Nonparametric Bayesian Adjustment of Unmeasured Confounders in Cox Proportional Hazards Models

Fuente: arXiv
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Main Authors: Orihara, Shunichiro, Sugasawa, Shonosuke, Ohigashi, Tomohiro, Nakagawa, Tomoyuki, Taguri, Masataka
Format: Preprint
Published: 2023
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author Orihara, Shunichiro
Sugasawa, Shonosuke
Ohigashi, Tomohiro
Nakagawa, Tomoyuki
Taguri, Masataka
author_facet Orihara, Shunichiro
Sugasawa, Shonosuke
Ohigashi, Tomohiro
Nakagawa, Tomoyuki
Taguri, Masataka
contents In observational studies, unmeasured confounders present a crucial challenge in accurately estimating desired causal effects. To calculate the hazard ratio (HR) in Cox proportional hazard models for time-to-event outcomes, two-stage residual inclusion and limited information maximum likelihood are typically employed. However, these methods are known to entail difficulty in terms of potential bias of HR estimates and parameter identification. This study introduces a novel nonparametric Bayesian method designed to estimate an unbiased HR, addressing concerns that previous research methods have had. Our proposed method consists of two phases: 1) detecting clusters based on the likelihood of the exposure and outcome variables, and 2) estimating the hazard ratio within each cluster. Although it is implicitly assumed that unmeasured confounders affect outcomes through cluster effects, our algorithm is well-suited for such data structures. The proposed Bayesian estimator has good performance compared with some competitors.
format Preprint
id arxiv_https___arxiv_org_abs_2312_02404
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Nonparametric Bayesian Adjustment of Unmeasured Confounders in Cox Proportional Hazards Models
Orihara, Shunichiro
Sugasawa, Shonosuke
Ohigashi, Tomohiro
Nakagawa, Tomoyuki
Taguri, Masataka
Methodology
In observational studies, unmeasured confounders present a crucial challenge in accurately estimating desired causal effects. To calculate the hazard ratio (HR) in Cox proportional hazard models for time-to-event outcomes, two-stage residual inclusion and limited information maximum likelihood are typically employed. However, these methods are known to entail difficulty in terms of potential bias of HR estimates and parameter identification. This study introduces a novel nonparametric Bayesian method designed to estimate an unbiased HR, addressing concerns that previous research methods have had. Our proposed method consists of two phases: 1) detecting clusters based on the likelihood of the exposure and outcome variables, and 2) estimating the hazard ratio within each cluster. Although it is implicitly assumed that unmeasured confounders affect outcomes through cluster effects, our algorithm is well-suited for such data structures. The proposed Bayesian estimator has good performance compared with some competitors.
title Nonparametric Bayesian Adjustment of Unmeasured Confounders in Cox Proportional Hazards Models
topic Methodology
url https://arxiv.org/abs/2312.02404