To study the effect of disease duration and smoking on outcome in early rheumatoid arthritis (RA).
Between 1996 and 2004, 1587 patients were included in the BARFOT early RA (disease duration ≤ 1 year) study in Sweden. European League Against Rheumatism (EULAR) response, Health Assessment Questionnaire (HAQ), rheumatoid factor (RF), and antibodies to cyclic citrullinated peptide (anti-CCP) were recorded at study start and at 3, 6, and 12 months.
In total, 180 RA patients (11%) had disease duration ≤ 12 weeks. These patients achieved good EULAR response significantly more often at 3 and 12 months than patients with a longer disease duration despite having more aggressive disease [EULAR good response was achieved by 35% and 35% at 3 and 12 months, respectively, among the patients with disease duration ≤ 12 weeks, by 35% and 41% of patients with disease duration of 13-24 weeks, and by 28% and 33% of patients with disease duration of 25-52 weeks (p = 0.02 for 3 months; p = 0.02 for 12 months)]. There was a significant correlation between improvement in Disease Activity Score-28 (DAS28), its individual variables, and Health Assessment Questionnaire (HAQ) and disease duration up to 12 months after study start. For smokers, no such trend was seen.
Up to 12 months after inclusion in the study, there was a significant correlation between improvement in DAS28, its individual components, and HAQ and disease duration, with patients who had a shorter disease duration improving most. Smokers had poorer EULAR response and showed no improvement with regard to disease duration.