Figure 3.

Plasma IL-8 had the highest optimism-corrected area under the receiver operating curve (AUC) for the prediction of AKI progression. The adjusted model included the biomarker, cardiopulmonary bypass time, and preoperative eGFR percentile. The AUC with only the clinical variables is 0.67 (95% confidence interval [95% CI], 0.55 to 0.78). The optimism-corrected AUC was estimated using a bootstrap procedure with 1000 replicates. The model fitted using the bootstrap dataset was applied to the original dataset as well as the bootstrap dataset. The average difference in predictive abilities is the optimism. The average optimism in AUCs was subtracted from the apparent AUC to get the optimism-adjusted AUC. Cr, creatinine; KIM-1, kidney injury molecule 1; L-FABP, liver fatty acid binding protein; NGAL, neutrophil gelatinase–associated lipocalin.