C-reactive protein as a non-linear predictor of prolonged length of intensive care unit stay after gastrointestinal cancer surgery

Table 1 Demographic and clinical characteristics of patients

Variables	ICU LoS < 72 h (n = 325), %	ICU LoS ≥ 72 h (n = 83), %	P value
Age (yr)	73.38 ± 11.31	74.18 ± 10.80	0.56
Sex			0.363
Male	218 (67.08)	60 (72.29)
Female	107 (32.92)	23 (27.71)
Laparoscopic surgery			0.221
No	250 (76.92)	69 (83.13)
Yes	75 (23.08)	14 (16.87)
Emergency surgery			0.004
No	275 (84.62)	59 (71.08)
Yes	50 (15.38)	24 (28.92)
Cancer site			0.896
Stomach	162 (49.84)	39 (46.99)
Rectum	41 (12.62)	11 (13.25)
Colon	102 (31.38)	26 (31.33)
Duodenum	20 (6.15)	7 (8.43)
ICU readmission			0.775
No	308 (94.77)	78 (93.98)
Yes	17 (5.23)	5 (6.02)
Tracheotomy			< 0.001
No	323 (99.38)	67 (80.72)
Yes	2 (0.62)	16 (19.28)
Mechanical ventilation			< 0.001
No	289(88.92)	42(50.60)
Yes	36(11.08)	41(49.40)
CRRT therapy			0.442
No	318 (97.85)	80 (96.39)
Yes	7 (2.15)	3 (3.61)
APACHE II scores	9.77 ± 4.31	12.34 ± 5.25	< 0.001
CRP values	3.95 ± 1.21	4.67 ± 0.88	< 0.001

ICU: Intensive care unit; CRRT: Continuous renal replacement therapy; APACHE: Acute Physiology and Chronic Health Evaluation; CRP: C-reactive protein.

Table 2 Multivariable regression analysis for associations between C-reactive protein levels and prolonged intensive care unit length of stay

Exposure variable	Crude model		Multivariable-adjusted model 1		Multivariable-adjusted model 2
	OR (95%CI)	P value	OR (95%CI)	P value	OR (95%CI)	P value
CRP	2.12 (1.52, 2.98)	< 0.001	2.30 (1.56, 3.38)	< 0.001	1.47 (1.00, 2.17)	0.014
Tertiles
T1	1.0	--	1.0	--	1.0	--
T2	2.19 (0.84, 5.74)	0.109	2.29 (0.78, 6.72)	0.130	2.43 (0.62, 9.47)	0.200
T3	8.13 (3.36, 19.66)	< 0.001	10.03 (3.61, 27.83)	< 0.001	6.51 (1.74, 24.34)	0.005
Trend analysis	3.02 (1.96, 4.65)	< 0.001	3.42 (2.07, 5.63)	< 0.001	2.57 (1.35, 4.88)	0.004

Model 1: Adjusted for age, gender, laparoscopic surgery; Model 2: Adjusted for age, gender, laparoscopic surgery, emergency surgery, cancer site, intensive care unit readmission, tracheotomy, continuous renal replacement therapy, mechanical ventilation therapy, Acute Physiology and Chronic Health Evaluation II score. OR: Odds ratio; CI: Confidence interval; CRRT: Continuous renal replacement therapy; APACHE: Acute Physiology and Chronic Health Evaluation.