GDF15 and chronic kidney disease: Supplementary Table 3 illustrates that heterogeneity persisted across all subgroups, with I2 statistics ranging from 53.1% to 96.5%. However, the dose-response relationship was not significant for patients with CKD (P = 0.120). Nonsignificant dose-response relationships also were observed in 3 subgroups with only 1 study, namely, African participants (P = 0.104), GDF-15 detection methods by LTIA (P = 0.754), and Milliplex map kits (P = 0.104).