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Psoriatic arthritis – definition and classification criteria. Philip Helliwell Senior Lecturer in Rheumatology University of Leeds. Psoriatic arthritis. Wright V Annals of Rheumatic Diseases 1961;20:123-132. Too sensitive?. Too specific?. Psoriatic arthritis – key individual features.
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Psoriatic arthritis – definition and classification criteria Philip Helliwell Senior Lecturer in Rheumatology University of Leeds
Psoriatic arthritis Wright V Annals of Rheumatic Diseases 1961;20:123-132
Too sensitive? Too specific?
Psoriatic arthritis – key individual features • Psoriasis • Symmetry • Rheumatoid factor
Psoriasis • May be hidden • May be coming • May have gone • May be in family • May be misdiagnosed
Symmetry in early and late psoriatic and rheumatoid arthritis
Psoriatic arthritis - the significance of rheumatoid factor • Moll and Wright excluded (usually) • Gladman (and others) included ( up to 15%) • Not unreasonable to allow RF as may just reflect a chronic inflammatory state • Need to: • Reliably exclude the seronegative rheumatoid arthritis • Reliably include the seropositive psoriatic arthritis
Rheumatoid factor • Could we make this test more specific? • Rheumatoid factor isotypes • Or use other tests? • Anti-perinuclear factor • Anti-CCP antibodies
Psoriatic arthritis –one disease or more? • Large joint mono/oligoarthritis • Entheseal disease (including spinal disease) • SAPHO/CRMO • DiP and mutilans • Symmetrical polyarthritis + Ps = RA?
Psoriatic arthritis – does it exist? • Cats believed psoriasis merely modifies inflammatory response • Immunogenetic data not all that convincing • Inflammatory response has an array of common pathways
Psoriatic arthritis – why bother? • BUT… • Nosology • Good and bad prognostic disease • Treatment outcome • Treatment indications • Same NSAIDs • Same DMARDs • Same biologics
Disability and quality of life in RA and psoriatic arthritis according to severity of arthritis
700 patients with psoriatic arthritis 700 controls with inflammatory arthritis and inflammatory OA Standardised proforma Clinical and historic data Radiographic data Genetic data Quality control Validation of classification criteria for psoriatic arthritis A prospective multi-centre international case control study
Analysis by: Conditional logistic regression Latent class analysis Classification and regression trees International study All major ‘players’ Consensus criteria Based on sound methodology Validation of classification criteria for psoriatic arthritis RESULTS AVAILABLE IN 2003 2004
What will CASPAR do? • Enable us all to use the same criteria • Distinguish between seronegative rheumatoid arthritis and psoriatic arthritis • Facilitate studies of • natural history • Treatment • immunogenetics
Psoriatic arthritis • Is a distinctive disorder • New criteria need to encapsulate this while not being exclusive • A distinctive (and preferably pathogenic) biologic marker would help