The impact of directly observed therapy on the efficacy of Tuberculosis treatment: A Bayesian multilevel approach

We propose and discuss a Bayesian procedure to estimate the average treatment effect (ATE) for multilevel observations in the presence of confounding. We focus on situations where the confounders may be latent (e.g., spatial latent effects). This work is motivated by an interest in determining the causal impact of directly observed therapy (DOT) on the successful treatment of Tuberculosis (TB); the available data correspond to individual-level information observed across different cities in a state in Brazil. We focus on propensity score regression and covariate adjustment to balance the treatment (DOT) allocation. We discuss the need to include latent local-level random effects in the propensity score model to reduce bias in the estimation of the ATE. A simulation study suggests that accounting for the multilevel nature of the data with latent structures in both the outcome and propensity score models has the potential to reduce bias in the estimation of causal effects.