Perioperative hyperglycemia is associated with postoperative neurocognitive disorders after cardiac surgery

Figures & data

Table 1 Patient characteristics by postoperative neurocognitive outcome results among those with no prior cognitive disorders (N=855)

Study variable	Event (N=271)	No-event (N=562)	Death (N=22)	P-value
Duration of follow-up in years (mean, SD)	4.04 (1.35)	4.08 (1.58)	0.04 (0.03)	<0.001
Age (mean, SD)	66.0 (12.2)	66.5 (11.1)	69.6 (14.1)	0.36
Female sex	88 (32.5)	125 (22.2)	7 (31.8)	0.005
NYHA class of HF (n, %); 85% known*
Class 1	13 (5.1)	20 (4.4)	0 (0.0)	0.006
Class 2	57 (22.4)	144 (31.9)	1 (5.3)
Class 3	145 (56.9)	225 (49.9)	11 (57.9)
Class 4	40 (15.7)	62 (13.7)	7 (36.8)
Number of diseased coronary vessels (n, %)
None	52 (19.2)	142 (25.3)	5 (23.7)	0.08
One	22 (8.1)	37 (6.6)	4 (19.1)
Two	40 (14.8)	100 (17.8)	4 (19.1)
Three	157 (57.9)	283 (50.4)	8 (38.1)
Aortic occlusion (n, %)	83 (30.6)	235 (41.8)	17 (77.3)	<0.001
Cardiopulmonary bypass (n, %)	113 (41.7)	271 (48.2)	20 (90.9)	<0.001
Resuscitation after cardiac arrest (n, %)	0 (0.0)	9 (1.6)	1 (5.0)	0.04
ICU length of stay in days (median, IQR)	2 (1.0–3)	2 (1.0–3)	3 (1–13)	0.25
Intra-operative Blood Products applied (n, %) – 83% known*	75 (27.7)	175 (31.1)	13 (59.1)	0.009
Comorbidities
Diabetes mellitus (n, %)	90 (33.3)	175 (31.1)	9 (45.0)	0.37
Infectious endocarditis (n, %)	5 (1.8)	8 (1.4)	1 (5.0)	0.64
Immunosuppressive therapy (n, %)	0 (0.0)	3 (0.5)	1 (5.0)	0.006
Hypertension (n, %)	196 (72.6)	406 (72.2)	16 (76.2)	0.91
Peripheral vascular disease (n, %)	24 (8.9)	47 (8.4)	1 (5.0)	0.82
Cerebrovascular disease (n, %)	21 (7.8)	23 (4.1)	0 (0.0)	0.04
Cardiac arrhythmia (n, %)	28 (10.3)	84 (15.0)	4 (18.2)	0.15
Among those who had blood transfusion
# units FFP (median, IQR)	0 (0–4)	0 (0–1)	2 (0–8)	0.002
# units RBC (median, IQR)	2 (2–4)	2 (1–3)	3 (2–8)	0.01
Perioperative glucose
First glucose (median, IQR)	116 (102–141)	113 (100–133)	128.5 (116–158)	0.02
Median glucose (median, IQR)	135 (121–155)	131 (119–148)	151.5 (134–185)	0.005
Peak glucose (median, IQR)	171 (148–204)	167 (142–199)	203.5 (157–247)	0.01
Glucose range (median, IQR)	59 (37–95)	58 (37–95)	80.5 (61–132)	0.05

Notes: Data are presented as number, mean, median, percentage, or range.

* Percentage of patients with information in medical record.

Abbreviations: DM, diabetes mellitus; FFP, fresh frozen plasma; HF, heart failure; ICU, intensive care unit; IQR, interquartile range; NYHA, New York Heart Association; RBC, red blood cell; SD, standard deviation.

Table 2 Multivariate Cox regression results showing risk factors for postoperative neurocognitive disorders

Variable	Level	Hazard ratio (95% CI)	P-value
Age at surgery	In years	1.04 (1.03–1.06)	<0.001
Sex	Female versus male	4.18 (1.33–13.14)	0.01
Age * sex	For female	1.04 (1.03–1.05)	<0.001
Heart failure classification	2 versus 1	0.43 (0.2–0.91)	0.03
	3 versus 1	3.48 (1.72–7.05)	<0.001
	4 versus 1	4.95 (2.41–10.13)	<0.001
Cardiopulmonary bypass (CPB)	Yes versus no	1.17 (0.82–1.68)	0.38
Cardiopulmonary bypass * sex	CPB versus no CPB for males	15.6 (11.2–21.9)	<0.001
Diabetes mellitus	Yes versus no	1.24 (1.08–1.43)	0.002
Infectious endocarditis	Yes versus no	1.44 (1.11–1.87)	0.006
Cardiac arrhythmia	Yes versus no	1.06 (0.91–1.22)	0.46
Intraoperative blood products (BPR)	Yes versus no	2.04 (1.77–2.35)	<0.001
Aortic occlusion	Yes versus no	0.54 (0.43–0.68)	<0.001
ICU stay	In days	1.08 (1.07–1.09)	<0.001
Number of diseased coronary vessels	1 versus 0	0.4 (0.29–0.55)	<0.001
	2 versus 0	1.71 (1.41–2.06)	<0.001
	3 versus 0	0.99 (0.82–1.20)	0.91
First glucose	In 20 units	1.16 (1.13–1.2)	<0.001

Abbreviations: CI, confidence interval; ICU, intensive care unit.

Figure 1 Cox-proportional hazard survival curves with competing risk for study outcome (adjusted for possible risk factors).*

Note: *The estimated time point where these two glucose levels begin to be statistically significant is at 379 days post-surgery (P=0.03).