Smoking at onset of rheumatoid arthritis (RA) and its effect on disease activity and functional status: experiences from BARFOT, a long-term observational study on early RA

Objectives: To assess the effects of smoking on disease outcome in a large cohort of patients with early rheumatoid arthritis (RA). Methods: Between 1996 and 2004, 1787 adult patients (disease duration <= 1 year) were included in the BARFOT early RA study in Sweden. Smoking status was recorded at inclusion in the study. Disease Activity Score using 28 joint counts (DAS28), C-reactive protein (CRP), Health Assessment Questionnaire (HAQ) score, rheumatoid factor (RF), antibodies to cyclic citrullinated peptide (anti-CCP), general health (GH) and pain visual analogue scales (VAS), and drug treatment were registered at inclusion and at follow-up at 3, 6, and 12 months. European League Against Rheumatism (EULAR) response and remission criteria were applied at 3, 6, and 12 months. Results: The proportion of patients who smoked at inclusion in the study fell from 29% in 1996 to 20% in 2004. There were no significant differences in disease activity at inclusion stratified according to smoking status. At 12 months of follow-up, 18% of current smokers at inclusion, 12% of previous smokers, and 11% of never smokers had high disease activity (DAS28 > 5.1, p = 0.005). Significantly fewer current smokers were in remission at 12 months (33%) compared to never smokers (36%) and previous smokers (42%) (p = 0.013). Current smoking at inclusion independently predicted poor EULAR response up to 12 months of follow-up. Conclusion: The present study gives some support to earlier data indicating that RA patients who smoke have a more active disease but further studies are needed to confirm this.