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Main Authors: Mou, Yunhan, Li, Fan, Esserman, Denise, Huang, Yuan
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2511.16773
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author Mou, Yunhan
Li, Fan
Esserman, Denise
Huang, Yuan
author_facet Mou, Yunhan
Li, Fan
Esserman, Denise
Huang, Yuan
contents Composite endpoints are widely used in cardiovascular clinical trials to improve statistical efficiency while preserving clinical relevance. The Win Ratio (WR) measure and more general frameworks of Win Statistics have emerged as increasingly popular alternatives to traditional time-to-first-event analyses. Although analytic sample size formulas for WR have been developed, they rely on design parameters that are often not straightforward to specify. Consequently, sample size determination in clinical trials with WR as the primary analysis is most often based on simulations, which can be computationally intensive. Moreover, these simulations commonly assume independence among component endpoints, an assumption that may not hold in practice and can lead to misleading power estimates. To address this challenge, we derive refined formulas to calculate the proportions of wins, losses, and ties for multiple prioritized time-to-event endpoints. These formulas rely on familiar design inputs and become directly applicable when integrated with existing sample size methods. We conduct a comprehensive assessment of how correlation among endpoints affects sample size requirements across varying design features. We further demonstrate the role of correlations through two case studies based on the landmark SPRINT and STICH clinical trials to generate further insights.
format Preprint
id arxiv_https___arxiv_org_abs_2511_16773
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Correlation Matters! Streamlining the Sample Size Procedure with Composite Time-to-event Endpoints
Mou, Yunhan
Li, Fan
Esserman, Denise
Huang, Yuan
Methodology
Composite endpoints are widely used in cardiovascular clinical trials to improve statistical efficiency while preserving clinical relevance. The Win Ratio (WR) measure and more general frameworks of Win Statistics have emerged as increasingly popular alternatives to traditional time-to-first-event analyses. Although analytic sample size formulas for WR have been developed, they rely on design parameters that are often not straightforward to specify. Consequently, sample size determination in clinical trials with WR as the primary analysis is most often based on simulations, which can be computationally intensive. Moreover, these simulations commonly assume independence among component endpoints, an assumption that may not hold in practice and can lead to misleading power estimates. To address this challenge, we derive refined formulas to calculate the proportions of wins, losses, and ties for multiple prioritized time-to-event endpoints. These formulas rely on familiar design inputs and become directly applicable when integrated with existing sample size methods. We conduct a comprehensive assessment of how correlation among endpoints affects sample size requirements across varying design features. We further demonstrate the role of correlations through two case studies based on the landmark SPRINT and STICH clinical trials to generate further insights.
title Correlation Matters! Streamlining the Sample Size Procedure with Composite Time-to-event Endpoints
topic Methodology
url https://arxiv.org/abs/2511.16773