Increased risk of pulmonary tuberculosis in patients with previous non-tuberculous mycobacterial disease.

OBJECTIVE To investigate whether or not there is an increased risk of pulmonary tuberculosis (PTB) after non-tuberculous mycobacterial (NTM) disease. DESIGN A retrospective cohort study of 212 NTM patients and 4240 control cases. RESULTS Patients with previous NTM disease had a significantly higher incidence of PTB than controls (incidence rate ratio [IRR] 14.74, 95%CI 8.71-24.94, P < 0.0001). Cox's proportional hazards analysis yielded an adjusted hazards ratio (aHR) of 10.15 (95%CI 5.67-18.17, P < 0.05) for NTM-associated PTB. The majority of the PTB cases (17/23, 73.9%) were diagnosed within 6 months after the diagnosis of NTM disease. Older age (≥65 years, aHR 4.45, 95%CI 1.94-10.22, P < 0.05), male sex (aHR 1.75, 95%CI 1.01-3.13, P < 0.05), human immunodeficiency virus (HIV) infection (aHR 12.49, 95%CI 3.20-48.79, P < 0.05) and chronic obstructive pulmonary disease (aHR 4.46, 95%CI 2.19-9.10, P < 0.05) were independent risk factors for developing PTB after NTM disease. The cumulative incidence of PTB in patients with previous NTM disease was significantly higher than in controls (P < 0.0001, Kaplan-Meier analysis). However, there was no significant difference in the survival rates in the two cohorts. CONCLUSION Increased PTB prevalence after NTM disease was demonstrated. HIV infection was the greatest independent risk factor for subsequent development of PTB.