RESEARCH - Polymyalgia rheumatica can be distinguished from late onset RA at baseline

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Rheumatology Advance Access originally published online on November 2, 2008

Rheumatology 2009 48(2):123-127; doi:10.1093/rheumatology/ken343

Polymyalgia rheumatica can be distinguished from late onset rheumatoid

arthritis at baseline: results of a 5-yr prospective study

C. T. Pease1, G. Haugeberg1,2, B. Montague3, E. M. A. Hensor1, B. B.

Bhakta1, W. Thomson4, W. E. R. Ollier5 and A. W. 1

1Section of Musculoskeletal Disease, Leeds Institute of Molecular

Medicine, University of Leeds, Leeds, UK, 2Norwegian University of

Science and Technology, Trondheim, Norway, 3Transplant and Cellular

Immunology, St 's University Hospital, Leeds, 4ARC-EU, Stopford

Building and 5The Centre for Integrated Genomic Medical Research,

University of Manchester, Manchester, UK.

Abstract

Objective. To describe the pattern of arthropathy and HLA-DRB1 alleles

associated with PMR in order to develop a diagnostic algorithm that

could help distinguish PMR and RF-negative (RF –ve) late-onset RA

(LO-RA) at presentation.

Methods. This was a prospective study of all patients presenting with

PMR or LO-RA over a 10-yr period to one physician. Demographic,

clinical and laboratory data were collected at presentation and during

a minimum of 5 yrs of follow-up. The accuracy of the initial diagnosis

was systematically reviewed.

Results. One hundred and forty-two patients with LO-RA, 147 with PMR

and 42 with PMR + TA were studied. Peripheral synovitis was observed

in 23% of the PMR patients. In comparison with RF –ve LO-RA, PMR

patients were younger (P < 0.001), myalgia more frequent [100 vs 16%

(P < 0.001)] and arthritis of PIP, MCP and wrist were less frequent (P

< 0.001). The combination of wrist + MCP/PIP or wrist + PIP + MCP were

highly suggestive of RF –ve LO-RA (P < 0.001). HLA-DRB1*0101/0102 and

*0401 were significantly increased in PMR patients compared with

healthy controls. Plasma viscosity and arthritis in the wrist, in

combination with at least one MCP or PIP joint at disease onset, were

predictive of whether a non-erosive RF –ve patient would ultimately be

diagnosed as having RF –ve LO-RA or PMR (±/arthritis).

Conclusion. Our longitudinal follow-up data were consistent with RF

–ve LO-RA being a separate disease entity to PMR despite some

phenotypic and immunogenetic similarities at disease onset. A

diagnostic algorithm was derived using baseline clinical features to

predict the final diagnosis of RF –ve, non-erosive patients.

http://rheumatology.oxfordjournals.org/cgi/content/abstract/48/2/123

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