Background Fibromyalgia (FM) is a multi-symptom syndrome characterized by chronic widespread pain, fatigue, and poor sleep quality. Some of these symptoms such as fatigue and disturb sleep seen in patients with rheumatoid arthritis (RA). Moreover, FM and RA can coexist creating a diagnostic challenge in rheumatology clinical practice and influence clinical decisions. Data on the prevalence of fibromyalgia in general population in Dubai 1.36%¹. There is scares of data on the prevalence of FM in RA in the Middle East. We took the opportunity to study the prevalence of FM in our cohort of RA patients

Objectives: To assess the prevalence of fibromyalgia among RA patients in our practice.

Methods: We explored the prevalence of FM in 575 adult RA patients fulfilling the 2010 ACR/EULAR classification Criteria for RA², attending the Rheumatology outpatient services in Dubai Hospital. Electronic Medical records (EMR) and medical files were reviewed for the occurrence of FM in the period from July 2017 to January 2018. We verified the documented diagnosis of FM using the 2016 revisions version of the 2010 ACR fibromyalgia classification criteria³. Grouping: Group 1 RA with FM, Group 2 RA without FM. A 2x2 contingency table (Fisher's exact test) was used to compare demographic, laboratory, drug use and biologics in both groups. Group 1 was further analyzed according to the drug used for FM.

Results: We identified fibromyalgia in 10.43% (60 out of 575) RA patient. FM in RA was predominately in females 58 (96.7%) versus male 2 (3.3%). Medications were used to control the symptoms of FM in 91.7% (55 of 60) and these were as follow Pregabalin (55%), Duloxetine (18.3%), Gabapentin (16.7%) and Amitriptyline (1.7%). Interesting, only 20% (12 out of 60) of patients had Vitamin D insufficiency. Five patients (8.3%) didn’t use specific drug for Fibromyalgia.

On comparing the two groups there was no difference in regards to demographic data, and clinical parameters including treatment. However, RA patients with FM were twice likely to use more biologics than RA patients without FM Odds Ratio= 2, though it did not reach statistical significance (P-Value= 0.16).

Conclusions: The prevalence of fibromyalgia is 10.4% among RA patients in Dubai Hospital. Ten times higher than the general population (historical control). Females are the predominant gender affected. Pregabalin is the most commonly used medication in this group.

Odds ratio showed that RA patients with FM are twice likely to use biologic DMARDs than RA patients without FM, although this trend didn't reach statistical significance. Indeed, fibromyalgia can affect clinical decision in RA. Further prospective studies are recommended in different cohorts to clarify the true effect size.

References: [1] Al Saleh J, Sayed ME, Monsef N, Darwish E. "The Prevalence and the Determinants of Musculoskeletal Diseases in Emiratis Attending Primary Health Care Clinics in Dubai." Oman Med J 2016;31(2):117-123.

[2] Aletaha D, Neogi T, Silman AJ, et al. 2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative Annals of the Rheumatic Diseases 2010;69:1580-1588.

[3] Wolfe F, Clauw D, Fitzcharles MA, et al. The American College of Rheumatology Preliminary Diagnostic Criteria for Fibromyalgia and Measurement of Symptom Severity. Arthritis Care Res 2010;62:600-10.

Disclosure of Interest: None declared