Reduction in Expected Survival Associated With Nontuberculous Mycobacterial Pulmonary Disease

Nontuberculous mycobacteria (NTM) are opportunistically pathogenic bacteria that are found abundantly in the soil and water. Susceptible individuals exposed to NTM-containing aerosols from environmental sources may develop NTM pulmonary disease (NTM-PD). Reported survival after NTM-PD diagnosis varies widely among existing studies. Prior work has suggested that mortality among persons with NTM-PD is primarily driven by comorbidities rather than NTM-PD.

We retrospectively identified a cohort of patients in the Duke University Health System who were diagnosed with NTM-PD between 1996 and 2015. Hospitalizations and survival were compared among patients with NTM-PD with and without other comorbidities. Additionally, survival among patients with NTM-PD was compared with standardized mortality data for a similar cohort of the general population.

Patients with NTM-PD without other comorbidities had 0.65 hospitalizations/1000 patient-days compared with 1.37 hospitalizations/1000 patient-days for patients with other comorbidities. Compared with a cohort of the general population, expected survival decreased by approximately 4 years for a diagnosis of NTM-PD without comorbidities and 8.6 years for a diagnosis of NTM-PD with comorbidities. Mortality 5 years after diagnosis was 25.0% and 44.9% among NTM patients without and with comorbidities, respectively, compared with 5.7% in the general-population cohort.

NTM-PD was associated with significant morbidity that was worse in patients with comorbidities. Patients with NTM-PD, even without comorbidities, had worse survival than expected.