RESEARCH - Fibromyalgic RA and disease assessment

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Rheumatology Advance Access published online on January 25, 2010

Rheumatology, doi:10.1093/rheumatology/kep458

Fibromyalgic rheumatoid arthritis and disease assessment

Louise C. Pollard1, le H. Kingsley1, Ernest H. Choy1 and L. 1

1Department of Rheumatology, King’s College London, School of Medicine

at Guy’s, King’s College and St ’ Hospitals, Weston Education

Centre, London, UK.

Abstract

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.

http://rheumatology.oxfordjournals.org/cgi/content/abstract/kep458v1?papetoc

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