Schwarzer Guido, Rücker Gerta, Semaca Cristina
Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center - University of Freiburg, Freiburg, Germany.
Master's Degree Program, Medical Biometry/Biostatistics, University of Heidelberg, Heidelberg, Germany.
Res Synth Methods. 2024 Jul;15(4):603-615. doi: 10.1002/jrsm.1714. Epub 2024 Mar 11.
The LFK index has been promoted as an improved method to detect bias in meta-analysis. Putatively, its performance does not depend on the number of studies in the meta-analysis. We conducted a simulation study, comparing the LFK index test to three standard tests for funnel plot asymmetry in settings with smaller or larger group sample sizes. In general, false positive rates of the LFK index test markedly depended on the number and size of studies as well as the between-study heterogeneity with values between 0% and almost 30%. Egger's test adhered well to the pre-specified significance level of 5% under homogeneity, but was too liberal (smaller groups) or conservative (larger groups) under heterogeneity. The rank test was too conservative for most simulation scenarios. The Thompson-Sharp test was too conservative under homogeneity, but adhered well to the significance level in case of heterogeneity. The true positive rate of the LFK index test was only larger compared with classic tests if the false positive rate was inflated. The power of classic tests was similar or larger than the LFK index test if the false positive rate of the LFK index test was used as significance level for the classic tests. Under ideal conditions, the false positive rate of the LFK index test markedly and unpredictably depends on the number and sample size of studies as well as the extent of between-study heterogeneity. The LFK index test in its current implementation should not be used to assess funnel plot asymmetry in meta-analysis.
LFK指数已被推崇为检测荟萃分析中偏倚的一种改进方法。据推测，其性能不取决于荟萃分析中的研究数量。我们进行了一项模拟研究，在样本量较小或较大的情况下，将LFK指数检验与三种漏斗图不对称性的标准检验进行比较。总体而言，LFK指数检验的假阳性率显著取决于研究的数量和规模以及研究间的异质性，其值在0%至近30%之间。在同质性条件下，Egger检验很好地符合预先设定的5%显著性水平，但在异质性条件下过于宽松（样本量较小的组）或保守（样本量较大的组）。秩检验在大多数模拟场景中过于保守。Thompson-Sharp检验在同质性条件下过于保守，但在异质性情况下很好地符合显著性水平。只有当假阳性率被夸大时，LFK指数检验的真阳性率才比经典检验大。如果将LFK指数检验的假阳性率用作经典检验的显著性水平，经典检验的功效与LFK指数检验相似或更大。在理想条件下，LFK指数检验的假阳性率显著且不可预测地取决于研究的数量和样本量以及研究间异质性的程度。目前实施的LFK指数检验不应被用于评估荟萃分析中的漏斗图不对称性。
