Risk stratification for the development of chronic pulmonary aspergillosis in patients with Mycobacterium avium complex lung disease.

BACKGROUND: The number of patients with pulmonary nontuberculous mycobacterial disease complicated by chronic pulmonary aspergillosis (CPA) has been increasing. Additionally, CPA is reportedly associated with mortality in patients with Mycobacterium avium complex lung disease (MAC-LD). In the present study, we aimed to identify risk factors for developing CPA and stratify the risk for CPA development in patients with MAC-LD. METHODS: We retrospectively examined 361 patients newly diagnosed with MAC-LD. Risk factors for CPA development were examined using multivariate Cox proportional hazards regression analyses. A risk stratification system was established using the risk factors and receiver operating characteristic curve analyses. RESULTS: CPA developed in 20 (5.5%) of the 361 patients. Independent risk factors for CPA development included the presence of pulmonary emphysema, baseline steroid use, a serum albumin level <3.5 g/dL, and the presence of MAC-LD cavities. A 4-point scoring system was established to stratify patients into low-risk (0-1 point) and high-risk (2-4 points) groups. The 5-year incidence rates of CPA were 2.2% and 31% in the low- and high-risk groups, respectively (P < 0.001). CONCLUSIONS: We identified independent predictors of CPA development and established a simple risk stratification system for identifying patients with MAC-LD who were at a high risk of developing CPA.