🤖 AI Summary
Clinical prediction models (CPMs) often employ inconsistent missing-data handling strategies across their lifecycle—particularly overlooking deployment-stage constraints on missingness, leading to biased performance estimation. This study introduces the novel concept of “compatibility” to systematically evaluate consistency among missing-data methods across development, validation, and deployment phases. Using simulation studies, real-world thoracic surgical data, and a comprehensive case study, we compare mean imputation, single regression imputation, multiple imputation (MI), and pattern submodeling. Results indicate that when deployment prohibits missing values, MI should be used throughout all phases; when missingness is permitted at deployment, the same imputation method must be applied in both development and validation. Crucially, this work demonstrates how deployment constraints retroactively influence upstream modeling decisions. Our findings provide methodological guidance for robust CPM development and clinical translation, emphasizing phase-aligned missing-data strategies to ensure valid performance estimation and real-world applicability.
📝 Abstract
Missing data is a challenge when developing, validating and deploying clinical prediction models (CPMs). Traditionally, decisions concerning missing data handling during CPM development and validation havent accounted for whether missingness is allowed at deployment. We hypothesised that the missing data approach used during model development should optimise model performance upon deployment, whilst the approach used during model validation should yield unbiased predictive performance estimates upon deployment; we term this compatibility. We aimed to determine which combinations of missing data handling methods across the CPM life cycle are compatible. We considered scenarios where CPMs are intended to be deployed with missing data allowed or not, and we evaluated the impact of that choice on earlier modelling decisions. Through a simulation study and an empirical analysis of thoracic surgery data, we compared CPMs developed and validated using combinations of complete case analysis, mean imputation, single regression imputation, multiple imputation, and pattern sub-modelling. If planning to deploy a CPM without allowing missing data, then development and validation should use multiple imputation when required. Where missingness is allowed at deployment, the same imputation method must be used during development and validation. Commonly used combinations of missing data handling methods result in biased predictive performance estimates.