Cigarette Smoking in Patients With Systemic Sclerosis

Objective. To determine the effects of cigarette smoking on vascular, gastrointestinal, and respiratory outcomes in patients with systemic sclerosis (SSc). Methods. Subjects were patients enrolled in the Canadian Scleroderma Research Group cohort. Smoking history was obtained by patient self-report. The effect of smoking was assessed using multiple regression analysis of each SSc clinical outcome of interest (vascular, gastrointestinal, and respiratory). Smoking was modeled both as categorical variables (current, past, and never) and using the Comprehensive Smoking Index (CSI), which integrates smoking intensity, duration of smoking, and time since cessation into a single covariate of smoking effect. All regression models were adjusted for age, sex, disease duration, and limited or diffuse skin involvement. Results. This study included 606 patients with SSc, of whom 87% were women and 90% were white, and the mean age was 55 years, mean disease duration was 11 years, and 36% had diffuse disease. Of these patients, 16% were current smokers, 42% were past smokers, and 42% were never smokers. The regression analyses showed that smoking had a significant negative effect on almost all vascular, gastrointestinal, and respiratory outcomes. The effects of smoking were in some cases long-lasting (e. g., persistent respiratory abnormalities), and smoking cessation appeared beneficial with respect to some outcomes (e.g., reduced severity of Raynaud's phenomenon). Conclusion. Physicians caring for patients with SSc should prioritize smoking cessation as a recommendation to patients, and resources directed to supporting smoking cessation in patients with SSc should be more readily available.