效用加权改良 Rankin 量表作为卒中试验的主要结局指标：一项模拟研究。
Utility-Weighted Modified Rankin Scale as Primary Outcome in Stroke Trials: A Simulation Study.
机构信息
From the Department of Public Health (S.A.D., D.C.V., E.V., S.P., J.A.H., D.N., V.C., E.W.S., H.F.L.), Department of Neurology (E.V., B.R., V.C., J.S., D.W.J.D.), and Department of Radiology (B.R., V.C., A.v.d.L.), Erasmus MC University Medical Center, Rotterdam, the Netherlands; Division of Neurointervention, Texas Stroke Institute, Dallas (A.J.Y.); Department of Neurology, Elisabeth TweeSteden Hospital, Tilburg, the Netherlands (J.S.); Department of Radiology (C.B.L.M.M.) and Department of Neurology (Y.B.W.E.M.R.), Academic Medical Center, Amsterdam, the Netherlands; Department of Radiology, Maastricht University Medical Center, the Netherlands (W.H.v.Z.); Department of Neurology, Cardiovascular Research Institute, Maastricht University Medical Center, the Netherlands (R.J.v.O.); and Department of Medical Statistics and Bioinformatics, Leiden University Medical Center, the Netherlands (E.W.S.).
出版信息
Stroke. 2018 Apr;49(4):965-971. doi: 10.1161/STROKEAHA.117.020194. Epub 2018 Mar 13.
BACKGROUND AND PURPOSE
The utility-weighted modified Rankin Scale (UW-mRS) has been proposed as a new patient-centered primary outcome in stroke trials. We aimed to describe utility weights for the mRS health states and to evaluate the statistical efficiency of the UW-mRS to detect treatment effects in stroke intervention trials.
METHODS
We used data of the 500 patients enrolled in the MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands). Utility values were elicited from the EuroQol Group 5-Dimension Self-Report Questionnaire assessed at 90 days after inclusion, simultaneously with the mRS. Utility weights were determined by averaging the utilities of all patients within each mRS category. We performed simulations to evaluate statistical efficiency. The simulated treatment effect was an odds ratio of 1.65 in favor of the treatment arm, similar for all mRS cutoffs. This treatment effect was analyzed using 3 approaches: linear regression with the UW-mRS as outcome, binary logistic regression with a dichotomized mRS (0-1/2-6, 0-2/3-6, and 0-4/5-6), and proportional odds logistic regression with the ordinal mRS. The statistical power of the 3 approaches was expressed as the proportion of 10 000 simulations that resulted in a statistically significant treatment effect (≤0.05).
RESULTS
The mean utility values (SD) for mRS categories 0 to 6 were: 0.95 (0.08), 0.93 (0.13), 0.83 (0.21), 0.62 (0.27), 0.42 (0.28), 0.11 (0.28), and 0 (0), respectively, but varied substantially between individual patients within each category. The UW-mRS approach was more efficient than the dichotomous approach (power 85% versus 71%) but less efficient than the ordinal approach (power 85% versus 87%).
CONCLUSIONS
The UW-mRS as primary outcome does not capture individual variation in utility values and may reduce the statistical power of a randomized trial.
背景与目的
效用加权改良 Rankin 量表（UW-mRS）已被提议作为卒中试验中的一种新的以患者为中心的主要结局指标。我们旨在描述 mRS 健康状况的效用权重，并评估 UW-mRS 在卒中干预试验中检测治疗效果的统计效率。
方法
我们使用了纳入的 500 例患者的 MR CLEAN（荷兰多中心急性缺血性卒中血管内治疗随机临床试验）数据。效用值是通过在纳入后 90 天时使用欧洲五维健康量表自我报告问卷（EuroQol Group 5-Dimension Self-Report Questionnaire）评估得出的，同时评估 mRS。效用权重是通过平均每个 mRS 类别内所有患者的效用来确定的。我们进行了模拟以评估统计效率。模拟的治疗效果是治疗组的优势比为 1.65，所有 mRS 截断值相似。使用 3 种方法分析该治疗效果：以 UW-mRS 为结局的线性回归、以二分类 mRS（0-1/2-6、0-2/3-6 和 0-4/5-6）为结局的二项逻辑回归和以有序 mRS 为结局的比例优势逻辑回归。3 种方法的统计效能表示为 10000 次模拟中导致有统计学意义的治疗效果（≤0.05）的比例。
结果
mRS 0-6 各分类的平均效用值（标准差）分别为：0.95（0.08）、0.93（0.13）、0.83（0.21）、0.62（0.27）、0.42（0.28）、0.11（0.28）和 0（0），但每个分类内的个体患者之间差异很大。UW-mRS 方法比二分类方法更有效（效能 85%比 71%），但比有序方法效率更低（效能 85%比 87%）。
结论
作为主要结局的 UW-mRS 并不能捕捉到效用值的个体差异，可能会降低随机试验的统计效能。
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