Table 1.

Baseline Patient Characteristics Including Medical Comorbidities at the Time of Surgery, Preoperative Condition, and Operative Variables.

	No Chronic Steroids		Chronic Steroids
	n	%	n	%	P
Age
≥65 years	9167	41.6	444	52.3	<.0001
Sex
Male	9997	45.3	309	36.4	<.0001
Female	12 057	54.7	540	63.6
Race
White	18 652	84.7	724	85.4	<.9134
Black	1558	7.1	60	7.1
Hispanic	190	0.9	7	0.8
Other	1655	7.4	57	6.7
Medical comorbidities
Diabetes	3824	17.3	176	20.7	<.0107
Smoking	4756	21.6	127	15.0	<.0001
Pulmonarya	2148	9.7	147	17.3	<.0001
Cardiacb	12 531	56.8	584	68.8	<.0001
Renalc	38	0.2	3	0.4	.2207
Bleeding disorder	326	1.5	28	3.3	<.0001
Underweight	202	0.9	8	0.9	.937
Obese class I, II, III	10 728	48.8	398	47.1	.3419
Obese class II, III	4837	21.9	191	22.5	.6966
Obese class III	1817	8.2	62	7.3	.3294
Preoperative condition
ASA class ≥3	10 407	47.3	599	70.6	<.0001
Dyspnea at rest	1434	6.5	94	11.1	<.0001
Independent	21 421	98.0	798	94.8	<.0001
Poor functional statusd	448	2.1	44	5.2
Operative variables
Long fusion ≥4 levels	7222	32.8	307	36.2	.0377
Short fusion ≤3 levels	14 832	67.3	542	63.8
Pelvic fixation	231	1.1	13	1.5	.1779
Inpatient surgery	21 564	97.8	831	97.9	<.8435
Outpatient surgery	490	2.2	18	2.1
Operation in 2011	3321	15.1	105	12.4	.0549
Operation in 2012	4780	21.7	170	20.0
Operation in 2013	6220	28.2	261	30.7
Operation in 2014	7733	35.1	313	36.9
Extended operative time	6123	27.8	256	30.2	.1275

Abbreviation: ASA, American Society of Anesthesiologists. ^a Pulmonary comorbidity was defined as a history of chronic obstructive pulmonary disease of ventilator dependence within 48 hours prior to surgery.

^b Cardiac comorbidity was defined as the use of hypertensive medication or a history of chronic heart failure.

^c Renal comorbidity was defined as dialysis treatment within 2 weeks prior to surgery or acute renal failure within 24 hours prior to surgery.

^d Poor functional status was defined as partial or total dependence prior to surgery.