A simple, assumption-free, and clinically interpretable approach for analysis of modified Rankin outcomes.
A simple, assumption-free, and clinically interpretable approach for analysis of modified Rankin outcomes.
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DOI:
10.1161/strokeaha.111.632935
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发表时间:
2012-03
期刊:
影响因子:
8.3
通讯作者:
Hess DC
中科院分区:
文献类型:
--
作者:
Howard G;Waller JL;Voeks JH;Howard VJ;Jauch EC;Lees KR;Nichols FT;Rahlfs VW;Hess DC
There is debate regarding the approach for analysis of modified Rankin scores (mRS), the most common functional outcome scale used in acute stroke trials. We propose to use tests to assess treatment differences addressing the metric “If a patient is chosen at random from each treatment group and if they have different outcomes, what is the chance the patient who got the investigational treatment will have a better outcome than the patient receiving the standard treatment?” This approach has an associated statement of treatment efficacy easily understood by patients and clinicians, and leads to statistical testing of treatment differences by tests closely related to the Mann-Whitney U test (a.k.a. Wilcoxon Rank-Sum test) which can be tested precisely by permutation tests (a.k.a. randomization tests). We show that a permutation test is as powerful as other approaches assessing ordinal outcomes of the mRS scale, and provide data from several examples contrasting alternative approaches. While many approaches to analysis of mRS outcomes have generally similar statistical performances, this proposed approach: 1) captures information from the ordinal scale, 2) provides a powerful clinical interpretation understood by both patients and clinicians, 3) has power at least equivalent to the other ordinal approaches, 4) avoids assumptions in the parameterization, and 5) provides an interpretable parameter based on the same foundation as the calculation of the p-value.