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Exploring the effect of COVID-19 restrictions on the Social Functioning Scale in a clinical trial of Antipsychotic Reduction: using multiple imputation to target a hypothetical estimand

Louise Marston, Joanna Moncrieff, Stefan Priebe, Suzie Cro, Victoria R. Cornelius

Many trials are affected by unforeseen events after recruitment has commenced. The aim of this study is to explore a hypothetical strategy for dealing with an intercurrent event that occurred during trial follow-up; COVID-19 restrictions. Analysis was conducted using multiple imputation.

Journal of Clinical Epidemiology

Publication Date:

Mar 6, 2025

Application of causal forests to randomised controlled trial data to identify heterogeneous treatment effects: a case study

Eleanor Van Vogt, Anthony C. Gordon, Karla Diaz-Ordaz, Suzie Cro

This article conducted a secondary analysis of the VANISH RCT, which compared the early use of vasopressin with norepinephrine on renal failure-free survival for patients with septic shock at 28 days. This was done using classical (separate tests for interaction with Bonferroni correction), data-adaptive (hierarchical lasso regression), and non-parametric causal machine learning (causal forest) methods to analyse HTEs for the primary outcome of being alive at 28 days. The modal initial (root) splits of the causal forest were extracted, and the mean value was used as a threshold to partition the population into subgroups with different treatment effects.

BMC Medical Research Methodology

Publication Date:

Feb 22, 2025

Reference‐Based Multiple Imputation for Longitudinal Binary Data

Cro S, Quartagno M, White IR, Carpenter JR

This paper formulates and describes two algorithms for implementing reference-based multiple imputation for longitudinal binary outcome data using: (i) joint modeling with the multivariate normal distribution and an adaptive rounding algorithm and (ii) joint modeling with a latent multivariate normal model. A simulation study was performed to compare the properties of the two methods.

Statistics in Medicine

Publication Date:

Jan 24, 2025

All I want for Christmas…is a precisely defined research question

Cro S, Phillips R

Five years on from the publication of the ICH E9 (R1), this fun but informative article uses a trial conducted by Santa Clause to explain the importance of estimands to clearly specifying the precise research targeted in a trial.

Trials

Publication Date:

Dec 14, 2024

Past, present and future of Phase 3 vaccine trial design: rethinking statistics for the 21st century

Janani L, Phillips R, Van Vogt E, Liu X, Waddington C, Cro S

This paper provides an overview of the evolution of Phase 3 vaccine trial design and statistical analysis methods from traditional to more innovative contemporary methods.

Clinical and Experimental Immunology

Publication Date:

Nov 24, 2024

Public perspective on potential treatment intervention harm in clinical trials—terminology and communication

Rachel Phillips, Dongquan Bi, Beatriz Goulão, Marie Miller, Malak El-Askary, Oluyemi Fagbemi, Curie Freeborn, Maria Giammetta, Noura El Masri, Peter Flockhart, Manos Kumar, Mike Melvin, Dianne Murray, Anthony Myhill, Laila Saeid, Shanice Thomas, Graeme MacLennan and Victoria Cornelius

This work provides a starting point on preferred terminology by patients and the public to describe potential harmful intervention effects. Whilst researchers have tried to seek agreement, public partners endorsed use of different terms for different situations. We highlight some key areas for improvement in public facing materials that are necessary to avoid miscommunication and incorrect perception of harm.

Trials

Publication Date:

Aug 31, 2024

User engagement in clinical trials of digital mental health interventions: a systematic review

Jack Elkes, Suzie Cro, Rachel Batchelor, Siobhan O’Connor, Ly-Mee Yu, Lauren Bell, Victoria Harris, Jacqueline Sin & Victoria Cornelius

A systematic review to evaluate how user engagement data is reported and considered in the efficacy analysis of digital mental health interventions during randomised controlled trials.

BMC Medical Research Methodology

Publication Date:

Aug 24, 2024

Development and Evaluation of a Framework for Identifying and Addressing Spin for Harms in Systematic Reviews of Interventions

Qureshi R, Naaman K, Quan NG, Mayo-Wilson E, Page MJ, Cornelius V, Chou R, Boutron I, Golder S, Bero L, Doshi P, Vassar M, Reynders RM, Li T

The objectives of this research were threefold: first, to develop a framework for identifying spin associated with harms in systematic reviews of interventions; second, to apply the framework to a set of reviews, thereby pinpointing instances where spin may be present; and finally, to revise the spin examples, offering guidance on how spin can be rectified.

Annals of Internal Medicine

Publication Date:

Jul 16, 2024

Handling Partially Observed Trial Data After Treatment Withdrawal: Introducing Retrieved Dropout Reference-Base Centred Multiple Imputation

Cro S, Roger J, Carpenter J

This paper introduces a novel multiple imputation method for estimating a treatment policy estimand with missing data, referred to as retrieved dropout reference-base centred multiple imputation.

Pharmaceutical Statistics

Publication Date:

Jul 16, 2024

Optimal Significance Levels and Sample Sizes for Signal Detection Methods Based on Non-constant Hazards

Odile Sauzet, Julia Dyck, Victoria Cornelius

Statistical methods for signal detection of adverse drug reactions (ADRs) in electronic health records (EHRs) need information about optimal significance levels and sample sizes to achieve sufficient power. Sauzet and Cornelius proposed tests for signal detection based on the hazard functions of Weibull type distributions (WSP tests) which use the time-to-event information available in EHRs. Optimal significance levels and sample sizes for the application of the WPS tests are derived.

Drug safety

Publication Date:

Jul 9, 2024

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