Background: Rheumatoid arthritis [RA] is a type of progressive disease characterised by inflammation in the synovial tissues resulting in deformity and functional impairment. Fibromyalgia [FM] is a well-known comorbidity in RA which may change the physical evaluation and incorrectly affect the degree of RA treatment.  
The Aim of the work: To evaluate FM in patients with RA and its impact on disease activity, functional, and psychological status.
Patients and methods: The study included 1200 patients with RA. Individuals were divided based on their FM status. All patients were assessed clinically and evaluated by the Health Assessment Questionnaire for pain [HAQ-pain], the Multidimensional Assessment of Fatigue [MAF], the Pittsburgh Sleep Quality Index [PSQI], the Beck Depression Inventory-II [BDI-II], and the Modified Health Assessment Questionnaire for functional disability [MHAQ]. The Disease Activity Score with ESR [DAS28-ESR] was used to assess RA disease activity in 28 joints. FM and RA were diagnosed using the criteria of the American College of Rheumatology [ACR].
Results: Among our patients with RA, the prevalence of FM was 37%. Patients with FM had an increased proportion of females, were older, had a more prolonged disease duration, and had more protracted morning stiffness than patients without FM. Scores of DAS28 were considerably higher in RA patients with FM in comparison to those with only RA [5.70 ±1.19, 4.48 ± 1.26; P < 0.001] respectively. Concurrent FM also had worse HAQ-pain, MHAQ, fatigue, and depression scores, as well as more frequent sleep problems.
Conclusion: In patients with RA, coexisting FM was associated with greater activity of the disease and impairments in functional level. FM was linked to higher rates of depression and fatigue, as well as an increased prevalence of sleep problems. The recognition and evaluation of such psychiatric disorders may help patients with RA achieve therapeutic improvement or remission.