Risk Factors for 28-Day Mortality in a Surgical ICU: A Retrospective Analysis of 347 Cases

Figures & data

Table 1 Demographic Data of the Patients Admitted to the Surgical ICU

Variables	Overall (n=347)	Survivors^a (n=234)	Nonsurvivors^b (n=113)	P value
Age (years)	60.88 ± 18.01	59.80 ± 17.71	61.13 ± 16.3	0.106
Sex (male/female)	219/128	146/88	73/40	0.689
Primary ICU diagnosis
Gastrointestinal, n (%)	162 (46.69)	114 (48.72)	48 (42.48)	0.275
Infection, n (%)	71 (20.46)	47 (20.09)	24 (21.24)	0.803
Trauma, n (%)	31 (8.93)	25 (10.68)	6 (5.31)	0.100
Respiratory, n (%)	31 (8.93)	20 (8.55)	11 (9.73)	0.716
Cardiovascular, n (%)	23 (6.63)	10 (4.27)	13 (11.50)	0.011^#
Neurologic, n (%)	17 (4.90)	11 (4.70)	6 (5.31)	0.805
Orthopedic, n (%)	7 (2.02)	3 (1.28)	4 (3.54)	0.161
Renal*, n (%)	5 (1.44)	4 (1.71)	1 (0.88)	0.546
Coexisting conditions
Smoking, n (%)	110 (31.70)	80 (34.19)	30 (26.55)	0.152
Chronic alcohol consumption, n (%)	80 (23.05)	59 (25.21)	21 (18.58)	0.169
Hypertension, n (%)	96 (27.67)	70 (29.91)	26 (23.01)	0.178
Diabetes mellitus, n (%)	44 (12.68)	28 (11.97)	16 (14.16)	0.565
Cirrhosis, n (%)	29 (8.36)	15 (6.41)	14 (12.39)	0.059
Ischemic heart disease, n (%)	33 (9.51)	19 (8.12)	14 (12.39)	0.204
Stroke, n (%)	44 (12.68)	30 (12.82)	14 (12.39)	0.910
Malignant diseases, n (%)	73 (21.04)	45 (19.23)	28 (24.78)	0.235
COPD, n (%)	39 (11.24)	22 (9.40)	17 (15.04)	0.119
Surgery, n (%)	109 (31.41)	73 (31.20)	36 (31.86)	0.901
Gastrointestinal surgery, n (%)	26 (7.49)	17 (7.26)	9 (7.96)	0.817
Thoracic Surgery, n (%)	9 (2.59)	6 (2.56)	3 (2.65)	0.960
Hepatobiliary and pancreatic Surgery, n (%)	58 (16.71)	37 (15.81)	21 (8.97)	0.517
Neurosurgery, n (%)	1 (0.29)	1 (0.43)	0 (0.00)	0.486
Orthopedic surgery, n (%)	11 (3.17)	10 (4.27)	1 (0.88)	0.091
Urologic surgery, n (%)	2 (0.58)	1 (0.43)	1 (0.88)	0.598
Gynecologic surgery	2 (0.58)	1 (0.43)	1 (0.88)	0.598
Emergency surgery, n (%)	16 (4.61)	11 (4.70)	5 (4.42)	0.909

Notes: ^aPatients survived longer than 28 days after leaving surgical ICU; ^bNonsurvivors included ICU mortality and 28-day mortality after leaving surgical ICU. *“Renal” means acute kidney injury (AKI). ^#P-value <0.05.

Abbreviation: COPD, chronic obstructive pulmonary disease.

Table 2 Clinical Characteristics of the Patients Admitted to the Surgical ICU

Variables	Overall (n=347)	Survivors (n=234)	Nonsurvivors (n=113)	P value
Symptoms at ICU admission
Fever, n (%)	34 (9.80)	25 (10.68)	9 (7.96)	0.425
Jaundice, n (%)	32 (9.22)	16 (6.84)	16 (14.16)	0.027^#
Hematemesis and hematochezia, n (%)	12 (3.46)	7 (2.99)	5 (4.42)	0.493
Nausea and vomiting, n (%)	6 (1.73)	4 (1.71)	2 (1.77)	0.968
Oliguria, n (%)	6 (1.73)	5 (2.14)	1 (0.88)	0.402
Disturbance of consciousness*, n (%)	89 (25.65)	45 (19.23)	44 (38.94)	<0.001^##
Signs at ICU admission
Body temperature (°C)	37.2 ± 0.97	37.2 ± 0.89	37.3 ± 1.12	0.136
Pulse rate (times per minute)	104 ± 26.2	103 ± 25.8	107 ± 27.7	0.173
Respiratory rate (times per minute)	24 ± 8.6	24 ± 9.0	25 ± 7.9	0.568
MAP (mmHg)	90 ± 17.9	91 ± 16.9	88 ± 19.8	0.101
Lab values at ICU admission
WBC (10^9/L)	12.9 ± 9.05	12.9 ± 9.53	12.7 ± 7.97	0.823
PLT (10^9/L)	146.8 ± 111.58	153.3 ± 112.44	132.8 ± 108.92	0.112
ALT (U/L)	186.8 ± 504.05	185.1 ± 489.98	233.4 ± 569.65	0.243
AST (U/L)	289.3 ± 934.09	255.4 ± 907.49	361.6 ± 988.98	0.328
TB (μmol/L)	79.6 ± 124.67	64.0 ± 102.40	112.9 ± 157.86	0.001^##
Albumin (g/L)	29.0 ± 6.81	29.4 ± 7.12	28.0 ± 6.03	0.085
PT (s)	18.5 ± 8.96	17.3 ±5.41	21.3 ± 13.72	<0.001^##
INR	1.6 ± 0.91	1.5 ± 0.63	1.9 ± 1.31	<0.001^##
Creatinine (μmol/L)	127.0 ± 131.52	128.0 ± 133.96	124.8 ± 126.66	0.836
Na^+ (mmol/L)	137.3 ± 7.78	136.9 ± 8.70	138.0 ± 9.65	0.218
K^+ (mmol/L)	4.0 ± 1.35	3.9 ± 0.71	4.1 ± 2.15	0.417
PaO2/FiO2 ^a	3.4 ± 2.92	3.5 ± 2.35	3.1 ± 3.88	0.256
Arterial lactate (mmol/L)	3.4 ± 4.14	2.4 ± 2.76	5.7 ± 5.55	<0.001^##
Procalcitonin (ng/mL)^b	16.1 ± 36.22	15.6 ± 36.90	17.4 ± 34.49	0.703
Positive blood bacterial culture^c, n (%)	52 (27.66)	34 (26.26)	18 (30.51)	0.555
APACHE II at ICU admission	16.39 ± 7.61	14.18 ± 8.15	20.96 ± 8.31	<0.001^##
SOFA score at ICU admission	7.67 ± 4.87	8.18 ± 3.57	10.76 ± 5.71	<0.001^##

Notes: ^aSurvivors (n = 214), nonsurvivors (n = 99); ^bSurvivors (n = 205), nonsurvivors (n = 76). ^cSurvivors (n =129), nonsurvivors (n = 59). *“Yes” in “disturbance of consciousness” was given when the patient has difficulty maintaining wakefulness and/or has impaired awareness of him/herself and his/her environment. ^#P-value <0.05, ^##P-value <0.01. 

Abbreviations: HCT, hematocrit; WBC, white blood cell count; PLT, platelet count; ALT, alanine aminotransferase; AST, alanine aminotransferase; TB, total bilirubin; PT, prothrombin time; INR, international normalized ratio; PaO₂/FiO₂, oxygen partial pressure/oxygen concentration; MAP, mean arterial pressure; APACHE II, acute physiology and chronic health evaluation; SOFA score, sequential organ failure assessment score.

Table 3 Univariate and Multivariate Analyses of 28-Day Mortality

Parameters	Univariate Analysis		Multivariate Analysis
	OR (95% CI)	P value	OR (95% CI)	P value	VIF
Age (≥65y/<65y)	1.627(1.036–2.557)	0.035^#	2.899(1.427–5.890)	0.003^##	1.300
Sex (male/female)	1.100(0.689–1.756)	0.690	–	–
Smoking (yes/no)	1.447(0.880–2.379)	0.146	1.003(0.507–1.986)	0.993	1.044
Chronic alcohol consumption (yes/no)	1.477(0.845–2.581)	0.171	1.148(0.515–2.562)	0.736	1.079
Hypertension (yes/no)	1.428(0.849–2.402)	0.179	3.630(1.545–8.531)	0.003^##	1.236
Diabetes mellitus (yes/no)	0.824(0.426–1.594)	0.565	–	–
Cirrhosis (yes/no)	0.484(0.225–1.042)	0.064	0.558(0.185–1.683)	0.300	1.222
Ischemic heart disease (yes/no)	0.625(0.301–1.297)	0.207	–	–
Stroke (yes/no)	1.040(0.528–2.049)	0.910	–	–
Malignant diseases (yes/no)	0.723(0.423–1.236)	0.236	–	–
COPD	0.586(0.298–1.154)	0.122	0.907(0.348–2.367)	0.842	1.188
Bacterial culture of blood (yes/no)^a	0.812(0.439–1.503)	0.508	–	–	–
SOFA score at ICU admission	1.310(1.222–1.405)	<0.001^##	1.289(1.131–1.469)	<0.001^##	3.234
APACHE II at ICU admission (w/o age)*	1.139(1.099–1.181)	<0.001^##	1.028(0.967–1.093)	0.378	2.347
Surgery	0.970(0.598–1.572)	0.901	–	–
Emergency surgery	1.065(0.361–3.143)	0.909	–	–
PLT (10^9/L)	0.998(0.996–1.000)	0.114	1.004(1.001–1.007)	0.015^#	1.357
WBC (10^9/L)	0.997(0.972–1.023)	0.822	–	–
TB	1.003(1.001–1.005)	0.001^##	1.000(0.997–1.003)	0.961	1.477
Creatinine	1.000(0.998–1.002)	0.836	–	–
Albumin	0.969(0.935–1.004)	0.086	0.970(0.920–1.022)	0.251	1.124
PT	1.064(1.025–1.105)	0.001^##	0.966(0.882–1.059)	0.461	7.166
Na^+	1.019(0.989–1.049)	0.220	–	–
K^+	1.069(0.905–1.262)	0.432	–	–
INR	1.742(1.256–2.415)	0.001^##	1.210(0.438–3.340)	0.713	7.045
PaO2/FiO2 ^b	0.940(0.843–1.048)	0.265	–	–
Arterial lactate	1.253(1.156–1.358)	<0.001^##	1.186(1.088–1.293)	<0.001^##	1.301
Procalcitonin ^c	1.001(0.994–1.008)	0.702	–	–
Blood transfusion (yes/no)	0.838(0.529–1.327)	0.450	–	–

Notes: *Since age is a factor in calculating APACHE II scores, they cannot be used together with age in multivariable analysis. Therefore, APACHE II scores without age were used here. ^aSurvivors (n =129), nonsurvivors (n = 59); ^bSurvivors (n = 214), nonsurvivors (n = 99); ^cSurvivors (n = 205), nonsurvivors (n = 76). ^#P-value <0.05, ^##P-value <0.01. 

Abbreviations: COPD, chronic obstructive pulmonary disease; SOFA score, sequential organ failure assessment score; PLT, platelet count; WBC, white blood cell count; TB, total bilirubin; INR, international normalized ratio; PaO₂/FiO₂, oxygen partial pressure/oxygen concentration.

Table 4 Clinical Outcomes for Young and Elderly SICU Patients

Variables	Overall (n=347)	The Young (<65y, n=191)	The Elderly (≥65y, n=156)	P value
Maximum APACHE II	18.53 ± 8.56	16.97 ± 8.20	20.44 ± 8.64	<0.001^##
Maximum APACHE II (w/o age)	13.20 ± 9.34	13.02 ± 9.30	13.42 ± 9.40	0.691
Maximum SOFA score	8.75 ± 5.66	8.42 ± 6.00	9.158 ± 5.21	0.237
APACHE II at discharge	16.61 ± 9.64	14.70 ± 9.45	18.9 ± 9.38	<0.001^##
APACHE II at discharge (w/o age)	15.12 ± 8.35	15.29 ± 8.10	14.90 ± 8.67	0.670
SOFA score at discharge	8.44 ± 5.79	8.06 ± 6.08	8.91 ± 5.40	0.173
Complications
Sepsis, n (%)	43 (12.39)	24 (12.57)	19 (12.18)	0.914
Sepsis shock, n (%)	14 (4.03)	2 (0.10)	12 (7.69)	0.002^##
AKI, n (%)	53 (15.27)	30 (15.71)	23 (14.74)	0.804
ALI, n (%)	32 (9.22)	21 (10.99)	11 (7.05)	0.207
ARDS, n (%)	39 (11.24)	12 (6.28)	27 (17.31)	0.001^##
ACS, n (%)	33 (9.51)	5 (2.62)	28 (17.95)	<0.001^##
DIC, n (%)	5 (1.44)	3 (1.57)	2 (1.28)	0.822
MODS, n (%)	56 (16.14)	27 (14.14)	29 (18.59)	0.262
Length of hospital stay (days)	14.12 ± 14.38	14.72 ± 14.30	14.39 ± 14.48	0.392
Length of ICU stay (days)	10.85 ± 12.82	11.91 ± 13.34	9.56 ± 12.08	0.091
ICU re-admission, n (%)	48 (13.83)	22 (11.52)	26 (16.66)	0.167
ICU mortality, n (%)	61 (17.58)	29 (15.18)	32 (20.51)	0.194
28-day mortality, n (%)^a	113 (32.56)	53 (27.75)	60 (38.46)	0.034^#

Notes: ^a28-day overall mortality included ICU mortality and 28-day mortality after leaving ICU. ^#P-value <0.05, ^##P-value <0.01. 

Abbreviations: APACHE II, acute physiology and chronic health evaluation; SOFA score, sequential organ failure assessment score; AKI, acute kidney injury; ALI, acute liver injury; ARDS, acute respiratory distress syndrome; ACS, acute coronary syndrome; DIC, disseminated intravascular coagulation; MODS, multiple organ dysfunction syndrome; ICU, intensive care unit.