Synthesis estimators for positivity violations with a continuous covariate

Fuente: arXiv
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Auteurs principaux: Zivich, Paul N, Edwards, Jessie K, Shook-Sa, Bonnie E, Lofgren, Eric T, Lessler, Justin, Cole, Stephen R
Format: Preprint
Publié: 2023
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author Zivich, Paul N
Edwards, Jessie K
Shook-Sa, Bonnie E
Lofgren, Eric T
Lessler, Justin
Cole, Stephen R
author_facet Zivich, Paul N
Edwards, Jessie K
Shook-Sa, Bonnie E
Lofgren, Eric T
Lessler, Justin
Cole, Stephen R
contents Studies intended to estimate the effect of a treatment, like randomized trials, may not be sampled from the desired target population. To correct for this discrepancy, estimates can be transported to the target population. Methods for transporting between populations are often premised on a positivity assumption, such that all relevant covariate patterns in one population are also present in the other. However, eligibility criteria, particularly in the case of trials, can result in violations of positivity when transporting to external populations. To address nonpositivity, a synthesis of statistical and mathematical models can be considered. This approach integrates multiple data sources (e.g. trials, observational, pharmacokinetic studies) to estimate treatment effects, leveraging mathematical models to handle positivity violations. This approach was previously demonstrated for positivity violations by a single binary covariate. Here, we extend the synthesis approach for positivity violations with a continuous covariate. For estimation, two novel augmented inverse probability weighting estimators are proposed. Both estimators are contrasted with other common approaches for addressing nonpositivity. Empirical performance is compared via Monte Carlo simulation. Finally, the competing approaches are illustrated with an example in the context of two-drug versus one-drug antiretroviral therapy on CD4 T cell counts among women with HIV.
format Preprint
id arxiv_https___arxiv_org_abs_2311_09388
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Synthesis estimators for positivity violations with a continuous covariate
Zivich, Paul N
Edwards, Jessie K
Shook-Sa, Bonnie E
Lofgren, Eric T
Lessler, Justin
Cole, Stephen R
Methodology
Studies intended to estimate the effect of a treatment, like randomized trials, may not be sampled from the desired target population. To correct for this discrepancy, estimates can be transported to the target population. Methods for transporting between populations are often premised on a positivity assumption, such that all relevant covariate patterns in one population are also present in the other. However, eligibility criteria, particularly in the case of trials, can result in violations of positivity when transporting to external populations. To address nonpositivity, a synthesis of statistical and mathematical models can be considered. This approach integrates multiple data sources (e.g. trials, observational, pharmacokinetic studies) to estimate treatment effects, leveraging mathematical models to handle positivity violations. This approach was previously demonstrated for positivity violations by a single binary covariate. Here, we extend the synthesis approach for positivity violations with a continuous covariate. For estimation, two novel augmented inverse probability weighting estimators are proposed. Both estimators are contrasted with other common approaches for addressing nonpositivity. Empirical performance is compared via Monte Carlo simulation. Finally, the competing approaches are illustrated with an example in the context of two-drug versus one-drug antiretroviral therapy on CD4 T cell counts among women with HIV.
title Synthesis estimators for positivity violations with a continuous covariate
topic Methodology
url https://arxiv.org/abs/2311.09388