The Effect of Fibromyalgia on Disease Activity in Patients with Rheumatoid Arhritis Objective: The aim of the study is to determine the effect of fibromyalgia (FM) on disease activity and quality of life in patients with rheumatoid arthritis (RA). Methods: This was a randomized and prospective study conducted in 96 RA patients admitted to our rheumatic diseases outpatient clinic, diagnosed ac- cording to the American College of Rheumatology (ACR) 1987 criteria at least for 2 years. Data composed of demographical properties, painful and swollen joints, duration of morning stiffness, level of pain by Visual Analog Scale (VAS), number of used disease-modifying antirheumatismal drugs (DMARDs), and disease duration of all patients. In addition C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), rheumatoid factor (RF), and anticyclic citrul- linated peptide (anti-CCP) levels were measured. Disease Activity Score 28 (DAS28) was used to assess disease activity and Health Assessment Questionnaire (HAQ) and short form (SF-36) were used to assess the quality of life. FM diagnosis was primarily made on the basis of the ACR 1990 FM criteria. After then, two groups were generated as FM-positive and FM-negative patients. Disease activity (DAS28), quality of life (HAQ and SF-36), morning stiffness durations, numbers of painful and swollen joints, pain levels by VAS, number of DMARDs used, duration of disease, and laboratory diagnosis as well as activity parameters (CRP, ESR, RF, and anti-CCP) were compared between the two groups. Results: There was no significant difference in the duration of morning stiffness, duration of disease, number of used DMARDs, CRP, ESR, RF, and anti-CCP (p>0.05) between the two groups. RA patients with FM showed significantly higher scores of VAS, HAQ, and DAS28 and more painful joints than RA patients without FM; SF 36 scores were significantly lower in FM patents (p<0.05). Conclusion: FM adversely affects disease activity and quality of life in patients with RA. It may be help full to consider FM while evaluating disease activity in RA patients. Keywords: Fibromyalgia, rheumatoid arthritis, disease activity, quality of life Introduction Rheumatoid arthritis (RA), the etiology of which is not completely known and which begins with pathological changes of synovial tissues, primarily results in the destruction of peripheral joints and tissues characterized with chronic polyarticular joint involvement, and it is a systemic inflam- matory autoimmune disease (1-3). The most important impacts of RA on patients are persistent pain and functional impairment caused by synovitis and progressive joint damage (3). Because of the chronic course of the disease and functional insufficiency caused by the disease, the patients’ physical, emotional, and social functions are affected from the early stages of the disease and functional insufficiency and decrease in the quality of life occurs (4, 5). Fibromyalgia syndrome (FMS), the etiology of which is not certain, is a rheumatic disease char- acterized with widespread body pain, tenderness at specific anatomic regions, decreased pain threshold, sleep disorders, fatigue, and frequent associations with psychological distress (6). Al- though the etiology and mechanisms of FM are not fully understood, the most important factors for its emergence seem to be charecterized by neuroendocrine dysfunction, central pain mecha- nisms, and central sensitization (7). Although there is widespread musculoskeletal pain, physi- cal examinations, laboratory findings, and radiological examinations are normal. The disease is mostly seen in women between 40 and 50 years of age (8). Although there is no objective evidence such as inflammation and joint damage, FM can reduce the quality of life to a similar extent as RA. A study conducted by Sivas et al. (9) revealed that FM, which is not an inflammatory disease, could lead to high Disease Activity Scores (DAS) 28 because of the subjective symptoms such as tenderness and pain (9). The aim of the study was to determine the effect of FM on disease activity and the quality of life in patients with in patients with RA. Abstract Ahmet Bal, Nil Sayıner Çağlar, Sibel Çağlar Okur, Türkan Akın, Ebru Aytekin, Esra Çetin, Yasemin Pekin Doğan, İbrahim Halil Erdem, Özcan Ayşar Clinic of Physical Medicine and Rehabilitation, İstanbul Training and Research Hospital, İstanbul, Türkiye Address for Correspondence: Nil Sayıner Çağlar, İstanbul Eğitim ve Araştırma Hastanesi, Fiziksel Tıp ve Rehabilitasyon Kliniği, İstanbul, Türkiye Phone: +90 532 264 25 81 E-mail: nilcag@yahoo.com Received: 12.08.2014 Accepted: 27.12.2014 © Copyright 2015 by Available online at www.istanbulmedicaljournal.org Original Investigation İstanbul Med J 2015; 16: 18-22 DOI: 10.5152/imj.2015.75436