The nosology-taxonomy of recent-onset arthritis: The experience of early-arthritis clinics

Objective: To compare the conclusions of studies addressing the outcome of early-arthritis cohorts. Methods: The methodologies of previous reports on early-arthritis cohorts w ere examined, and their results and conclusions were compared. Results: Thirty-four reports on 23 cohorts of early arthritis were found. T he methodology was poor in most studies, with numerous inclusion and exclus ion biases, frequently short follow-up periods, and a lack of precision abo ut the rationale for diagnosis. However, similar conclusions were reached o n several points: a large number of cases of early arthritis remained undif ferentiated and/or resolved spontaneously, about 80% of cases initially cla ssified as undifferentiated or rheumatoid arthritis retained this diagnosis during followup, and the incidence of psoriatic arthritis in most studies was similar (2% to 4%). Conversely, there were striking discrepancies among studies concerning the frequency of crystal arthropathies (0% to 18%), spo ndyloarthropathy (1% to 33%) and rheumatoid arthritis (15% to 47%), Conclusions: There appears to be a lack of agreement among researchers abou t the nosology and/or taxonomy of many cases of mild arthritis, despite the existence of classification criteria. Relevance: Recognition of cultural bias in the diagnosis of early arthritis could be a prerequisite for the optimization of new sets of criteria for t he diagnosis of early rheumatoid arthritis and spondyloarthropathy, Semin A rthritis Rheum 30:354-365. Copyright (C) 2001 by W.B. Saunders Company.