Table 3.

Urinary biomarker comparisons between the three AKI groups

Variables	No AKI	Stage 1 AKI	Stage 2–3 AKI	P-value
	N = 27	N = 30	N = 13
BASELINE
[TIMP-2]•[IGFBP7]	0.2 (0.1–0.9)	0.4 (0.2–1.5)	0.6 (0.1–2)	0.146
[TIMP-2]•[IGFBP7] >0.3, N (%)	11 (41)	17 (59)	8 (73)	0.157
[TIMP-2]•[IGFBP7] >0.7, N (%)	7 (26)	13 (45)	5 (45)	0.261
NGAL (ng/ml)	5 (1.8–9.1)	5.3 (2.1–13.6)	3.9 (1.9–11.6)	0.757
POSTOPERATIVE
[TIMP-2]•[IGFBP7]
2-hour postop	0.05 (0.04–0.13)	0.14 (0.05–0.59)	0.3 (0.06–2)	0.052*
2-hour postop >0.3, N (%)	5 (19)	11 (37)	6 (46)	0.143
2-hour postop >0.7, N (%)	4 (15)	6 (20)	5 (38)	0.238
12-hour postop	0.52 (0.18–1.63)	0.57 (0.08–0.96)	1.49 (0.28–3.25)	0.225
12-hour postop >0.3, N (%)	18 (67)	17 (57)	9 (69)	0.685
12-hour postop >0.7, N (%)	11 (41)	12 (40)	8 (62)	0.381
24-hour postop	0.19 (0.07–0.49)	0.27 (0.1–0.9)	1.71 (0.41–2.59)	0.027*
24-hour postop >0.3, N (%)	10 (37)	14 (47)	11 (85)	0.017
24-hour postop >0.7, N (%)	4 (15)	11 (37)	9 (69)	0.003
NGAL (ng/ml)
2-hour postop	2.5 (0.8–4.9)	4.9 (1.4–6.9)	2.2 (1.2–31.3)	0.697
12-hour postop	4.3 (3.5–9.8)	4.1 (2.1–7.2)	9 (3.7–18.9)	0.269
24-hour postop	6.2 (1.8–8.6)	3.4 (2–8.6)	10.3 (4.7–30.1)	0.019**

Data presented as count (%) or median (IQR)

^*Stage 2–3 AKI had higher 2-hr postop [TIMP-2]•[IGFBP7] than no AKI (P=0.033), and higher 24-hr postop [TIMP-2]•[IGFBP7] than no AKI (P=0.011)

^**Stage 2–3 AKI had higher 24-hr postop NGAL than both Stage 1 AKI (P=0.012) and no AKI (P=0.021)

AKI - acute kidney injury; [TIMP-2]•[IGFBP7] - tissue inhibitor of metalloproteinases 2, insulin-like growth factor-binding protein 7; NGAL - neutrophil gelatinase-associated lipocalin