An optimal learning method for developing personalized treatment regimes

TL;DR

This paper introduces a Bayesian, knowledge-gradient-based method for developing personalized treatment regimes, optimizing sequential medical decisions to improve outcomes and reduce costs, demonstrated on a knee replacement dataset.

Contribution

It proposes a novel Bayesian contextual bandit approach with a knowledge gradient policy for personalized treatment, incorporating prior information and sequential learning.

Findings

Improved success rates through careful physician selection.

Effective reduction of healthcare costs in real-world data.

Handling of sparse data with clustering and LASSO.

Abstract

A treatment regime is a function that maps individual patient information to a recommended treatment, hence explicitly incorporating the heterogeneity in need for treatment across individuals. Patient responses are dichotomous and can be predicted through an unknown relationship that depends on the patient information and the selected treatment. The goal is to find the treatments that lead to the best patient responses on average. Each experiment is expensive, forcing us to learn the most from each experiment. We adopt a Bayesian approach both to incorporate possible prior information and to update our treatment regime continuously as information accrues, with the potential to allow smaller yet more informative trials and for patients to receive better treatment. By formulating the problem as contextual bandits, we introduce a knowledge gradient policy to guide the treatment assignment by maximizing the expected value of information, for which an approximation method is used to overcome computational challenges. We provide a detailed study on how to make sequential medical decisions under uncertainty to reduce health care costs on a real world knee replacement dataset. We use clustering and LASSO to deal with the intrinsic sparsity in health datasets. We show experimentally that even though the problem is sparse, through careful selection of physicians (versus picking them at random), we can significantly improve the success rates.