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

Table 4 Predictors of postoperative delirium.

Variable	Univariate analyses^a	Multivariate logistic regression analysis^b
	P value	Odds ratio (95% CI)	P value
Age, years	< 0.001	1.111 (1.065-1.159)	< 0.001
History of diabetes mellitus	0.035	1.905 (1.001-3.622)	0.049
Preoperative LVEF, percentage	0.026	-	-
Preoperative NYHA functional class	0.029	-	-
Preoperative EuroSCORE score	< 0.001	-	-
Duration of surgery, hours	0.013	1.360 (1.010-1.831)	0.043
Duration of anesthesia, hours^c	0.020	-	-
Blood transfusion of at least 400 mL during surgery	0.048	-	-
Postoperative APACHE II score	< 0.001	-	-
Serum cortisol concentration, nmol/L^c	< 0.001	-	-
Serum cortisol level, every level increase^d	< 0.001	3.091 (1.763-5.418)	< 0.001
Postoperative LVEF, percentage	0.009	-	-
Postoperative cardiac insufficiency^c	0.015	-	-
Postoperative arrhythmia^c	0.065	-	-
Postoperative complications within 1 day^e	0.001	2.485 (1.184-5.214)	0.016
Postoperative complications within 5 days^c,e	< 0.001	-	-
Postoperative complications within 28 days^c,e	< 0.001	-	-

^aOccurrence of postoperative delirium was modeled as a function of a single predictor. ^bOccurrence of postoperative delirium was modeled as a function of all predictors that differed (P < 0.10) in the univariate analyses. Excluded were nine cases with missing values for at least one of the risk factors in the model. Multivariate logistic regression analysis was performed by using a forward (conditional) stepwise procedure. ^cVariable was not included in the multiple logistic regression analysis. ^dThe normal range is 138 to 690 nmol/L. Level 1 indicates a serum cortisol concentration of less than 138 nmol/L, level 2 between 138 and 690 nmol/L, and level 3 of greater than 690 nmol/L. ^eComplications that occurred before or during the 1st, 5th, or 28th postoperative day. APACHE II, Acute Physiology and Chronic Health Evaluation II; CI, confidence interval; EuroSCORE, European System for Cardiac Operative Risk Evaluation; LVEF, left ventricular ejection fraction; NYHA, New York Heart Association.

ISSN: 1364-8535