High serum cortisol level is associated with increased risk of delirium after coronary artery bypass graft surgery: a prospective cohort study

Table 2 Preoperative variables

Variable	All enrolled patients (n = 243)	Non-delirious patients (n = 120)	Delirious patients (n = 123)	P value
Age, years	61.0 ± 8.3	58.3 ± 8.0	63.6 ± 7.7	< 0.001
Body mass index, kg/m²	26.1 ± 3.5	26.2 ± 3.9	26.0 ± 3.0	0.643
Education, years	10.4 ± 4.4	10.4 ± 4.3	10.4 ± 4.4	0.992
Female gender	43 (17.7%)	21 (17.5%)	22 (17.9%)	0.937
Previous medical history
Hypertension	161 (66.3%)	75 (62.5%)	86 (69.9%)	0.221
Previous myocardial infarction^a	114 (46.9%)	55 (45.8%)	59 (48.0%)	0.739
Diabetes mellitus	89 (36.6%)	36 (30.0%)	53 (43.1%)	0.034
Hyperlipidemia	96 (39.5%)	47 (39.2%)	49 (39.8%)	0.915
Arrhythmia	58 (23.9%)	26 (21.7%)	32 (26.0%)	0.426
Stroke	31 (12.8%)	11 (9.2%)	20 (16.3%)	0.097
COPD	6 (2.5%)	1 (0.8%)	5 (4.1%)	0.213
Renal dysfunction^b	9 (3.7%)	4 (3.3%)	5 (4.1%)	1.000
Chronic smoking^c	79 (32.5%)	40 (33.3%)	39 (31.7%)	0.787
Alcoholism^d	34 (14.0%)	21 (17.5%)	13 (10.6%)	0.119
Habitual benzodiazepine use	23 (9.5%)	12 (10.0%)	11 (8.9%)	0.778
Previous general anesthesia	17 (7.0%)	9 (7.5%)	8 (6.5%)	0.761
Preoperative LVEF, percentage^e	58.0 ± 9.6	59.4 ± 8.4	56.7 ± 10.5	0.024
Preoperative CCS class				0.736
I	53 (21.8%)	24 (20.0%)	29 (23.6%)
II	126 (51.9%)	63 (52.5%)	63 (51.2%)
III	53 (21.8%)	26 (21.7%)	27 (22.0%)
IV	11 (4.5%)	7 (5.8%)	4 (3.3%)
Preoperative NYHA functional class				0.089
I	77 (31.7%)	45 (37.5%)	32 (26.0%)
II	131 (53.9%)	62 (51.7%)	69 (56.1%)
III	35 (14.4%)	13 (10.8%)	22 (17.9%)
Preoperative EuroSCORE score	2.6 ± 2.1	2.0 ± 1.8	3.2 ± 2.1	< 0.001

Data are presented as mean ± standard deviation or number of patients (percentage). ^aMyocardial infarction of more than 1 month before surgery. ^bSerum creatinine of greater than 177 μmol/L. ^cSmoking of more than 20 cigarettes per day within 1 month. ^dConsumption of an equivalent of 150 mL of alcohol per week. ^eResults of echocardiography (Simpson's method). CCS, Canadian Cardiovascular Association; COPD, chronic obstructive pulmonary disease; EuroSCORE, European System for Cardiac Operative Risk Evaluation; LVEF, left ventricular ejection fraction; NYHA, New York Heart Association.

ISSN: 1364-8535