TABLE 4.

Cardiac surgery-associated acute kidney injury by site

AKI Status	Overall (n = 799)	University of Michigan (n = 327)	Boston Children’s Hospital (n = 472)	P value*
CS-AKI, n (%)	289 (36)	216 (66)	73 (15)	<.001
Maximum CS-AKI stage
Stage I (mild)	80 (28)	50 (23)	30 (41)	.01
Stage II (moderate)	137 (47)	107 (50)	30 (41)
Stage III (severe)	72 (25)	59 (27)	13 (18)
First day of CS-AKI				<.001
Postoperative day 1	241 (83)	200 (93)	41 (56)
Postoperative day 2 or later	48 (17)	16 (7)	32 (44)
Duration of CS-AKI, days, median (IQR)	2 (1–3)	2 (1–3)	2 (1–3)	.61

Values are n (%) or median (interquartile range). CS-AKI, cardiac surgery-associated acute kidney injury; IQR, interquartile range.

^*P values were determined by Fisher’s exact tests or Wilcoxon rank sum tests.