Trial reportJournal of clinical epidemiology2012
Covariate adjustment increased power in randomized controlled trials: an example in traumatic brain injury.
Trial report in Journal of clinical epidemiology, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 26 papers.
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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.
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Who cites it
26 citing papers in PubMed.
- Planning a method for covariate adjustment in individually randomised trials: a practical guide.Trials · 2022Trial
- Trial
- Trial
- Nurse practitioner care improves renal outcome in patients with CKD.Journal of the American Society of Nephrology : JASN · 2014Trial
- Trial
- A new method for dealing with collider bias in the PWP model for recurrent events in randomized controlled trials.BMC medical research methodology · 2025Article
- Research considerations for prospective studies of patients with coma and disorders of consciousness.Brain communications · 2024Review
- Phosphodiesterase-5 (PDE-5) Inhibitors as Therapy for Cerebrovascular Dysfunction in Chronic Traumatic Brain Injury.Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics · 2023Review
- Article
- On the 12th Day of Christmas, a Statistician Sent to Me . . .BMJ (Clinical research ed.) · 2022Article
- Prognostic Research in Traumatic Brain Injury: Markers, Modeling, and Methodological Principles.Journal of neurotrauma · 2021Review
- Overcoming underpowering: Trial simulations and a global rank end point to optimize clinical trials in children with heart disease.American heart journal · 2020Article
- Trauma-related drinking to cope: A novel approach to the self-medication model.Psychology of addictive behaviors : journal of the Society of Psychologists in Addictive Behaviors · 2020Article
- Efficient design and analysis of randomized controlled trials in rare neurological diseases: An example in Guillain-Barré syndrome.PloS one · 2019Article
- High-flow nasal cannula to prevent postextubation respiratory failure in high-risk non-hypercapnic patients: a randomized multicenter trial.Annals of intensive care · 2017Article
- A comparison of methods to adjust for continuous covariates in the analysis of randomised trials.BMC medical research methodology · 2016Article
- A re-randomisation design for clinical trials.BMC medical research methodology · 2015Article
- Covariate adjustment had similar benefits in small and large randomized controlled trials.Journal of clinical epidemiology · 2015Article
- Understanding clinical trials: emerging methodological issues.Intensive care medicine · 2014Article
- The risks and rewards of covariate adjustment in randomized trials: an assessment of 12 outcomes from 8 studies.Trials · 2014Article
Corrections and comments
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Authors and funding
9 authors.
Funding
Abstract
objectiveWe aimed to determine to what extent covariate adjustment could affect power in a randomized controlled trial (RCT) of a heterogeneous population with traumatic brain injury (TBI). STUDY DESIGN AND
settingWe analyzed 14-day mortality in 9,497 participants in the Corticosteroid Randomization After Significant Head Injury (CRASH) RCT of corticosteroid vs. placebo. Adjustment was made using logistic regression for baseline covariates of two validated risk models derived from external data (International Mission on Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury [IMPACT]) and from the CRASH data. The relative sample size (RESS) measure, defined as the ratio of the sample size required by an adjusted analysis to attain the same power as the unadjusted reference analysis, was used to assess the impact of adjustment.
resultsCorticosteroid was associated with higher mortality compared with placebo (odds ratio=1.25, 95% confidence interval=1.13-1.39). RESS of 0.79 and 0.73 were obtained by adjustment using the IMPACT and CRASH models, respectively, which, for example, implies an increase from 80% to 88% and 91% power, respectively.
conclusionModerate gains in power may be obtained using covariate adjustment from logistic regression in heterogeneous conditions such as TBI. Although analyses of RCTs might consider covariate adjustment to improve power, we caution against this approach in the planning of RCTs.
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