessed. Drug therapies were noted. AxSpA and control group had similar FM rates. 43 (33.9%) patients in AxSpA group and 22 (30.1%) patients in control group had FM diagnosis (p = 0.589). Age, gender, BMI, and CRP values were similar in the AxSpA patients with and without FM, while global VAS and ASDAS scores were higher in patients with FM. Biologic DMARD use was higher in the AxSpA patients with FM; however, the difference was not statistically significant. In conclusion, FM frequency does not increase in AxSpA patients as compared to healthy controls. FM awareness is one of the key points to determine the appropriate treatment due to the influence on disease activity.