Metformin use and post-exposure incident tuberculosis: a nationwide tuberculosis-contact cohort study in Taiwan

Patients with diabetes mellitus are susceptible to active tuberculosis (TB) and latent TB infection (LTBI) [1–3]. Close contact with patients with infectious TB is associated with an increased risk of having coprevalent TB or developing incident TB [4, 5]. However, information on the burden of incident TB in contacts with underlying diabetes is limited. Considering post-exposure TB in patients with diabetes, metformin has demonstrated anti-TB effects in preclinical studies and association with a low LTBI prevalence in a cross-sectional survey [6, 7]. Despite metformin's wide use and correlation with a lower TB risk in patients with type 2 diabetes (T2D) [8], the impact of metformin use during TB exposure on subsequent TB risk has not been thoroughly investigated. We aimed to obtain the rate of post-exposure incident TB, but not coprevalent TB, in T2D patients and evaluate whether TB risk can be modified by metformin use during the TB-exposure period. This TB contact cohort study showed that the risk of incident TB, not coprevalent TB, was highest in the diabetes group without metformin use during TB exposure, followed by the nondiabetes population, and was lowest in the diabetes group with metformin use https://bit.ly/3fpJyF0