Table 2.

Demographics of patients readmitted within 30-and 90-days of index hospitalization

		30-day		90-day
Variable of Interest		No. readmitted	% of readmitted	No. readmitted	% of readmitted
Anatomical Location of Pathology	Cervical	945	27.01	1195	28.24
	Thoracolumbar	2554	72.99	3036	71.76
Age	18–44	434	12.4	472	11.16
	45–59	934	26.69	1123	26.54
	60–74	1434	40.98	1732	40.94
	>=75	697	19.92	904	21.37
Gender	Male	1852	52.93	2235	52.82
	Female	1647	47.07	1996	47.18
Primary insurance	Medicare	1772	50.64	2252	53.23
	Medicaid	202	5.77	247	5.84
	Private insurance	1176	33.61	1317	31.13
	Self-pay	42	1.2	54	1.28
	No charge	11	0.31	12	0.28
	Other	289	8.26	340	8.04
Hospital bed size	Small	353	10.09	418	9.88
	Medium	773	22.09	944	22.31
	Large	2373	67.82	2869	67.81
Teaching status	Teaching	1983	56.67	2427	57.36
	Non-teaching	1516	43.33	1804	42.64
Disposition	Routine	1817	51.93	2102	49.68
	Short-term Hospital	39	1.11	49	1.16
	Transfer Other	919	26.26	1245	29.43
	Home Health Care	720	20.58	831	19.64
	Against Medical Advice	DS	DS	DS	DS
Volume	Above 90th percentile	1344	38.41	1621	38.31
	<= 90th percentile (652 / year)	2155	61.59	2610	61.69
Elixhauser comorbidity	Yes	2701	77.19	3323	78.54
	No	798	22.81	908	21.46
Medical complication	Yes	157	4.49	214	5.06
	No	3342	95.51	4017	94.94
Neurological complication	Yes	160	4.57	191	4.51
	No	3339	95.43	4040	95.49
Obesity	Yes	17	0.49	23	0.54
	No	3482	99.51	4208	99.46
Hypercoagulable state	Yes	DS	DS	DS	DS
	No	3493	99.83	4225	99.86
Index Length of stay	0–1days	475	13.58	577	13.64
	2days	511	14.6	618	14.61
	3–4days	1052	30.07	1245	29.43
	>=5days	1461	41.75	1791	42.33
Median household income for patient’s ZIP code, based on current year	0–25percentile	780	22.29	969	22.9
	26–50percentile	778	22.23	981	23.19
	51–75percentile	944	26.98	1115	26.35
	76–100 percentile	932	26.64	1090	25.76
Steroid use	Yes	59	1.69	89	2.1
	No	3440	98.31	4142	97.9
SIRS criteria	Yes	42	1.2	59	1.39
	No	3457	98.8	4172	98.61
History of chemotherapy	Yes	13	0.37	17	0.4
	No	3486	99.63	4214	99.6
Ventilator dependence	Yes	DS	DS	DS	DS
	No	3497	99.94	4229	99.5
Chronic lung disease	Yes	562	16.06	738	17.44
	No	2937	83.94	3493	82.56

^*DS = Data Suppressed according to HCUP/NRD regulations