Evidence map›Paper›PMID 25648791›Full record

ReviewJournal of clinical epidemiology2015

A review of the use of covariates in cluster randomized trials uncovers marked discrepancies between guidance and practice.

Neil Wright, Noah Ivers, Sandra Eldridge, Monica Taljaard, Stephen Bremner

Abstract readReview
PubMed Full text at PMC Publisher
In one paragraph

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 29 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
29citing papers in PubMed, 1 pooled it
–field-weighted citation impact
1 · What the graph read from 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.

2 · The registry

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.

3 · Its place in the literature

Who cites it

29 citing papers in PubMed, 1 synthesis or guideline pooled it.

  1. Pooled it
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  4. Use of a personalised depression intervention in primary care to prevent anxiety: a secondary study of a cluster randomised trial.The British journal of general practice : the journal of the Royal College of General Practitioners · 2021
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  12. How should a cluster randomized trial be analyzed?Journal of epidemiology and population health · 2024
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Neil WrightCentre for Primary Care and Public Health, Blizard Institute, Queen Mary University of London, Yvonne Carter Building, 58 Turner Street, London, E1 2AB, United Kingdom. Electronic address: n.wright@qmul.ac.uk.
Noah IversFamily Practice Health Centre and Institute for Health Systems Solutions and Virtual Care, Women's College Hospital, 76 Grenville Street, Toronto, ON M5S1B2, Canada; Department of Family and Community Medicine, University of Toronto, 500 University Avenue, 5th Floor, Toronto, ON M5G1V7, Canada.
Sandra EldridgeCentre for Primary Care and Public Health, Blizard Institute, Queen Mary University of London, Yvonne Carter Building, 58 Turner Street, London, E1 2AB, United Kingdom.
Monica TaljaardClinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa Hospital, Civic Campus, 1053 Carling Avenue, Civic Box 693, Ottawa, Ontario K1Y 4E9, Canada; Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ontario, Canada.
Stephen BremnerCentre for Primary Care and Public Health, Blizard Institute, Queen Mary University of London, Yvonne Carter Building, 58 Turner Street, London, E1 2AB, United Kingdom.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectivesReviews of the handling of covariates in trials have explicitly excluded cluster randomized trials (CRTs). In this study, we review the use of covariates in randomization, the reporting of covariates, and adjusted analyses in CRTs. STUDY DESIGN AND

settingWe reviewed a random sample of 300 CRTs published between 2000 and 2008 across 150 English language journals.

resultsFifty-eight percent of trials used covariates in randomization. Only 69 (23%) included tables of cluster- and individual-level covariates. Fifty-eight percent reported significance tests of baseline balance. Of 207 trials that reported baseline measures of the primary outcome, 155 (75%) subsequently adjusted for these in analyses. Of 174 trials that used covariates in randomization, 30 (17%) included an analysis adjusting for all those covariates. Of 219 trial reports that included an adjusted analysis of the primary outcome, only 71 (32%) reported that covariates were chosen a priori.

conclusionThere are some marked discrepancies between practice and guidance on the use of covariates in the design, analysis, and reporting of CRTs. It is essential that researchers follow guidelines on the use and reporting of covariates in CRTs, promoting the validity of trial conclusions and quality of trial reports.

Indexed as

Cluster AnalysisGuideline AdherencePractice Guidelines as TopicRandom AllocationRandomized Controlled Trials as TopicResearch DesignResearch ReportAdjusted analysesBaseline imbalanceCluster randomized trialsCONSORT statementCovariatesRestricted randomization

Identifiers

PMID25648791
PMCPMC4425474

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

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.