2.4 Mendelian randomization analysis and sensitivity analysis
MR-Weighted mode, weighted median, inverse variance weighted (IVW), and
MR-Egger regression were adopted to
evaluate the significant causal association between gut microbiota and
the risk of MN. Because IVW combined the Wald ratio estimates of all
relevant instrumental variables, we selected IVW as the main analysis
method if the results of these four methods were inconsistent [6].
Cochran’s Q statistic was performed to estimate the potential
heterogeneity. IVW method was used to decrease the effect of
heterogeneity on the causal effect if there was remarkable heterogeneity
[16]. P > 0.05 was regarded as no heterogeneity.
Moreover, the MR-Egger regression test was employed to detect horizontal
pleiotropy, and the results with P < 0.05 were excluded
[17]. In addition, the MR-PRESSO test was also performed to find out
the outliers and adjust for the heterogeneity. Finally, we conducted the
leave-one-out analysis to identify and remove the potential outliers
that might influence the results.