Predicting acute kidney injury in septic shock patients using inflammatory indices in the intensive care unit

Table 1 Univariate Analysis of Baseline Characteristics in Septic Shock Patients with and without acute kidney injury, mean (95%CI)

Variables	Without AKI (n = 5108)	With AKI (n = 6552)	P value
Age (years)	67 (55-79)	69 (58-79)	< 0.001
Body mass index (kg/m2)	26.3 (22.3-31.6)	27.3 (23.0-33.2)	< 0.001
Sequential Organ Failure Assessment on admission	6 (4-9)	7 (5-10)	< 0.001
White blood counts (× 103 cells/L)	13.0 (8.6-18.4)	14.0 (9.4-19.7)	< 0.001
Platelet count (× 103 cells/L)	220 (156-298)	211 (149-294)	< 0.001
Lymphocyte count (× 103 cells/L)	962 (557-1578)	930 (534-1560)	0.023
Neutrophil count (× 103 cells/L)	10.3 (6.3-15.1)	11.3 (7.0-16.4)	< 0.001
Monocytes (× 103 cells/L)	7.4 (4.1-11.5)	7.7 (4.3-12.1)	0.003
Neutrophil-to-lymphocyte ratio	10.1 (5.2-18.2)	11.4 (6.1-22.0)	< 0.001
Platelet-to-lymphocyte ratio	226 (132-378)	222 (130-391)	0.949
Monocyte-to-lymphocyte ratio	0.7 (0.4-1.2)	0.8 (0.4-1.3)	< 0.001
Sodium (mmol/L)	136 (133-139)	136 (132-140)	0.008
Potassium (mmol/L)	4.0 (3.7-4.5)	4.2 (3.7-4.8)	< 0.001
Magnesium (mg/dL)	1.8 (1.5-2.0)	1.8 (1.5-2.1)	< 0.001
Albumin (g/dL)	3.1 (2.6-3.6)	3.1 (2.6-3.6)	< 0.001
Initial lactate (mmol/L)	2.1 (1.3-3.4)	2.4 (1.5-3.9)	< 0.001
Initial international normalized ratio	1.2 (1.1-1.5)	1.3 (1.1-1.6)	< 0.001
Initial alanine aminotransferase (U/L)	25 (22-28)	25 (16-45)	0.751
Initial aspartate aminotransferase (U/L)	29 (19-51)	30 (20-57)	< 0.001
Bicarbonate (mmol/L)	25 (22-28)	23 (20-27)	< 0.001
Chloride (mmol/L)	101 (97-104)	100 (96-105)	< 0.001
Blood urea nitrogen (mg/dL)	20 (14-31)	34 (22-53)	< 0.001
Lactate-albumin ratio	0.7 (0.4-1.1)	0.8 (0.5-1.4)	< 0.001
Creatinine (mg/dL)	0.91 (0.70-1.30)	1.8 (1.2-3.0)	< 0.001
Total bilirubin (mg/dL)	0.6 (0.4-1.1)	0.7 (0.4-1.2)	0.004
Hemoglobin (g/dL)	11.9 (10.0-13.5)	11.5 (9.8-13.2)	< 0.001
Systemic immune-inflammation index	2185 (995-4393)	2413 (1131-4838)	< 0.001
Neutrophil-percentage-to-albumin ratio	25.5 (21.1-31.3)	26.0 (21.8-32.2)	< 0.001
Systemic inflammation response index	7072 (2760-15160)	8216 (3390-18048)	< 0.001
Aggregate index of systemic inflammation (× 109/L)	1.53 (0.50-3.83)	1.72 (0.59-4.32)	< 0.001

AKI: Acute kidney injury.

Table 2 Baseline demographic and Clinical characteristics of intensive care unit patients with septic shock, n (%)

	Without AKI	With AKI	P value	OR	95%CI for OR
Male gender	2523 (49.4)	3428 (52.3)	0.002	1.124	1.045	1.210
Ethnicity
African American	436 (8.5)	762 (11.6)	< 0.001
Asian	96 (1.9)	123 (1.9)
Caucasian	3989 (78.1)	4891 (74.6)
Hispanic	259 (5.1)	376 (5.7)
Native American	33 (0.6)	32 (0.5)
Other	294 (5.8)	368 (5.6)
Hypertension	473 (9.8)	619 (9.4)	0.730	1.022	0.902	1.159
Diabetes	88 (1.7)	203 (3.1)	< 0.001	1.824	1.416	2.349
Chronic obstructive pulmonary disease	512 (10)	586 (8.9)	0.048	0.882	0.778	0.999
Hyperlipidemia	94 (1.8)	193 (2.9)	< 0.001	1.619	1.262	2.077
Cerebrovascular disease	84 (1.6)	135 (2.1)	0.101	1.258	0.956	1.656
Malignancy	342 (6.7)	304 (4.6)	< 0.001	0.678	0.578	0.795
Chronic kidney disease	259 (5.1)	1154 (17.6)	< 0.001	4.002	3.479	4.605
Cardiomyopathy	10 (0.2)	19 (0.3)	0.311	1.483	0.689	3.191
Heart failure	460 (9.0)	679 (10.4)	0.014	1.168	1.031	1.323
Immunosuppression	315(6)	271(4)	0.0001	0.65	0.55	0.77
Cirrhosis	128 (2.6)	144 (2.2)	0.245	0.867	0.681	1.103
Corticosteroids	656 (12.8)	729 (11.1)	0.004	0.850	0.759	0.951
Ventilation	2155 (42.2)	2997 (45.7)	< 0.001	1.155	1.073	1.244
Diuretics	712 (13.9)	1185 (18.1)	< 0.001	1.363	1.232	1.508
Angiotensin converting enzyme inhibitor	345 (6.8)	602 (9.2)	< 0.001	1.397	1.217	1.603
Angiotensin 2 receptor antagonist	119 (2.3)	199 (3.0)	0.020	1.313	1.043	1.653
Vasopressors	1576 (30.9)	2975 (45.4)	< 0.001	1.864	1.726	2.013

AKI: Acute kidney injury; OR: Odds ratio.

Table 3 Multivariate logistic regression with forward selection of risk factors associated with acute kidney injury

		β	SE	P value	Odds ratio	95%CI for EXP(β)
						Lower	Upper
Model 1	SOFA score	0.04	0.01	0.005	1.04	1.01	1.06
	Blood urea nitrogen	0.01	0.003	< 0.001	1.01	1.00	1.01
	Serum creatinine	1.24	0.07	< 0.001	3.46	3.00	4.00
	Neutrophils	0.001	0.0001	< 0.001	1.00	1.00	1.00
	Monocytes	0.001	0.001	0.09	1.00	1.00	1.00
	Potassium	-0.164	0.05	0.001	0.85	0.76	0.94
	Total bilirubin	-0.05	0.016	0.002	0.95	0.92	0.98
	ACEi	0.44	0.15	0.003	1.56	1.16	2.08
	Vasopressors	0.16	0.01	0.09	1.17	0.98	1.41
Model 2	Caucasian	-0.075	0.027	0.005	0.93	0.88	0.98
	Malignancy	-0.41	0.12	< 0.001	0.66	0.52	0.83
	Immunosuppression	-0.26	0.12	0.034	0.76	0.60	0.98
	CKD	1.23	0.10	< 0.001	3.40	2.82	4.19
	Vasopressors	0.44	0.06	< 0.001	1.55	1.39	1.73
	Diabetes	0.55	0.20	0.006	1.74	1.17	2.58
	ACEi	0.45	0.10	< 0.001	1.58	1.29	1.93
	A2RB	0.51	0.18	0.005	1.68	1.16	2.41
	Factor 1 (inflammatory/hematologic)	0.10	0.03	< 0.001	1.10	1.04	1.17
	Factor 2 (metabolic/renal/inflammatory)	0.26	0.03	< 0.001	1.30	1.23	1.39
Model 3	Caucasian	0.37	0.10	< 0.001	1.44	1.19	1.74
	Malignancy	-0.39	0.12	0.001	0.68	0.54	0.85
	Immunosuppression	-0.27	0.13	0.034	0.77	0.60	0.98
	CKD	1.19	0.10	< 0.001	3.29	2.70	4.01
	Vasopressors	0.30	0.07	< 0.001	1.35	1.19	1.54
	Diabetes	0.56	0.20	0.006	1.75	1.18	2.59
	ACEi	0.47	0.10	< 0.001	1.60	1.30	1.96
	A2RB	0.52	0.19	0.005	1.69	1.17	2.43
	Factor 1 (Inflammatory/hematologic)	0.12	0.03	< 0.001	1.13	1.06	1.20
	Factor 2 (metabolic/renal/inflammatory)	0.24	0.03	< 0.001	1.27	1.19	1.34
	SOFA score	0.04	0.01	< 0.001	1.04	1.01	1.05

ACEi: Angiotensin converting enzyme inhibitor; A2RB: Angiotensin 2 receptor antagonist; CKD: Chronic kidney disease; SOFA: Sequential Organ Failure Assessment.