Correlation between neutrophil-to-lymphocyte ratio and contrast-induced acute kidney injury and the establishment of machine-learning-based predictive models

Figures & data

Figure 1. Study Technical flowchart.

Figure 2. The ROC curve of NLR for prediction of CI-AKI.

Table 1. Baseline characteristics of study subjects.

	AKI group (n = 120)	Non AKI group (n = 2110)	p value
Age (year)	75.00 (67.25,81.00)	70.00 (61.00,78.00)	<0.001
Female [n(%)]	54 (45.00%)	617 (29.20%)	<0.001
Body Mass Index(kg/m^2)	23.10 (20.83,24.99)	23.20 (20.81,25.51)	0.497
Systolic blood pressure (mmHg)	142.50 (128.25,160.25)	136.00 (122.75,150.00)	0.003
Diastolic blood pressure(mmHg)	74.50 (63.00,86.00)	75.00 (67.00,83.00)	0.530
Heart rate (times/min)	78.00 (70.00,87.00)	75.00 (67.00,83.00)	0.242
Hypertension[n (%)]	95 (79.20%)	1355 (64.20%)	0.001
Diabetes [n (%)]	45 (37.50%)	523 (24.80%)	0.002
Hyperlipidemia [n (%)]	10 (8.30%)	103 (4.90%)	0.094
Atrial fibrillation [n (%)]	22 (18.30%)	231 (10.90%)	0.013
Coronary heart disease[n (%)]	46 (38.30%)	469 (22.20%)	<0.001
Heart failure [n (%)]	21 (17.50%)	105 (5.00%)	<0.001
Stroke [n (%)]	15 (12.50%)	283 (13.40%)	0.775
CKD [n (%)]	15 (12.50%)	62 (2.90%)	<0.001
COPD [n (%)]	5 (4.20%)	54 (2.60%)	0.286
Chronic liver diseases [n (%)]	4 (3.30%)	43 (2.20%)	0.337
Smoking [n (%)]	25 (20.80%)	556 (26.40%)	0.334
Thiazide diuretics [n (%)]	21 (17.50%)	245 (11.60%)	0.053
Loop diuretics [n (%)]	29 (25.20%)	150 (7.10%)	<0.001
Spironolactone [n (%)]	34 (28.30%)	157 (7.40%)	<0.001
ACEIs [n (%)]	13 (10.8%)	134 (6.40%)	0.054
ARBs [n (%)]	53 (44.20%)	624 (29.60%)	0.001
Aspirin [n (%)]	69 (57.50%)	1142 (54.10%)	0.470
Antiplatelet [n (%)]	60 (50.00%)	1037 (49.10%)	0.856
warfarin [n (%)]	13 (10.80%)	106 (5.00%)	0.006
Low molecular weight heparin [n (%)]	31 (25.80%)	377 (17.90%)	0.028
Statins [n (%)]	76 (63.30%)	1172 (55.50%)	0.095
Antibiotics [n (%)]	19 (15.80%)	374 (17.70%)	0.597
CCBs[n (%)]	47 (39.20%)	815 (38.60%)	0.906
β receptor blockers [n (%)]	36 (30.00%)	401 (19.00%)	0.003
α receptor blockers [n (%)]	2 (1.700%)	10 (0.50%)	0.273
Thioureas [n (%)]	11 (9.20%)	182 (8.60%)	0.838
Biguanides [n (%)]	19 (15.80%)	214 (10.10%)	0.047
Insulin [n (%)]	18 (15.00%)	168 (8.00%)	0.007
Hemoglobin (g/L)	117.50 (108.00,133.00)	130.00 (118.00,142.00)	<0.001
NLR	3.38 (2.60,5.35)	2.79 (1.98,4.18)	<0.001
WBC(×10^9 /L)	7.40 ± 0.54	7.60 ± 0.49	0.802
INR	1.10 ± 0.31	1.12 ± 0.33	0.405
Albumin (g/L)	38.35 (35.95,42.20)	39.80 (36.20,43.20)	0.047
Fasting plasma glucose(mmol/L)	5.82 (4.98,8.31)	5.20 (4.56,6.66)	<0.001
Triglycerides (mmol/L)	1.69 (1.04,3.16)	1.56 (1.04,3.35)	0.980
Total cholesterol (mmol/L)	3.87 (2.41,4.82)	3.71 (1.96,4.73)	0.721
HDL-C(mmol/L)	1.24 (0.99,1.64)	1.26 (1.01,1.75)	0.581
LDL-C (mmol/L)	2.28 (1.50,2.95)	2.20 (1.51,2.93)	0.518
Serum creatinine (μmol/L)	85.60 (65.35,118.50)	70.70 (58.40,85.90)	<0.001
Blood urea nitrogen(mmol/L)	6.75 (5.38,8.62)	5.58 (4.48,7.02)	<0.001
Uric acid (μmol/L)	350.05 (281.80,430.65)	343.10 (279.15,418.85)	0.210
GFR[ml·min^-1·(1.73 m^2)^-1]	71.79 (47.03,102.41)	95.13 (74.56,114.82)	<0.001
Proteinuria [n (%)]	22 (18.30%)	197 (9.30%)	0.001
Carotid plaque[n (%)]	61 (50.80%)	810 (38.40%)	0.007
Contrast volume (mL)	123.13 ± 65.77	119.22 ± 60.12	0.422

AKI: acute kidney injury; CKD: chronic kidney disease; COPD: chronic obstructive pulmoriary disease; ACEI: angiotensin-converting enzyme inhibitor; ARB: angiotensin receptor blocker; CCB: calcium calcium entry blocker; NLR: neutrophil-to-lymphocyte ratio; HDL-C: high-density lipoprotein-cholesterol; LDL-C: low-density lipoprotein–cholesterol; GFR estimated glomerular filtration rate.

Table 2. Univariable logistic regression analysis of factors associated with CI-AKI.

	B	S.E	Wald	OR	95%CI	P
Age	0.031	0.009	13.097	1.032	1.014 ∼ 1.049	<0.001
Female gender	0.683	0.190	12.972	1.980	1.365 ∼ 2.871	<0.001
Systolic blood pressure	0.014	0.004	10.597	1.014	1.006 ∼ 1.023	0.001
Hypertension	0.750	0.229	10.701	2.117	1.351 ∼ 3.319	0.001
Diabetes	0.599	0.195	9.424	1.821	1.242 ∼ 2.669	0.002
Atrial fibrillation	0.602	0.246	5.991	1.826	1.127 ∼ 2.957	0.014
Coronary heart disease	0.777	0.195	15.891	2.175	1.484 ∼ 3.187	<0.001
Heart failure	1.399	0.260	28.885	4.051	2.432 ∼ 6.746	<0.001
CKD	1.552	0.305	25.939	4.719	2.597 ∼ 8.573	<0.001
ARBs	0.633	0.190	11.119	1.884	1.298 ∼ 2.733	0.001
Loop diuretics	1.427	0.229	38.651	4.164	2.656 ∼ 6.529	<0.001
Spironolactone	1.593	0.219	52.947	4.918	3.202 ∼ 7.553	<0.001
β Receptor blockers	−0.602	0.207	8.486	1.827	1.218 ∼ 2.739	0.004
Biguanides	0.511	0.260	3.853	1.667	1.001 ∼ 2.776	0.050
Insulin	0.713	0.268	7.076	2.040	1.206 ∼ 3.449	0.008
Warfarin	0.832	0.310	7.188	2.297	1.251 ∼ 4.219	0.007
Low molecular weight heparin	0.471	0.216	4.742	1.601	1.048 ∼ 2.446	0.029
Proteinuria	0.779	0.248	9.914	2.180	1.342 ∼ 3.541	0.002
Carotid plaque	0.506	0.188	7.256	1.659	1.148 ∼ 2.399	0.007
Hemoglobin	−0.021	0.004	27.846	0.979	0.971 ∼ 0.987	<0.001
Albumin	−0.032	0.019	2.856	0.969	0.934 ∼ 1.005	0.091
Fasting plasma glucose	0.098	0.025	14.955	1.103	1.049 ∼ 1.158	<0.001
Serum Creatinine	0.003	0.001	7.713	1.003	1.001 ∼ 1.004	0.005
Blood urea nitrogen	0.004	0.005	0.625	1.004	0.994 ∼ 1.014	0.429
GFR	−0.018	0.003	32.675	0.982	0.976 ∼ 0.988	<0.001
NLR	0.085	0.024	12.303	1.088	1.038 ∼ 1.141	<0.001

CI-AKI: contrast-induced acute kidney injury; CKD: chronic kidney disease; ARB: Angiotensin receptor blocker; NLR: Neutrophil-to-lymphocyte ratio; GFR estimated glomerular filtration rate.

Table 3. Multivariable logistic regression analysis of CI-AKI.

	B	S.E	Wald	OR	95%CI	P
NLR (>2.844)	0.835	0.216	14.887	2.304	1.508 ∼ 3.521	<0.001
Female	0.381	0.216	5.903	1.667	1.104 ∼ 2.519	0.015
Systolic blood pressure	0.013	0.005	8.326	1.013	1.004 ∼ 1.022	0.004
CKD	0.854	0.362	5.568	2.347	1.156 ∼ 4.762	0.018
Spironolactone	10.300	0.235	30.561	3.676	2.315 ∼ 5.814	<0.001
ARBs	0.406	0.202	4.043	1.501	1.010 ∼ 2.232	0.044
Low molecular weight heparin	0.538	0.229	5.527	1.712	1.094 ∼ 2.681	0.019
eGFR	−0.007	0.003	4.220	0.993	0.987 ∼ 1.000	0.040
Hemoglobin	−0.012	0.005	5.594	0.988	0.979 ∼ 0.998	0.018

CI-AKI: contrast-induced acute kidney injury; CKD: chronic kidney disease; ARB: Angiotensin receptor blocker; NLR: Neutrophil-to-lymphocyte ratio; GFR estimated glomerular filtration rate.

Table 4. The best performance of five ML models for the prediction of CI-AKI.

Model	Accuracy	AUC	Recall	Precision	F1
LR	0.753	0.755	0.694	0.140	0.233
NB	0.762	0.774	0.611	0.132	0.217
RF	0.946	0.745	0.028	0.500	0.053
GDBT	0.940	0.755	0.139	0.357	0.200
XGBoost	0.907	0.718	0.167	0.158	0.162

Figure 3. Receiver operator characteristic curves(ROC) of the validation sets for the (a) GBDT model, (b) XGBoost model, (c) LR model, (d) RF model, and (e) NB model.