Pfizer Inc., 235 East 42nd Street, New York, NY 10017, USA.
Stat Med. 2010 Oct 30;29(24):2486-500. doi: 10.1002/sim.4012.
Patient reported outcome and observer evaluative studies in clinical trials and post-hoc analyses often use instruments that measure responses on ordinal-rating or Likert scales. We propose a flexible distributional approach by modeling the change scores from the baseline to the end of the study using independent beta distributions. The two shape parameters of the fitted beta distributions are estimated by matching-moments. Covariates and the interaction terms are included in multivariate beta-regression analyses under generalized linear mixed models. These methods are illustrated on the treatment satisfaction data in an overactive bladder drug study with four treatment arms. Monte-Carlo simulations were conducted to compare the Type 1 errors and statistical powers using a beta likelihood ratio test of the proposed method against its fully nonparametric or parametric alternatives.
患者报告的结局和临床试验中的观察性评估研究以及事后分析通常使用在有序评分或李克特量表上测量反应的工具。我们通过使用独立的β分布来对从基线到研究结束的变化分数进行建模，提出了一种灵活的分布方法。拟合β分布的两个形状参数通过矩匹配来估计。协变量和交互项被纳入广义线性混合模型下的多元β回归分析中。这些方法在一个具有四个治疗组的过度活跃膀胱药物研究的治疗满意度数据上进行了说明。通过对拟议方法与完全非参数或参数替代方法的β似然比检验进行蒙特卡罗模拟，比较了该方法的Ⅰ类错误和统计功效。
