Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, MN.
Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania, Philadelphia, PA.
J Clin Epidemiol. 2022 Feb;142:280-287. doi: 10.1016/j.jclinepi.2021.08.004. Epub 2021 Aug 9.
A recent paper by Doi et al. advocated completely replacing the relative risk (RR) with the odds ratio (OR) as the effect measure in clinical trials and meta-analyses with binary outcomes. Besides some practical advantages of RR over OR, Doi et al.'s key assumption that the OR is "portable" in the meta-analysis, that is, study-specific ORs are likely not correlated with baseline risks, was not well justified.
We summarized Spearman's rank correlation coefficient between study-specific ORs and baseline risks in 40,243 meta-analyses from the Cochrane Database of Systematic Reviews.
Study-specific ORs tend to be higher in studies with lower baseline risks of disease for most meta-analyses in Cochrane Database of Systematic Reviews. Using an actual meta-analysis example, we demonstrate that there is a strong negative correlation between OR (RR or RD) with the baseline risk and the conditional effects notably vary with baseline risks.
Replacing RR or RD with OR is currently unadvisable in clinical trials and meta-analyses. It is possible that no effect measure is "portable" in a meta-analysis. In addition to the overall (or marginal) effect, we suggest presenting the conditional effect based on the baseline risk using a bivariate generalized linear mixed model.
Doi 等人最近的一篇论文主张在二分类结局的临床试验和荟萃分析中，完全用优势比（OR）代替相对危险度（RR）作为效应量。除了 RR 比 OR 具有一些实际优势外，Doi 等人的主要假设，即 OR 在荟萃分析中是“可移植的”，即研究特异性 OR 不太可能与基线风险相关，这一假设并没有得到很好的证明。
我们总结了 Cochrane 系统评价数据库中 40243 项荟萃分析中研究特异性 OR 与基线风险之间的 Spearman 秩相关系数。
对于 Cochrane 系统评价数据库中的大多数荟萃分析，研究特异性 OR 往往在基线疾病风险较低的研究中更高。通过一个实际的荟萃分析例子，我们证明了 OR（RR 或 RD）与基线风险之间存在很强的负相关关系，条件效应随基线风险显著变化。
在临床试验和荟萃分析中，目前用 OR 替代 RR 或 RD 是不可取的。在荟萃分析中，可能没有一个效应量是“可移植的”。除了总体（或边缘）效应外，我们建议使用双变量广义线性混合模型根据基线风险呈现条件效应。
