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Activity Number:
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177
- Statistical Modeling of Lifetime Data: LiDS Section Student Award Session
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Type:
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Contributed
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Date/Time:
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Tuesday, August 4, 2020 : 10:00 AM to 2:00 PM
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Sponsor:
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Lifetime Data Science Section
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Abstract #311049
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Title:
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Counterfactual Mediation Analysis with Multistate Models for Surrogate and Clinical Time-to-Event Outcomes
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Author(s):
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Isabelle Weir* and Jennifer Rider and Ludovic Trinquart
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Companies:
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Harvard T. H. Chan School of Public Health and Boston University and Boston University School of Public Health
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Keywords:
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Surrogate outcome;
mediation;
censored mediator;
restricted mean;
multistate model
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Abstract:
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We introduce a counterfactual-based mediation analysis for surrogacy evaluation with time-to-event surrogate and clinical outcomes. Our approach accommodates censoring and competing risks. We use a multistate model for risk prediction to account for both transitions towards the clinical outcome and transitions through the surrogate outcome. We use the counterfactual framework to define the natural direct and indirect effects with a causal interpretation. Based on these measures, we define the proportion of the treatment effect on the clinical outcome mediated by the surrogate outcome. We estimate the proportion for both the cumulative risk and restricted mean time lost. We illustrate our approach using 18-year follow-up data from the SPCG-4 randomized trial of radical prostatectomy for prostate cancer. We assess time to metastasis as a surrogate outcome for prostate cancer-specific mortality.
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Authors who are presenting talks have a * after their name.
