Can we improve the statistical analysis of stroke trials? Statistical re-analysis of functional outcomes in stroke trials

Bath, Philip M.W. (2007) Can we improve the statistical analysis of stroke trials? Statistical re-analysis of functional outcomes in stroke trials. Stroke .

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Abstract

Background Most large acute stroke trials have been neutral. Functional outcome is usually analysed using a yes or no answer, e.g. death or dependency vs. independence. We assessed which statistical approaches are most efficient in analysing outcomes from stroke trials. Methods Individual patient data from acute, rehabilitation and stroke unit trials studying the effects of interventions which alter functional outcome were assessed. Outcomes included modified Rankin Scale, Barthel Index, and ‘3 questions’. Data were analysed using a variety of approaches which compare two treatment groups. The results for each statistical test for each trial were then compared. Results Data from 55 datasets were obtained (47 trials, 54,173 patients). The test results differed substantially so that approaches which use the ordered nature of functional outcome data (ordinal logistic regression, t-test, robust ranks test, bootstrapping the difference in mean rank) were more efficient statistically than those which collapse the data into 2 groups (chi square) (ANOVA p<0.001). The findings were consistent across different types and sizes of trial and for the different measures of functional outcome. Conclusions When analysing functional outcome from stroke trials, statistical tests which use the original ordered data are more efficient and more likely to yield reliable results. Suitable approaches included ordinal logistic regression, t-test, and robust ranks test.

Item Type:Article
Uncontrolled Keywords:stroke; randomised controlled trial; statistical analysis
Schools/Departments:University of Nottingham UK Campus > Faculty of Medicine and Health Sciences > School of Medicine > Division of Clinical Neuroscience
ID Code:947
Deposited By:Smith, Jane H
Deposited On:22 Aug 2008 10:25
Last Modified:14 Aug 2013 14:45

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