Prevalence of Drug-Resistant Mycobacterium tuberculosis in the Veterans Health Administration (VHA)

Background: In 2018, the CDC reported that isoniazid (INH)-resistant and multidrug-resistant Mycobacterium tuberculosis (MDR-TB, ie, resistant to at least INH and rifampin) represented 9.3% and 1.5% of TB cases, respectively, in the United States. Objective: We analyzed the prevalence of drug-resistant TB within the Veterans Health Administration (VHA) to determine factors associated with hospitalization. Method: Patients were identified using Council of State and Territorial Epidemiologists case definition for laboratory-confirmed TB by querying VHA data sources from January 1, 2010, to June 30, 2019. Susceptibility results were included for isolates from all body sites. Using a 2-proportion z test, we compared the following demographic factors for susceptible versus drug-resistant TB: age, gender, race/ethnicity, location of residence and birth. We also assessed the following clinical and hospitalization factors: pulmonary versus extrapulmonary disease, latent TB infection (LTBI) screening and treatment, length of stay (LOS), intensive care unit (ICU) stay, and death. Results: In total, 878 patients had lab-confirmed TB, and 812 (92%) had electronic drug-susceptibility results available. Of 812 patients, 49 (6%) showed anti-TB drug resistance (Fig. 1), which was less than that reported nationally by the CDC (Fig. 2). No patients had extensively drug-resistant TB. Only 18 of 49 patients (37%) with resistant TB had LTBI screening ≥3 months prior to diagnosis. Among 6 patients with LTBI, 3 (50%) received treatment. Patient state of residence was the only demographic factor associated with resistant TB. Arizona, Iowa, Massachusetts, Montana, Nevada, South Dakota, and Utah were significantly associated with drug-resistant TB cases ( P < .05); however, overall numbers of VHA TB cases in these states were low. Patients with resistant TB were more likely to have extrapulmonary TB (13 of 49, 26.5%) than patients with susceptible TB (111 of 763, 14.5%; P < .05) (Table 1). Mortality at 30 and 90 days for resistant ...