Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA.
Neuroepidemiology. 2011;37(2):73-82. doi: 10.1159/000330375. Epub 2011 Sep 1.
Ischemic stroke lesion volumes have proven difficult to analyze due to the extremely skewed shape of their underlying distribution. We introduce an extension of generalized linear models, beta regression, as a possible method of modeling extremely skewed distributions as evidenced in ischemic stroke lesion volumes.
The NINDS rt-PA clinical trials measured ischemic stroke lesion volume as a secondary trial outcome. Three-month lesion volumes from these trials were analyzed using beta regression. A multi-variable regression model associating explanatory variables with ischemic stroke lesion volumes was constructed using accepted model building strategies and compared with the previously published volumetric analysis.
Beta regression produced a similar model when compared to the previous analysis published by the study group. All previously identified variables of importance were detected in the model building process. The age by treatment interaction described in previous studies was also found in this analysis, confirming the strong effect age has on stroke outcomes. Further, a treatment effect was elicited in terms of odds ratios, yielding a previously unknown quantification of the effect of rt-PA on lesion volumes.
Beta regression proved adept in modeling ischemic stroke lesions and offered the interpretation of covariates in terms of odds ratios. Beta regression is seen as a legitimate alternative to analyze ischemic stroke volumes.
由于缺血性脑卒中病灶体积的基础分布呈极度偏态，因此其分析难度很大。我们引入广义线性模型的扩展——贝塔回归，作为分析缺血性脑卒中病灶体积这种极度偏态分布的一种可能方法。
NINDS rt-PA 临床试验将缺血性脑卒中病灶体积作为次要临床试验结果进行测量。本研究采用贝塔回归对这些试验中的三个月病灶体积进行分析。采用公认的模型构建策略，构建了一个与缺血性脑卒中病灶体积相关的解释变量的多变量回归模型，并与之前发表的容积分析进行了比较。
贝塔回归与研究小组之前发表的分析结果相似。在模型构建过程中，检测到了所有先前确定的重要变量。在本分析中还发现了之前研究中描述的年龄与治疗的相互作用，这证实了年龄对脑卒中结果的强烈影响。此外，还以优势比的形式得出了治疗效果，这对 rt-PA 对病灶体积的影响进行了以前未知的量化。
贝塔回归在对缺血性脑卒中病灶进行建模方面表现出色，并提供了协变量的优势比解释。贝塔回归被视为分析缺血性脑卒中体积的一种合理替代方法。
