Mycobacterium avium complex infection in non-cystic fibrosis bronchiectasis

Background and objective Reliable markers of disease progression or stability to assist in management decisions are lacking in patients with non-cystic fibrosis bronchiectasis and Mycobacterium avium complex (MAC) infection. Methods Data from 52 adults with non-cystic fibrosis bronchiectasis and coexisting MAC infection managed at our institution over a 5-year period were retrospectively analysed. High-resolution computed tomography (HRCT) scans were scored using a scoring system that focused on findings associated with MAC infection. Results Chronic pulmonary aspergillosis was independently associated with mortality (hazard ratio (HR)=8.916, 95% confidence interval (CI)=1.324-60.027), as were nodules with cavitation (HR=5.911, 95% CI=1.095-25.911) and emphysema (HR=1.027, 95% CI=1.002-1.053) on HRCT. Anti-MAC chemotherapy was more likely to lead to MAC culture conversion (67% vs 27%, P=0.005) but did not improve survival as compared with patients managed with observation. Longitudinally, patients who had improvements in HRCT scores were younger (60.2 +/- 9.19 years vs 69.83 +/- 12.43 years, P=0.043), while the presence of cavitation within nodules predicted a deterioration in HRCT scores (0.5 (0-3) vs 0 (0-1), P=0.033). No significant longitudinal differences were found in lung function in the cohort as a whole or within different groups. Conclusions Chronic pulmonary aspergillosis in patients with bronchiectasis and coexisting MAC infection is a strong predictor of mortality. Cavitation within nodules and emphysema on HRCT at presentation were independently associated with mortality.