Disease activity score in rheumatoid arthritis with or without secondary fibromyalgia

To correlate disease activity score (DAS-28) in the patients with rheumatoid arthritis (RA) with and without secondary fibromyalgia.

Comparative cross-sectional study.

Department of Rheumatology, Pakistan Institute of Medical Sciences, Islamabad, from November 2011 to April 2012.

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.

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).

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.