ReviewJournal of clinical epidemiology2015
Many multicenter trials had few events per center, requiring analysis via random-effects models or GEEs.
Review in Journal of clinical epidemiology, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 32 papers, 2 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
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
32 citing papers in PubMed, 2 syntheses or guidelines pooled it.
- Efficacy and safety of antithrombotic therapy for preventing and treating pediatric thromboembolic disease: a systematic review.Scientific reports · 2024Pooled it
- Direct oral anticoagulants versus standard anticoagulation in children treated for acute venous thromboembolism.Pediatric research · 2023Pooled it
- Trial
- Trial
- Center effect in intubation risk in critically ill immunocompromised patients with acute hypoxemic respiratory failure.Critical care (London, England) · 2019Trial
- Trial
- Prevention of haematoma progression by tranexamic acid in intracerebral haemorrhage patients with and without spot sign on admission scan: a statistical analysis plan of a pre-specified sub-study of the TICH-2 trial.BMC research notes · 2018Trial
- Trial
- Data Analysis Planning and Reporting for Confirmatory Multi-Lab Preclinical Trials: A Tutorial.Biometrical journal. Biometrische Zeitschrift · 2026Review
- Red Blood Cell Transfusion Characteristics and Morbidity or Mortality in Very-Low-Birth-Weight Infants.JAMA network open · 2026Observational
- The effect of human ratings reliability on machine learning model performance: a case study in infant pain assessment.Scientific reports · 2026Article
- Quantitative benefit-risk analysis for prophylactic vaccines in the context of FDAs benefit-risk framework.NPJ vaccines · 2026Review
- Article
- A framework for sequential monitoring of individual N-of-1 trials and combining results across a series of sequentially monitored N-of-1 trials.Clinical trials (London, England) · 2025Article
- Statistical methods in the analysis of multicentre HIV randomized controlled trials in the African region: a scoping review.BMC medical research methodology · 2025Article
- Proximal femoral fractures in patients with COVID-19 : Pneumonia and admission from a nursing home are the strongest predictors of mortality.Zeitschrift fur Gerontologie und Geriatrie · 2024Article
- Article
- Article
- MRSamePopTest: introducing a simple falsification test for the two-sample mendelian randomisation 'same population' assumption.BMC research notes · 2024Article
- Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
2 authors.
Funding
Abstract
objectivesAdjustment for center in multicenter trials is recommended when there are between-center differences or when randomization has been stratified by center. However, common methods of analysis (such as fixed-effects, Mantel-Haenszel, or stratified Cox models) often require a large number of patients or events per center to perform well. STUDY DESIGN AND
settingWe reviewed 206 multicenter randomized trials published in four general medical journals to assess the average number of patients and events per center and determine whether appropriate methods of analysis were used in trials with few patients or events per center.
resultsThe median number of events per center/treatment arm combination for trials using a binary or survival outcome was 3 (interquartile range, 1-10). Sixteen percent of trials had less than 1 event per center/treatment combination, 50% fewer than 3, and 63% fewer than 5. Of the trials which adjusted for center using a method of analysis which requires a large number of events per center, 6% had less than 1 event per center-treatment combination, 25% fewer than 3, and 50% fewer than 5. Methods of analysis that allow for few events per center, such as random-effects models or generalized estimating equations (GEEs), were rarely used.
conclusionMany multicenter trials contain few events per center. Adjustment for center using random-effects models or GEE with model-based (non-robust) standard errors may be beneficial in these scenarios.
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What OpenQuestion holds
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.