Table 1.

Study population characteristics

		Adjusted Hospital Cost Tertile
	Overall (n=30,670; 27 hospitals)	Low (n=10,491; 9 hospitals)	Middle (n=11,419, 9 hospitals)	High (n=8760; 9 hospitals)	p-value
Patient Characteristics
Age at surgery, years*	0.6 (0.1–3.5)	0.6 (0.1–3.2)	0.6 (0.1–3.6)	0.6 (0.1–4.0)	<0.001
Neonates	6,687 (21.8%)	2,397 (22.8%)	2,435 (21.3%)	1,855 (21.2%)	<0.01
Weight at surgery, kg	6.7 (2.9–14.4)	6.6 (3.8–13.5)	6.6 (3.9–14.6)	6.8 (3.9–15.2)	<0.0001
Any previous CT surgery	9,264 (30.2%)	3,179 (30.3%)	3,375 (29.6%)	2,710 (30.9%)	0.44
Any non-cardiac/genetic anomaly	8,718 (28.4%)	3,079 (29.3%)	3,165 (27.7%)	2,474 (28.2%)	0.08
Any STS pre-op risk factor	7,585 (24.7%)	2,811 (26.8%)	2,733 (23.9%)	2,041 (23.3%)	<0.0001
STAT Category 4–5 (vs. 1–3)	7,566 (24.7%)	2,784 (26.5%)	2,785 (24.4%)	1,997 (22.8%)	<0.0001
Hospital Characteristics
Surgical Volume (cases/yr)	360 (286–420)	411 (351–580)	355 (333–406)	359 (249–383)	0.08

Data are presented as n (%) and median (interquartile range)

^*For age at surgery (years), 10% trimmed means as an additional measure of central tendency across groups are: low: 1.6, middle: 1.8, high: 2.0.