Table 5.

Discrimination and reclassification of the combination of biomarkers and clinical model for AKI

	AUC-ROC (95% CI)	P value*	Category-free NRI (95% CI)	P value*	IDI (95% CI)	P value*
Clinical model†	0.840 (0.812 to 0.868)
Clinical model+sCysC	0.847 (0.819 to 0.874)	0.163	0.193 (0.052 to 0.405)	0.036	0.017 (0.009 to 0.026)	<0.001
Clinical model+NT-proBNP	0.855 (0.828 to 0.882)	0.013	0.462 (0.196 to 0.747)	0.001	0.028 (0.016 to 0.039)	<0.001
Clinical model+NT-proBNP+sCysC	0.859 (0.832 to 0.885)	0.006	0.531 (0.238 to 0.741)	<0.001	0.038 (0.025 to 0.051)	<0.001
Clinical model+NT-proBNP+sCysC vs clinical model+sCysC	–	0.015	0.328 (0.139 to 0.553)	0.002	0.021 (0.010 to 0.031)	<0.001
Clinical model+NT-proBNP+sCysC vs clinical model+NT-proBNP	–	0.223	0.167 (0.013 to 0.285)	0.017	0.011 (0.004 to 0.018)	0.003

Hosmer–Lemeshow goodness-of-fit test: for clinical model, χ² value=14.249(p=0.075); for clinical model+sCysC, χ² value=6.971 (p=0.54); for clinical model+NT-proBNP, χ² value=9.362 (p=0.313) or clinical model+NT-proBNP+sCysC, χ² value=4.245 (p=0.834).

*Biomarker+clinical model vs clinical model.

†The clinical model for detecting AKI is composed of chronic kidney disease, heart failure, sepsis, admission type, serum creatinine at admission and Acute Physiology and Chronic Health Evaluation Ⅱ score.

AKI, acute kidney injury; AUC-ROC, area under the receiver operating characteristic curve; IDI, incremental discrimination improvement; NRI, net reclassification index; NT-proBNP, N-terminal pro-B-type natriuretic peptide; sCysC, serum cystatin C.