Prognostic Factors in a Large Cohort of Patients With Early Undifferentiated Inflammatory Arthritis After Application of a Structured Management Protocol

Abstract

Objective. Inflammatory arthritis of the hands is a frequent clinical presentation with a variable outcome. Patients not satisfying the classification criteria for recognized arthritides are described as having undifferentiated inflammatory arthritis, for which there are no accepted therapeutic algorithms. This study assessed the clinical outcome of patients with undifferentiated arthritis of the hands after use of a treatment algorithm, and evaluated the prognostic features in these patients. Methods. One hundred consecutive patients with undifferentiated arthritis of the hands were assessed following use of a pragmatic treatment algorithm that was based on clinical presentation and response to treatment. The following standard step-up treatment protocol was used: 1) nonsteroidal antiinflammatory drugs (NSAIDs), 2) a single dose of corticosteroid administered by either intramuscular or intraarticular injection, and 3) disease-modifying antirheumatic drugs (DMARDs). Patients with specific rheumatologic diagnoses were excluded. The primary outcome was persistence of synovitis at 12 months. Results. Seventy-eight percent of patients received NSAIDs, 72% received corticosteroids, and 30% received DMARD therapy. Among patients who had synovitis at 12 months, the prevalence of rheumatoid factor (RF) seropositivity, swollen joints, and synovitis at baseline was greater than in those without persistent synovitis. Logistic regression analysis showed baseline investigations to be poor predictors of subsequent DMARD use, with the best predictor being persistence of synovitis at 12 weeks. Rheumatoid arthritis (RA) developed in 14 patients. Logistic regression analysis showed that significant predictors of RA were RF seropositivity and the painful joint count at baseline. No patient who experienced resolution of synovitis by 12 weeks had persistent synovitis that subsequently required DMARD therapy. Only 13% of patients entered remission. Early resolution of synovitis was associated with an excellent prognosis. Conclusion. Undifferentiated arthritis of the hands is not a benign condition, with 30% of patients receiving DMARD therapy by 12 months and low remission rates. Results of the clinical assessment at 12 weeks is the single best predictor of future therapy. This study provides background data for use in determining future therapeutic interventions.