Propensity Score-Based Borrowing-By-Parts Power Prior for Augmenting Control Arm in Clinical Trials: A Two-Stage Approach
摘要
It is often not feasible to conduct randomized clinical trials (RCTs) with a sufficiently large sample size in a pediatric study. A common strategy to improve feasibility is to borrow information from a comparable external adult study. However, adult trial subjects may not be directly comparable to pediatric patients due to differences in baseline characteristics, prognostic factors, comorbidities, and previous treatments. In this article, we propose a propensity score integrated borrowing-by-parts power prior to estimate the effect of treatment in a pediatric study using a Bayesian approach. Specifically, we first estimate the propensity scores to assess the comparability between the pediatric and adult study. We then form strata based on these propensity scores and apply a stratum-specific borrowing-by-parts power prior, allowing for greater flexibility in borrowing information from different components of the data. In addition, we introduce data-driven discounting parameters to determine the level of borrowing. An extensive simulation study is carried out to demonstrate the proposed approach. To illustrate the practical implementation of our approach, we apply it to a case study of systemic lupus erythematosus (SLE) disease.