Pneumothorax in connective tissue disease-associated interstitial lung disease

Background Spontaneous pneumothorax is a complication that occurs in patients with connective tissue disease-associated interstitial lung disease (CTD-ILD); however, few studies on the clinical implications of pneumothorax for patients with CTD-ILD have been performed. Objectives This study aimed to investigate the incidence and prognostic significance of pneumothorax and the risk factors for its onset in patients with CTD-ILD. Methods This study included 140 consecutive patients with CTD-ILD. Clinical characteristics, laboratory findings, pulmonary function test results, and chest high-resolution computed tomography (HRCT) images were retrospectively evaluated. Results A total of 18 patients (12.9%) developed pneumothorax during their clinical course. The cumulative incidence of pneumothorax from the time of CTD-ILD diagnosis was 6.5%, 8.7%, and 11.3% at 1, 3, and 5 years, respectively. The 10-year survival rate was significantly lower in patients with pneumothorax (29.6%) than that in those without pneumothorax (81.3%). The development of pneumothorax was significantly associated with poor prognosis (HR 22.0; p < 0.010). Furthermore, a lower body mass index, greater extent of reticular abnormalities on HRCT, and administration of methylprednisolone pulse therapy were significantly associated with the development of pneumothorax. Conclusion Pneumothorax is a serious complication in the clinical course of patients with CTD-ILD and the onset of pneumothorax predicts a poor outcome.