The ROC curve showed that the diagnostic performance of serum HE4 for DKD with 82.9 pM as the optimal cutoff value was good (AUC = 0.917, 95% CI: 0.872–0.961, P < 0.001, with a sensitivity and specificity of 92.1% and 76.9%, respectively) in T2DM patients (Figure 3). The gene discussed is WFDC2; the disease is type 2 diabetes mellitus.