Epidemiology of nontuberculous mycobacterial infections in the U.S. Veterans Health Administration.

OBJECTIVE:We identified patients with non-tuberculous mycobacterial (NTM) disease in the US Veterans Health Administration (VHA), examined the distribution of diseases by NTM species, and explored the association between NTM disease and the frequency of clinic visits and mortality. METHODS:We combined mycobacterial isolate (from natural language processing) with ICD-9-CM diagnoses from VHA data between 2008 and 2012 and then applied modified ATS/IDSA guidelines for NTM diagnosis. We performed validation against a reference standard of chart review. Incidence rates were calculated. Two nested case-control studies (matched by age and location) were used to measure the association between NTM disease and each of 1) the frequency of outpatient clinic visits and 2) mortality, both adjusted by chronic obstructive pulmonary disease (COPD), other structural lung diseases, and immunomodulatory factors. RESULTS:NTM cases were identified with a sensitivity of 94%, a specificity of >99%. The incidence of NTM was 12.6/100k patient-years. COPD was present in 68% of pulmonary NTM. NTM incidence was highest in the southeastern US. Extra-pulmonary NTM rates increased during the study period. The incidence rate ratio of clinic visits in the first year after diagnosis was 1.3 [95%CI 1.34-1.35]. NTM patients had a hazard ratio of mortality of 1.4 [95%CI 1.1-1.9] in the 6 months after NTM identification compared to controls and 1.99 [95%CI 1.8-2.3] thereafter. CONCLUSIONS:In VHA, pulmonary NTM disease is commonly associated with COPD, with the highest rates in the southeastern US. After adjustment, NTM patients had more clinic visits and greater mortality compared to matched patients

NTM patient demographics and major co-morbidities, along with age- and setting-matched controls.

<p>NTM patient demographics and major co-morbidities, along with age- and setting-matched controls.</p

Kaplan-Meier curves of survival after pulmonary and extra-pulmonary NTM diagnosis compared to age- and clinical-setting matched controls.

<p>Kaplan-Meier curves of survival after pulmonary and extra-pulmonary NTM diagnosis compared to age- and clinical-setting matched controls.</p

Incidence rates of NTM cases per 100,000 patient-years receiving care in VA over time.

<p>Incidence rates of NTM cases per 100,000 patient-years receiving care in VA over time.</p

Incident rates of NTM cases per 100,000 patient-years by region and by microbiologically-identified organism from 2009 through 2012.

<p>Reprinted from Esri^® ArcGIS Online^® under a CC BY license, with permission from Environmental Systems Research Institute, Inc., original copyright 2017.</p

Mycobacterial categories found in microbiology and laboratory data in VHA.

<p>Mycobacterial categories found in microbiology and laboratory data in VHA.</p

United States Veterans Health System regions grouped by first three digits of zip code.

<p>Incidence rates area denominated by 100,000 patient-years. Moran’s I measures the spatial correlation of a region with adjacent regions; positive correlations are >1, while negative correlations are <1. Reprinted from Esri^® ArcGIS Online^® under a CC BY license, with permission from Environmental Systems Research Institute, Inc., original copyright 2017.</p

Multivariable models of outpatient clinic visit rates and mortality.

<p>Mortality is split into early and late periods in piecewise models.</p