Evidence map›Paper›PMID 28222778›Full record

ArticleTrials2017

Sample size considerations for trials using cerebral white matter hyperintensity progression as an intermediate outcome at 1 year after mild stroke: results of a prospective cohort study.

Francesca M Chappell, Maria Del Carmen Valdés Hernández, Stephen D Makin, Kirsten Shuler, Eleni Sakka, Martin S Dennis, Paul A Armitage, Susana Muñoz Maniega, Joanna M Wardlaw

Abstract read
In one paragraph

Article in Trials, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
12citing 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

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

  1. Pooled it
  2. Article
  3. Article
  4. Review
  5. Review
  6. Article
  7. Article
  8. Article
  9. Article
  10. Review
  11. Article
  12. Advanced Neuroimaging of Cerebral Small Vessel Disease.Current treatment options in cardiovascular medicine · 2017
    Review
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

9 authors.

Francesca M ChappellNeuroimaging Sciences, Centre for Clinical Brain Sciences (CCBS) FU303e, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
Maria Del Carmen Valdés HernándezNeuroimaging Sciences, Centre for Clinical Brain Sciences (CCBS) FU303e, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
Stephen D MakinNeuroimaging Sciences, Centre for Clinical Brain Sciences (CCBS) FU303e, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
Kirsten ShulerNeuroimaging Sciences, Centre for Clinical Brain Sciences (CCBS) FU303e, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
Eleni SakkaNeuroimaging Sciences, Centre for Clinical Brain Sciences (CCBS) FU303e, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
Martin S DennisNeuroimaging Sciences, Centre for Clinical Brain Sciences (CCBS) FU303e, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
Paul A ArmitageAcademic Unit of Radiology, University of Sheffield, C Floor, Royal Hallamshire Hospital, Sheffield, S10 2JF, UK.
Susana Muñoz ManiegaNeuroimaging Sciences, Centre for Clinical Brain Sciences (CCBS) FU303e, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
Joanna M WardlawNeuroimaging Sciences, Centre for Clinical Brain Sciences (CCBS) FU303e, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK. joanna.wardlaw@ed.ac.uk.

Funding

Chief Scientist OfficeMedical Research Council MR/K026992/1Wellcome Trust
6 · The paper itself

Abstract

backgroundWhite matter hyperintensities (WMHs) are commonly seen on in brain imaging and are associated with stroke and cognitive decline. Therefore, they may provide a relevant intermediate outcome in clinical trials. WMH can be measured as a volume or visually on the Fazekas scale. We investigated predictors of WMH progression and design of efficient studies using WMH volume and Fazekas score as an intermediate outcome.

methodsWe prospectively recruited 264 patients with mild ischaemic stroke and measured WMH volume, Fazekas score, age and cardiovascular risk factors at baseline and 1 year. We modelled predictors of WMH burden at 1 year and used the results in sample size calculations for hypothetical randomised controlled trials with different analysis plans and lengths of follow-up.

resultsFollow-up WMH volume was predicted by baseline WMH: a 0.73-ml (95% CI 0.65-0.80, p < 0.0001) increase per 1-ml baseline volume increment, and a 2.93-ml increase (95% CI 1.76-4.10, p < 0.0001) per point on the Fazekas scale. Using a mean difference of 1 ml in WMH volume between treatment groups, 80% power and 5% alpha, adjusting for all predictors and 2-year follow-up produced the smallest sample size (n = 642). Other study designs produced samples sizes from 2054 to 21,270. Sample size calculations using Fazekas score as an outcome with the same power and alpha, as well as an OR corresponding to a 1-ml difference, were sensitive to assumptions and ranged from 2504 to 18,886.

conclusionsBaseline WMH volume and Fazekas score predicted follow-up WMH volume. Study size was smallest using volumes and longer-term follow-up, but this must be balanced against resources required to measure volumes versus Fazekas scores, bias due to dropout and scanner drift. Samples sizes based on Fazekas scores may be best estimated with simulation studies.

Indexed as

Magnetic Resonance ImagingSample SizeAgedAge FactorsChi-Square DistributionDisease ProgressionFemaleHumansLeukoencephalopathiesLinear ModelsLogistic ModelsMaleMiddle AgedOdds RatioPredictive Value of TestsPrognosisSample size calculationStudy designWhite matter hyperintensities

Identifiers

PMID28222778
PMCPMC5320698

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.