Fluid balance potentially mediated the association between GPR and TBI-induced AKI in part, with a mediating effect of 4.49 × 10<sup>-4</sup> (95% CI = 2.04 × 10<sup>-4</sup>-1.18 × 10<sup>-3</sup>, P < 0.001).<h4>Conclusions</h4>GPR is significantly associated with AKI risk in TBI patients, which may be mediated by FB. The gene discussed is ALDH18A1; the disease is acute kidney injury.