Comparable characteristics of tuberculous and non-tuberculous mycobacterial cavitary lung diseases

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.

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.

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.

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.