RESUMEN
Our objective was to analyze the effects of cigarette smoking on disease activity, functional capacity, radiographic damage, serology and presence of extraarticular manifestations in patients with rheumatoid arthritis and undifferentiated arthritis. This is a cross-sectional study of 1,305 patients (729 with rheumatoid arthritis and 576 with undifferentiated arthritis) from CONAART, the Argentine Consortium for Early Arthritis that includes patients older than 16 years with <2 years of disease. Sociodemographic data, clinical characteristics of the disease and smoking history were collected. In patients with rheumatoid arthritis the disease activity score of 28 joints was 5.4 ± 1.3 in current smokers, 5.2 ± 1.4 in former smokers and 5.1 ± 1.4 in never smokers (p = 0.011). The simple erosion narrowing score was higher in current smokers and former smokers than in never smokers (M 14.0, R Q 6.0-21.0; M 15.0, R Q 7.0-24.0; M 10.0, R Q 5.0-17.0; p = 0.006). Current smokers had higher rheumatoid factor titer (M 160.0, R Q 80.0-341.0) than former smokers (M 146.8, R Q 6.03-255.5) and never smokers (M 15.0, R Q 9.0-80.0) (p = 0.004). The variable independently associated with tobacco exposure was simple erosion narrowing score (OR = 1.03, 95 % CI 1.00-1.05; p = 0.012). In patients with undifferentiated arthritis, an association between smoking status and parameters of activity or radiographic damage was not observed. Neither was tobacco exposure related to the presence of extraarticular manifestations or to the degree of disability in any of the two groups of patients. No relation was found between disease activity and severity, and number of packs smoked per year. Tobacco.