Objective: To identify characteristics that differentiate lung disease due to non-tuberculous mycobacteria (NTM) from that due to pulmonary tuberculosis (PTB) in acid-fast bacilli (AFB) smear-positive patients with lung cavities.
Methods: From 2006 to 2012, 142 AFB smear- and culture-positive patients with lung cavities were identified at the Wonju Severance Christian Hospital, Wonju, Korea. Clinical and radiographic characteristics were compared between patients with NTM disease and PTB.
Results: Of 142 patients, 112 were diagnosed with PTB and 30 with NTM disease. Patients with NTM disease were older (62 vs. 49 years, P = 0.001), more likely to have had previous anti-tuberculosis treatment (18, 60.0% vs. 34, 30.6%; P = 0.001), more likely to have haemoptysis (9, 30.0% vs. 13, 11.9%; P = 0.022) and less likely to have consolidation on chest radiograph (20, 66.7% vs. 98, 87.5%; P = 0.007) than PTB patients. Multivariate analysis showed that age ≥65 years (OR 3.37, 95%CI 1.24-9.13, P = 0.010) and previous anti-tuberculosis treatment (OR 3.75, 95%CI 1.46-9.65, P = 0.006) were significantly associated with NTM disease.
Conclusions: Cavitary patients with positive AFB smears and NTM or PTB had considerable overlapping clinical characteristics, although patients aged ≥65 years or with a previous history of anti-tuberculosis treatment were more likely to have NTM.