Urinary biomarkers predict advanced acute kidney injury after cardiovascular surgery

Table 5 Discriminative improvement of combined biomarkers added to Liano’s score for prediction of advanced acute kidney injury

Model	AUC (95% CI)	p ^a	NRI^b (95% CI)	p ^c	IDI (95% CI)	p
Hour 3
Normalized (uHJV + uKIM-1)	0.898 (0.804 to 0.957)	NA
Liano’s + normalized (uHJV + uKIM-1)^d	0.931 (0.846 to 0.977)	0.330	1.149 (0.76 to 1.53)	< 0.001	0.383 (0.25 to 0.52)	< 0.001
Hour 6
Normalized (uHJV + uKIM-1 + uNGAL)	0.834 (0.728 to 0.912)	NA
Liano’s + normalized (uHJV + uKIM-1 + uNGAL)	0.867 (0.766 to 0.935)	0.499	1.030 (0.64 to 1.41)	< 0.001	0.343 (0.21 to 0.48)	< 0.001
Hour 12
Normalized (uHJV + uKIM-1 + uNGAL)	0.892 (0.769 to 0.963)	NA
Liano’s + normalized (uHJV + uKIM-1 + uNGAL)	0.923 (0.808 to 0.980)	0.344	0.831 (0.40 to 1.27)	< 0.001	0.353 (0.19 to 0.52)	< 0.001
Hour 24
Normalized (uKIM-1 + uHJV + uNGAL)	0.855 (0.720 to 0.941)	NA
Liano’s + normalized (uKIM-1 + uHJV + uNGAL)	0.882 (0.753 to 0.958)	0.288	1.162 (0.81 to 1.52)	< 0.001	0.387 (0.27 to 0.51)	< 0.001

AUC area under the receiver-operating characteristic curve, CI confidence interval, IDI integrated discrimination improvement, NRI net reclassification improvement, uHJV urinary hemojuvelin, uKIM-1 urinary kidney injury molecule-1, uNGAL urinary neutrophil gelatinase-associated lipocalin
^aCompared with normalized (uHJV + uKIM-1) at hour 3, normalized (uHJV + uKIM-1 + uNGAL) at hour 6, normalized (uHJV + uKIM-1 + uNGAL) at hour 12 and normalized (uKIM-1 + uHJV + uNGAL) at hour 24
^bThe ability of a risk marker to more accurately stratify individuals into higher or lower risk categories was investigated by NRI. We reclassified the patients who had subsequent advanced acute kidney injury (AKI) or who did not by using a priori risk categories of 0–12%, 12–30% and > 30% for the risk of advanced AKI
^cThe p value for increase in NRI in a model with urinary biomarkers combined with Liano’s score compared with urinary biomarkers alone
^dBest prediction model (greatest AUC), combined clinical model (Liano’s score) with biomarkers

ISSN: 1364-8535