Fibromyalgic rheumatoid arthritis and disease assessment

• Published in: Rheumatology (Oxford, England) Vol. 49; no. 5; pp. 924 - 928
• Main Authors: Pollard, Louise C., Kingsley, Gabrielle H., Choy, Ernest H., Scott, David L.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.05.2010
• Subjects: Adult; Aged; Aged, 80 and over; Antirheumatic Agents - therapeutic use; Arthritis, Rheumatoid - drug therapy; Arthritis, Rheumatoid - physiopathology; Biological and medical sciences; Cohort Studies; DAS-28; Diseases of the osteoarticular system; Fatigue; Fatigue - drug therapy; Fatigue - etiology; Female; Fibromyalgia - drug therapy; Fibromyalgia - physiopathology; Humans; Inflammatory joint diseases; Joints; Male; Medical sciences; Middle Aged; Pain - drug therapy; Pain - etiology; Rheumatoid arthritis; Severity of Illness Index; Tender points; Young Adult; Immunopathology; Chronic; Rheumatoid arthritis; Diseases of the osteoarticular system; Rheumatology; Autoimmune disease; Fatigue; Inflammatory joint disease; Tender points; DAS-28
• ISSN: 1462-0324; 1462-0332
• DOI: 10.1093/rheumatology/kep458

Objective. We evaluated fibromyalgic RA to determine its clinical impact, identification using core clinical assessments and influence identifying active disease using disease activity scores (DAS-28). Methods. We examined the impact and identification using core clinical assessments (tender minus swollen joint counts) of fibromyalgic RA (⩾11 tender points) in initial (105 patients) and replicate (100 patients) cohorts. Receiver operator characteristic (ROC) curves optimized the cut-off points using tender minus swollen joint counts; their validity was confirmed in a routine practice cohort (321 patients). We evaluated whether fibromyalgic RA affected the identification of active disease using DAS-28 (⩾5.1) and the clinical disease activity index (CDAI). Results. A total of 18/105 and 12/100 patients in initial and replicate cohorts, respectively, had fibromyalgic RA. This was identified by ⩾7 tender minus swollen joint counts with 83% sensitivity and 80% specificity in the initial cohort (72 and 98% in replicate, respectively) and ROC area under the curve 0.80 (0.94 in replicate). ‘Fibromyalgic’ RA (tender point scores in initial and tender minus swollen joints in clinical practice cohorts) had higher DAS-28, pain, fatigue and HAQ scores. More fibromyalgic RA patients had active disease by DAS-28 (odds ratio 14.3; 95% CI 5.5, 37.1; and CDAI 17.2; 95% CI 6.1, 48.5); conventional assessments (three or more tender joints; three or more swollen joints; ESR ⩾28 mm/h) showed no difference (1.75; 95% CI 0.72, 4.3). Conclusion. Fibromyalgic RA affects 12–17% of RA outpatients and results in worse functional outcomes. DAS-28 scores over-interpret active disease in fibromyalgic RA.