Determinants of losses in the latent tuberculosis infection cascade of care in Brazil: a prospective multicenter cohort study

Abstract

Background: Factors associated with losses in the latent tuberculosis infection (LTBI) cascade of care in contacts of tuberculosis (TB) patients were investigated in a multicenter prospective cohort from highly endemic regions in Brazil. Methods: Close contacts of 1,187 culture-confirmed pulmonary TB patients were prospectively studied between 2015 and 2019, with follow-up between 6 and 24 months. Data on TB screening by clinical investigation, radiographic examination and interferon-gamma release assay (IGRA) were collected. Stepwise multivariable models were used to identify determinants of losses in the LTBI cascade. Results: Among 4,145 TB contacts initially identified, 1,901 were examined (54% loss). Within those individuals, 933 were people living with HIV, ≤5 years-old and/or had positive IGRA results, therefore having recommendation to start TB preventive treatment (TPT). Of those, 454 (23%) initiated treatment, and 247 (6% of all TB contacts) completed TPT. Multivariable regression analysis revealed that living with HIV, illiteracy, and black/pardo (brown) race were independently associated with losses in cascade. Conclusion: There were losses at all LTBI cascade stages, but particularly at the initial screening and examination steps. Close contacts who are socially vulnerable and living with HIV were at heightened risk of not completing the LTBI cascade of care in Brazil.