*2.4. Univariate ROC Analysis for Predicting Renal Outcome*

To ensure statistical reliability, this study focused on 412 proteins quantified in more than 80% of urine samples [17], with missing values filled by local least squares imputation [18] (Table S4). To confirm that quantified urinary proteins could act as individual biomarkers, univariate receiver operating characteristic (ROC) analysis was performed in samples from the PPG and GPG, with the

resulting histogram of AUC values shown in Figure 5. The AUC values of MUC1, CTSA, ACP2, SERPING1, AMY2B, GM2A, and COL1A1 were 0.791, 0.786, 0.773, 0.771, 0.768, 0.759, and 0.753, respectively. ACP2, AMY2B, and COL1A1 were significantly more abundant, whereas MUC1, CTSA, SERPING1, and GM2A were significantly less abundant, in the GPG than in the PPG (*p*-value < 0.05 each). The 66 urinary proteins showed significance with AUCs of 0.5 (*p*-value < 0.05; Table S5). Clinically, urinary albumin is a common marker of DKD [2,5]. The AUCs of 18 proteins were higher than that of albumin (0.722), but the differences were not statistically significant based on likelihood ratio tests.

**Figure 5.** Histogram of area under the ROC curves (AUC) of 412 urinary proteins and ACR. Top seven proteins (MUC1, CTSA, ACP2, SERPING1, AMY2B, GM2A, and COL1A1) and ACR are represented with box plots.
