C28-11 Prevalence of Post-tuberculosis Bronchiectasis and Association With Nontuberculous Mycobacterial Disease in the U.S. Bronchiectasis and Nontuberculous Mycobacteria Research Registry

Abstract Rationale Post-tuberculosis lung disease (PTLD) is a significant yet underdiagnosed cause of bronchiectasis. Multiple international studies have described characteristics of post-tuberculosis (TB) bronchiectasis, some revealing a higher incidence of NTM infection. Data from the United States is sparse due to a lower incidence of TB. Using the U.S. Bronchiectasis and NTM Research Registry (BRR), we examined whether a prior history of TB is associated with NTM growth. Methods Adult bronchiectasis patients enrolled in the BRR were included. Missing demographic data, unknown smoking history, missing answer to history of TB, and no baseline mycobacterial culture results were exclusionary, where baseline is defined as the 2-year period prior to enrollment. Patients were dichotomized by having a history of TB. Univariate analysis of demographics and clinical variables were summarized descriptively. Propensity scores were estimated using a logistic regression model including age, sex, race/ethnicity, BMI, smoking history, and cough history, followed by 1:3 nearest-neighbor matching without replacement. We fit a logistic regression model to assess the association between prior TB and NTM culture prevalence, adjusting for covariates with residual imbalance (standardized mean difference SMD ≥0.1) after matching. Results 4432 patients were included (median age 69.0 IQR: 60.0-76.0 years). Among these, 2.4% (n = 108) reported history of TB. Compared to those without TB, these patients were more often male (26.9% vs. 19.5%, SMD=0.20), had more pulmonary-related hospitalizations (27.1% vs. 20.2%, SMD=0.12), and had a higher median number of AFB cultures collected (3 IQR:2-3 vs. 2 IQR: 1-3, SMD=0.30). Patients with no history of TB had more exacerbations at baseline (58.8% vs. 50.9%) and dyspnea (45.3% vs. 38.0%). In univariable analyses, NTM culture positivity was more common among patients with history of TB (60.2% vs. 54.9%). After propensity score matching, residual imbalance remained for exacerbations, hospitalizations, dyspnea, fatigue, cough, and AFB cultures (SMDs=0.10-0.23). When these remaining differences were adjusted for in multivariable analysis, there was no significant link between prior TB and the presence of NTM (OR = 1.05, 95% CI: 0.63-1.76). Conclusions Post-TB bronchiectasis is underdiagnosed in the US, leading to limited referrals to specialty care and limited enrollment in research registries. Contrary to global trends, our analysis did not show an association between history of pulmonary TB and growth of NTM. Efforts to recruit broader populations of patients with bronchiectasis into the BRR are ongoing, and a detailed history of exposure may result in an improved analysis in a country with high rates of NTM infection. This abstract is funded by: none