A flexible approach for causal inference with multiple treatments and clustered survival outcomes

Liangyuan Hu, Jiayi Ji, Ronald D. Ennis, Joseph W. Hogan

Research output: Contribution to journalArticlepeer-review


When drawing causal inferences about the effects of multiple treatments on clustered survival outcomes using observational data, we need to address implications of the multilevel data structure, multiple treatments, censoring, and unmeasured confounding for causal analyses. Few off-the-shelf causal inference tools are available to simultaneously tackle these issues. We develop a flexible random-intercept accelerated failure time model, in which we use Bayesian additive regression trees to capture arbitrarily complex relationships between censored survival times and pre-treatment covariates and use the random intercepts to capture cluster-specific main effects. We develop an efficient Markov chain Monte Carlo algorithm to draw posterior inferences about the population survival effects of multiple treatments and examine the variability in cluster-level effects. We further propose an interpretable sensitivity analysis approach to evaluate the sensitivity of drawn causal inferences about treatment effect to the potential magnitude of departure from the causal assumption of no unmeasured confounding. Expansive simulations empirically validate and demonstrate good practical operating characteristics of our proposed methods. Applying the proposed methods to a dataset on older high-risk localized prostate cancer patients drawn from the National Cancer Database, we evaluate the comparative effects of three treatment approaches on patient survival, and assess the ramifications of potential unmeasured confounding. The methods developed in this work are readily available in the (Formula presented.) package (Formula presented.).

Original languageAmerican English
Pages (from-to)4982-4999
Number of pages18
JournalStatistics in Medicine
Issue number25
StatePublished - Nov 10 2022

ASJC Scopus subject areas

  • Epidemiology
  • Statistics and Probability


  • Bayesian machine learning
  • multilevel survival data
  • observational studies
  • sensitivity analysis


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