Evaluating the impact of outcome delay on the efficiency of two-arm group-sequential trials

Fuente: arXiv
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Hauptverfasser: Mukherjee, Aritra, Grayling, Michael J., Wason, James M. S.
Format: Preprint
Veröffentlicht: 2023
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author Mukherjee, Aritra
Grayling, Michael J.
Wason, James M. S.
author_facet Mukherjee, Aritra
Grayling, Michael J.
Wason, James M. S.
contents Adaptive designs(AD) are a broad class of trial designs that allow preplanned modifications based on patient data providing improved efficiency and flexibility. However, a delay in observing the primary outcome variable can harm this added efficiency. In this paper, we aim to ascertain the size of such outcome delay that results in the realised efficiency gains of ADs becoming negligible compared to classical fixed sample RCTs. We measure the impact of delay by developing formulae for the no. of overruns in 2 arm GSDs with normal data, assuming different recruitment models. The efficiency of a GSD is usually measured in terms of the expected sample size (ESS), with GSDs generally reducing the ESS compared to a standard RCT. Our formulae measures the efficiency gain from a GSD in terms of ESS reduction that is lost due to delay. We assess whether careful choice of design (e.g., altering the spacing of the IAs) can help recover the benefits of GSDs in presence of delay. We also analyse the efficiency of GSDs with respect to time to complete the trial. Comparing the expected efficiency gains, with and without consideration of delay, it is evident GSDs suffer considerable losses due to delay. Even a small delay can have a significant impact on the trial's efficiency. In contrast, even in the presence of substantial delay, a GSD will have a smaller expected time to trial completion in comparison to a simple RCT. Greater efficiency is lost with increase in the no. of stages. The timing of IAs also can impact the efficiency of a GSDs with delay. Particularly, for unequally spaced IAs, conducting IAs too early in the trial can be harmful for the design with delay.
format Preprint
id arxiv_https___arxiv_org_abs_2306_04430
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Evaluating the impact of outcome delay on the efficiency of two-arm group-sequential trials
Mukherjee, Aritra
Grayling, Michael J.
Wason, James M. S.
Methodology
Applications
Other Statistics
Adaptive designs(AD) are a broad class of trial designs that allow preplanned modifications based on patient data providing improved efficiency and flexibility. However, a delay in observing the primary outcome variable can harm this added efficiency. In this paper, we aim to ascertain the size of such outcome delay that results in the realised efficiency gains of ADs becoming negligible compared to classical fixed sample RCTs. We measure the impact of delay by developing formulae for the no. of overruns in 2 arm GSDs with normal data, assuming different recruitment models. The efficiency of a GSD is usually measured in terms of the expected sample size (ESS), with GSDs generally reducing the ESS compared to a standard RCT. Our formulae measures the efficiency gain from a GSD in terms of ESS reduction that is lost due to delay. We assess whether careful choice of design (e.g., altering the spacing of the IAs) can help recover the benefits of GSDs in presence of delay. We also analyse the efficiency of GSDs with respect to time to complete the trial. Comparing the expected efficiency gains, with and without consideration of delay, it is evident GSDs suffer considerable losses due to delay. Even a small delay can have a significant impact on the trial's efficiency. In contrast, even in the presence of substantial delay, a GSD will have a smaller expected time to trial completion in comparison to a simple RCT. Greater efficiency is lost with increase in the no. of stages. The timing of IAs also can impact the efficiency of a GSDs with delay. Particularly, for unequally spaced IAs, conducting IAs too early in the trial can be harmful for the design with delay.
title Evaluating the impact of outcome delay on the efficiency of two-arm group-sequential trials
topic Methodology
Applications
Other Statistics
url https://arxiv.org/abs/2306.04430