When applying the RF algorithm for gene screening, with the criterion of Mean Decrease Gini >0.8 or 1 set, analyses were carried out for AF (Figure 5F) and CKD (Figure 5G) respectively, and the intersection of the two obtained through a Venn diagram yielded 7 characteristic genes: PPBP, CXCL1, CXCR2, LRRK2, RGS18, RSAD2, S100A8. The gene discussed is RGS18; the disease is chronic kidney disease.