Background& Aim: Various musculoskeletal disorders, including Fibromyalgia syndrome (FMS), are seen in most patients undergoing hemodialysis. This research aimed to assess the frequency of fibromyalgia among hemodialyzed patients and its relation to quality of life, depression, anxiety, and laboratory investigations.

Methods: A case-control study involved 131 hemodialysis patients and 131 healthy controls attending Rheumatology & Nephrology departments, Zagazig University Hospitals, Egypt. Demographic and clinical characteristics, including age, sex, body mass index, & dialysis duration, and laboratory investigations were recorded. FMS was diagnosed using the 2010 American College of Rheumatology diagnostic criteria. Fibromyalgia Impact Questionnaire (FIQ), Beck Depression Inventory (BDI), and Beck Anxiety Inventory (BAI) were applied.

Results: Fibromyalgia frequency was significantly higher among controls than hemodialyzed patients (76.3% versus 22.9%, respectively). Hemodialyzed patients with FMS revealed significant associations between fibromyalgia and (moderate & severe anxiety), (mild mood disturbance & depression), abnormal C-reactive protein (CRP), anemia, normal parathyroid hormone, normal bone turnover, normal calcium, and normal Vitamin D (P≤0.001**, ≤0.001**, 0.001*, ≤0.001**, ≤0.001**, ≤0.001**, 0.009*, & 0.001*, respectively). About two-thirds (60%) of hemodialyzed patients with fibromyalgia had impaired quality of life. Among the hemodialysis group, FMS showed significant positive correlations with FIQ (r=0.911, P≤0.001**) & BDI (r=0.268, P=0.002*) and insignificant positive correlation with BAI (r=0.153, P=0.080).

Conclusion: The frequency of fibromyalgia is higher in healthy controls than in hemodialyzed patients. FMS in hemodialyzed patients shows significant associations with depression, anxiety, abnormal CRP, anemia, and normal bone minerals. There are positive correlations between fibromyalgia and FIQ & BDI scores among hemodialyzed patients.