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

Abstract

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.