Trial reportTrials2022
Planning a method for covariate adjustment in individually randomised trials: a practical guide.
Trial report in Trials, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 45 papers, 1 of them a synthesis that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
45 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Pooled it
- Trial
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- Timing of birth to improve outcomes in chronic or gestational hypertension: the WILL RCT.Health technology assessment (Winchester, England) · 2026Trial
- Impact of Aspirin on Timing of Birth in Pregnancies With Clinical Manifestations of Placental Dysfunction: Evidence From a Multicentre Randomised Clinical Trial.BJOG : an international journal of obstetrics and gynaecology · 2025Trial
- Treatment options to support the elimination of hepatitis C: an open-label, factorial, randomised controlled non-inferiority trial.Lancet (London, England) · 2025Trial
- Trial
- D3/Penta 21 clinical trial design: A randomised non-inferiority trial with nested drug licensing substudy to assess dolutegravir and lamivudine fixed dose formulations for the maintenance of virological suppression in children with HIV-1 infection, aged 2 to 15 years.Contemporary clinical trials · 2024Trial
- Trial
- An observer-blinded, cluster randomised trial of a typhoid conjugate vaccine in an urban South Indian cohort.Trials · 2023Trial
- Methods for Analysing Patient-Level Utility Data: Insights from the Literature Review and Recent NICE Technology Appraisals.PharmacoEconomics · 2026Review
- Article
- Protocol for a parallel-group superiority randomized controlled trial comparing Sage- a couple psychotherapy- to supportive individual psychotherapy for borderline personality disorder.BMC psychiatry · 2026Article
- Real-Time Stress Experiences and Physiological and Psychological Responses Among LGBTQ+ Young Adults: Findings from the Stress and Heart Pilot Study.Sensors (Basel, Switzerland) · 2026Article
- Article
- CRT-Estimands Framework: consensus based extension of the ICH E9(R1) addendum for cluster randomised trials.BMJ (Clinical research ed.) · 2026Article
- Estimating treatment effects in trials with outcome data truncated by death: A case study on aligning estimators with estimands.Clinical trials (London, England) · 2025Article
- How to manage missing covariates in randomized controlled trials: a comparison of strategies.BMC medical research methodology · 2025Article
- Current practice on covariate adjustment and stratified analysis -based on survey results by ASA oncology estimand working group conditional and marginal effect task force.BMC medical research methodology · 2025Article
- Covariate adjustment in cluster randomised trials: a practical guide.BMJ (Clinical research ed.) · 2025Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors.
Funding
Abstract
backgroundIt has long been advised to account for baseline covariates in the analysis of confirmatory randomised trials, with the main statistical justifications being that this increases power and, when a randomisation scheme balanced covariates, permits a valid estimate of experimental error. There are various methods available to account for covariates but it is not clear how to choose among them.
methodsTaking the perspective of writing a statistical analysis plan, we consider how to choose between the three most promising broad approaches: direct adjustment, standardisation and inverse-probability-of-treatment weighting.
resultsThe three approaches are similar in being asymptotically efficient, in losing efficiency with mis-specified covariate functions and in handling designed balance. If a marginal estimand is targeted (for example, a risk difference or survival difference), then direct adjustment should be avoided because it involves fitting non-standard models that are subject to convergence issues. Convergence is most likely with IPTW. Robust standard errors used by IPTW are anti-conservative at small sample sizes. All approaches can use similar methods to handle missing covariate data. With missing outcome data, each method has its own way to estimate a treatment effect in the all-randomised population. We illustrate some issues in a reanalysis of GetTested, a randomised trial designed to assess the effectiveness of an electonic sexually transmitted infection testing and results service.
conclusionsNo single approach is always best: the choice will depend on the trial context. We encourage trialists to consider all three methods more routinely.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.