Comparison of pulmonary function, respiratory symptoms, functional level, and health-related quality of life in patients with systemic sclerosis according to smoking status

Background Patients with systemic sclerosis (SSc) are at high risk for pulmonary and vascular complications. Smoking is an important risk factor for respiratory symptoms and vascular complications of many diseases in the general population. However, studies on the role of smoking in SSc are insufficient. Aims This study aimed to compare pulmonary function, respiratory symptoms, functional level, and health-related quality of life (HRQoL) in patients with SSc according to smoking status and to assess the correlation between cigarette consumption and these parameters in patients with SSc. Methods Seventy-two patients with SSc (smoker group; n = 35 or nonsmoker group; n = 37) were included. The pulmonary function test was measured with a spirometer. Respiratory symptoms were questioned and the perceived severity of dyspnea and fatigue was evaluated. The functional levels were determined by questioning the patients' average daily walking distance, exercise habits, and daily sedentary time. HRQoL was assessed by Scleroderma Health Assessment Questionnaire. Results The rate of respiratory symptoms including dyspnea, cough, and sputum were higher in the smoker group (p .001, p = .041, and p .001, respectively). Also, the perceived severity of dyspnea and fatigue was higher in the smoker group (p < .05). The mean daily walking distance, exercise habits, and overall HRQoL were lower (p = .004, p = .002, and p = .034, respectively) and the sedentary time and vascular complications were higher (p .001 and p = .038, respectively) in the smoker group. However, there was no significant difference between the two groups in terms of the pulmonary function test (p > .05). There was a weak to moderate correlation between cigarette consumption and respiratory symptoms, dyspnea and fatigue severity, functional level, and HRQoL in the smoker group (0.001 <= p <= .024). Conclusions Smoking may increase respiratory symptoms and vascular complications and decrease the functional level and HRQoL in patients with SSc. To maintain functional independence in patients with SSc, awareness of the harms of smoking should be increased and smoking cessation should be encouraged, along with physiotherapy and rehabilitation programs including exercise and physical activity recommendations.