Objective: To identify disease activity, smoking, and reproductive-related predictors of a poor prognosis in patients with very early inflammatory polyarthritis (IP).
Methods: Patients with very early IP (symptom duration 4-11 weeks) included in our study were participants in the STIVEA (Steroids In Very Early Arthritis) randomized placebo-controlled trial. At baseline, disease-related variables were measured and patients were asked to complete a questionnaire covering smoking status and reproductive questions. Baseline predictors of poor prognosis [i.e., the need to start disease-modifying antirheumatic drug (DMARD) therapy by 6 months or the clinical diagnosis of rheumatoid arthritis (RA) at 12 months] were identified, applying logistic regression analyses adjusted for treatment group.
Results: Rheumatoid factor (RF) positivity was one of the strongest clinical predictors of a poor prognosis: OR for DMARD therapy at 6 months, 4.00 (95% CI 2.00-8.00) and OR for a diagnosis of RA at 12 months, 9.48 (95% CI 4.48-20.07). There was a significant association between current smoking at baseline compared to never smoking and a diagnosis of RA at 12 months (OR 3.15, 95% CI 1.16-8.56).
Conclusion: About 6 in 7 patients with very early RF-positive IP were diagnosed with RA 1 year later. In addition, 1 in 4 IP patients who smoke will develop RA later. It is recommended to treat RF-positive patients who have IP with DMARD at presentation and to advise patients to stop smoking.