Journal of the College of Physicians and Surgeons Pakistan 2013, Vol. 23 (6): 413-417 413 INTRODUCTION Rheumatoid arthritis (RA) is a chronic polyarticular inflammatory disorder affecting the musculoskeletal system. It is a disabling disease which directly affects the quality of life. 1 Fibromyalgia (FM) is another common clinical syndrome which results from a defect in central pain processing. It is characterized by chronic, wide- spread musculoskeletal pain, fatigue, sleep disturbance, physical and psychological impairment. 2,3 Prevalence of fibromyalgia has been reported as 12 – 17% among rheumatoid arthritis patients compared to 2 – 5% in general population. 4,5 The term “fibromyalgic RA” has been introduced for RA patients having co-existing fibromyalgia. 6 Co-existent fibromyalgia is known to adversely affect the various disease indices used to measure rheumatoid arthritis disease activity like DAS-28, HAQ and SF-36. 7 DAS-28 has special importance in patients with RA while formulating their treatment decision regarding disease modifying drugs (DMARDs) and biologics, which are expensive therapies. 8,9 DAS-28 is known to over- estimate the disease activity in fibromyalgic RA. 10 If DAS scores are disproportionately high in relation to the actual level of synovitis as in fibromyalgic RA, DAS assessment becomes ambiguous. 11 In a developing country like Pakistan, various factors like socioeconomic and psychological may have an impact on perception and consequent disability of this disease. Associated fibromyalgia in RA patients may lead to over assessment of disease activity which can lead to unnecessary changes in the therapy. Therefore, the present study was conducted to determine the correlation of disease activity score (DAS) with and without fibromyalgia in the patients with rheumatoid arthritis. METHODOLOGY It was a cross-sectional study, patients were enrolled using non-randomized convenient sampling. Study was carried out in the Department of Rheumatology, Pakistan Institute of Medical Sciences, Islamabad, for a period of 6 months (November 2011 to April, 2012). Patients above 16 years of age, of either gender, diagnosed to have rheumatoid arthritis according to ACR/EULAR criteria, 2010, included in the study. Fibromyalgia was diagnosed by ACR 1990 criteria. Patients with other autoimmune diseases or who had psychiatric illnesses were excluded. A written consent ORIGINAL ARTICLE Disease Activity Score in Rheumatoid Arthritis with or without Secondary Fibromyalgia Shazia Zammurrad, Wajahat Aziz and Abid Farooqi ABSTRACT Objective: To correlate disease activity score (DAS-28) in the patients with rheumatoid arthritis (RA) with and without secondary fibromyalgia. Study Design: Comparative cross-sectional study. Place and Duration of Study: Department of Rheumatology, Pakistan Institute of Medical Sciences, Islamabad, from November 2011 to April 2012. Methodology: Patients aged above 16 years diagnosed to have rheumatoid arthritis according to ACR/EULAR criteria 2010 were included in the study. Fibromyalgia (FM) was diagnosed by ACR 1990 criteria. Patients of other autoimmune diseases or psychiatric illnesses were excluded. DAS was determined and compared using t-test with significance at p < 0.05. Results: The mean age of study subjects was 42.9 years. Thirty one out of total 138 patients had fibromyalgia (22.4%). Female gender was predominant (92.0%); being 96.8% in patients with and in 88.2% without fibromyalgia. The average DAS score was high (5.3 + 1.5) in fibromyalgia patients compared to those without fibromyalgia (3.9 + 1.2); this difference in mean value was statistically significant (p = < 0.001). Conclusion: DAS-28 is a useful tool for assessing rheumatoid arthritis disease status in outpatient setting, however, increased disease activity must be assessed for possible co-existence of fibromyalgia which can spuriously give high DAS value and adversely affect treatment decision. Key words: Rheumatoid arthritis. Fibromyalgia. DAS-28 score. Department of Rheumatology, Pakistan Institute of Medical Sciences, Islamabad. Correspondence: Dr. Shazia Zammurrad, 63-A, Officers’ Housing Society, Scheme No. 2, Tipu Road, Chaklala, Rawalpindi. E-mail: shaziazammurrad@hotmail.com Received: June 20, 2012; Accepted: March 11, 2013.