Persistence of mild, early inflammatory arthritis: the importance of disease duration, rheumatoid factor, and the shared epitope.
OBJECTIVE: To determine the factors that predict clinical outcome at 6 months for patients with mild, early inflammatory arthritis. METHODS: Sixty-three patients with mild, untreated, early arthritis were given a single dose of corticosteroids at presentation. Administration was intramuscular if disease was polyarticular (n = 53) or intraarticular if patients had <5 synovitic joints (n = 10). The primary outcome measure was clinical disease remission or persistence of arthritis at 6 months following injection. RESULTS: At 6 months following injection, 49 of the 63 patients (78%) had persistent inflammatory joint disease. The other 14 (22%) had clinical disease remission. Regression analysis showed that only disease duration was significantly associated with persistent arthritis (P < 0.05). The other significant factor (by chi-square test) was the presence of the shared epitope (SE). Of the patients fulfilling the American College of Rheumatology (ACR) criteria at presentation (51% of the total), 53% with disease duration of < or = 12 weeks at presentation had persistent disease 6 months later, compared with 94% of those who presented with disease duration of >12 weeks. CONCLUSION: The strongest predictor of persistent disease was a disease duration of >12 weeks. Rheumatoid factor and SE were also predictors to a lesser extent. Patients who both fulfilled the ACR classification criteria for rheumatoid arthritis (RA) and had a short disease duration included some with an excellent prognosis. Therefore, 12 weeks may be a more appropriate disease duration to use for the RA classification criteria. Administering a bolus of corticosteroids may be a useful diagnostic/therapeutic approach.