TABLE 2.

Standardized mortality ratio analyses

	Stratum	Patients, n	Mortality		Standardized mortality ratio		P
			Observed, n (%)	Expected, n (%)*	Estimate	95% CI
Total	All	4883	311 (6.37)	594 (12.16)	0.52	0.424–0.568	0.001
Parsonnet score (categories)	0–6.9	951	4 (0.4)	20 (2.2)	0.20	0.069–0.583	0.001
	7.0–12.9	744	7 (0.9)	25 (3.4)	0.28	0.122–0.643	0.001
	13.0–16.9	831	17 (2.0)	39 (4.7)	0.44	0.249–0.764	0.001
	17.0–22.9	749	27 (3.6)	56 (7.5)	0.48	0.308–0.755	0.001
	23.0–32.9	829	53 (6.4)	117 (14.1)	0.45	0.332–0.618	0.001
	33.0–50.9	630	128 (20.3)	226 (35.9)	0.57	0.476–0.692	0.001
	≥51	149	75 (50.3)	110 (73.7)	0.68	0.566–0.821	0.001
Age (years)	<70	3032	111 (3.66)	273 (9.02)	0.41	0.304–0.485	0.001
	70–75	881	77 (8.74)	116 (13.2)	0.66	0.460–0.866	0.001
	76–79	535	55 (10.28)	99 (18.53)	0.55	0.349–0.730	0.001
	≥80	435	68 (15.63)	105 (24.13)	0.65	0.409–0.829	0.001
Surgical status	Elective	1785	54 (3.03)	169 (9.47)	0.32	0.215–0.413	0.001
	Emergent	426	92 (21.6)	115 (27.08)	0.80	0.537–1.033	0.080
	Urgent	2672	165 (6.18)	309 (11.58)	0.53	0.424–0.568	0.001

*Calculated as the average individual predicted mortality risk, as estimated by the Parsonnet score for each patient in the corresponding stratum