TABLE 1.

The Characteristics of the Entire Cohort and Univariate Analysis of the Associations of Hospital Volume and Patient Characteristics

Original Cohort (N: 1438)
	Total	Low Volume	%	Intermediate Volume	%	High Volume	%	P
Year of death								0.05
2000–2001	140	78	12.8	33	6.9	29	8.4
2002–2003	260	118	19.3	85	17.8	57	16.4
2004–2005	315	124	20.3	115	24.0	76	21.9
2006–2007	332	137	22.4	108	22.6	87	25.1
2008–2009	391	155	25.3	138	28.8	98	28.2
Age (y)								< 0.001
65–69	145	49	8.0	47	9.8	49	14.1
70–74	290	141	23.0	78	16.3	71	20.5
75–79	362	132	21.6	136	28.4	94	27.1
≥80	641	290	47.4	218	45.5	133	38.3
Sex								0.67
Male	960	402	65.7	327	68.3	231	66.6
Female	478	210	34.3	152	31.7	116	33.4
Marital status								0.97
Unmarried	181	75	12.3	63	13.2	43	12.4
Married	824	351	57.4	270	56.4	203	58.5
Other	433	186	30.4	146	30.5	101	29.1
Median household income								< 0.0001
Lowest quartile	332	179	31.0	103	22.1	50	15.1
2nd quartile	343	171	29.6	119	25.5	53	16.0
3rd quartile	344	129	22.4	113	24.2	102	30.8
Highest quartile	356	98	17.0	132	28.3	126	38.1
Unknown	63	35	5.7	12	2.5	16	4.6
Education <12 y								< 0.0001
Lowest quartile	349	112	19.3	121	26.5	116	34.9
2nd quartile	339	121	20.9	125	27.4	93	28.0
3rd quartile	349	163	28.1	114	25.0	72	21.7
Highest quartile	332	184	31.7	97	21.2	51	15.4
Unknown	69	32	5.2	22	4.6	15	4.3
Hospice care								0.01
0–3 d	1286	531	86.8	442	92.3	313	90.2
4 + d	152	81	13.2	37	7.7	34	9.8
Comorbidity scores								< 0.01
0	788	355	58.0	238	49.7	195	56.2
1	355	148	24.2	140	29.2	67	19.3
≥2	295	109	17.8	101	21.1	85	24.5
Geographic region								< 0.0001
West	636	294	48.0	200	41.8	142	40.9
Northeast	360	93	15.2	115	24.0	152	43.8
Midwest	152	73	11.9	51	10.7	28	8.1
South	290	152	24.8	113	23.6	25	7.2