Risk Factors for Clinical Progression in Patients with Pulmonary Mycobacterium Avium Complex Disease Without Culture-Positive Sputum: a Single-Center, Retrospective Study.

Limited data are available on the progression of pulmonary Mycobacterium avium complex (MAC) disease without culture-positive sputum. The aim of this study was to identify the risk factors associated with clinical progression of pulmonary MAC disease diagnosed by bronchoscopy. A single-center, retrospective, observational study was conducted. Pulmonary MAC patients diagnosed by bronchoscopy without culture-positive sputum from January 1, 2013, to December 31, 2017 were analyzed. Clinical progression after diagnosis was defined as having culture-positive sputum at least once or initiation of guideline-based therapy. Then, clinical characteristics were compared between clinically progressed patients and stable patients. Ninety-three pulmonary MAC patients diagnosed by bronchoscopy were included in the analysis. During the 4-year period after diagnosis, 38 patients (40.9