Patterns of pulmonary function in smoking and nonsmoking patients with progressive systemic sclerosis.

Pulmonary involvement is a prominent feature in systemic sclerosis and a significant cause of morbidity and mortality. A restrictive ventilatory defect is typical and static lung volumes are usually reduced in patients with ILDs. The possibility of obstruction of small airways in progressive systemic sclerosis (SSc) has been suggested by widespread bronchiolectasis and peribronchial fibrosis noted at necropsy. A total of 46 patients with a diagnosis of SSc were retrospectively included in this study. Patients were classified according to their smoking status (never smokers, n = 34 and ex or current smokers, n = 12). Patients were also compared on the basis of the presence or not of an obstructive pattern on spirometry. The purpose of this study was to establish if SSc patients who are smokers have a different pattern of pulmonary function involvement. Our hypothesis was that smoking habit was not the only cause of air trapping and that the existence of small airway involvement secondary to SSc itself cannot be excluded.