Validation of Neutrophil-to-Lymphocyte Ratio Cut-off Value Associated with High In-Hospital Mortality in COVID-19 Patients

Figures & data

Table 1 Clinical Characteristics of Patients with COVID-19

Characteristics	Derivation Cohort (N=198)	Validation Cohort (N=101)	P value
Sexe (Male)	110 (55%)	65 (64%)	0.14
Mean Age	64.4 [14]	62.3 [17.2]	0.269
BMI (kg/m^2)	28 [5]	27 [5]	0.444
Smoking	8 (4%)	2 (2%)	0.35
Mean SpO2*	90% [4.6]	89% [4.5]	0.004
Nbr of patients with OT	179 (91%)	99 (98%)	0.02
Mechanical and non-mechanical respiratory support
HFNC	29 (15%)	16 (15.8%)	0.78
Oxygen mask	87 (44%)	55 (54.5%)	0.09
CPAP	56 (28%)	43 (42%)	0.13
Invasive mechanical ventilation	18 (9%)	8 (7.9%)	0.73
Co-morbidities
Cardiovascular disease	107 (54%)	45 (44.6%)	0.12
Hypertension	101 (51%)	52 (51.5%)	0.94
Chronic pulmonary disease	33 (17%)	10 (9.9%)	0.11
Diabetes	49 (25%)	22 (21.8%)	0.6
Immunosuppression	24 (12%)	18 (17.8%)	0.18
Chronic liver disease	10 (5%)	2 (2%)	0.2
Chronic kidney disease	36 (18%)	16 (15.8%)	0.54
Malignancy	10 (5%)	6 (5.9%)	0.75
Biological data
CRP on admission (mg/dl)	103.4 [81.7]	100 [74.8]	0.735
WBC count on admission	6.7 [3.3]	7 [3.7]	0.431
Absolute Neutrophil Count on admission (x10 ^3/mm^3)	5.13 [2.99]	5.5 [3.3]	0.398
NLR on admission	7 [7.4]	7.3 [6.1]	0.767
Eosinophil count on admission (x10 ^3/mm^3)	0.02 (0.04)	0.02 (0.05)	0.930
LDH (UI/L)	385 [189]	369 [136]	0.445
AST (UI/L)	54 [81]	43 [26]	0.195
ALT (UI/L)	39 [74]	36 [31]	0.696
D-Dimer (ng/mL)	2634 [4077]	1926 [3349]	0.177
Creatinine (mg/dl)	1.4 [1.6]	1.4 [3]	0.867
Troponin T (ng/L)	31.2 [69.1]	15.2 [19.2]
Lung CT scan	188 (95%)	80 (79.2%)	0.001
Stratification of lung lesions on CT scan
<10%	15 (7.6%)	7 (6.9%)	0.2
10–25%	90 (45.5%)	28 (27.7%)
25–50%	53 (26.8%)	25 (24.8%)
>50%	30 (15.2%)	20 (19.8%)
Outcome
Overall death	29 (15%)	19 (18.8%)	0.35
ICU admission	37 (19%)	16 (15.8%)	0.54
Death in ICU	11 (6%)	6 (5.9%)	0.9
Treatment
HCQ	144 (72.7%)	/
HCQ with AZT	18 (9.1%)	/
HCQ combined with CS	19 (9.6%)	/
HCQ with AZT and CS	17 (8.6%)	/
Dexamethasone	/	101 (100%)

Notes: *When breathing ambient air. Data are mean (SD), Interquartile range [IQR] or percentage (%).

Abbreviations: OT, oxygen therapy; HCQ, hydroxychloroquine; AZT, azithromycin; CS, corticosteroids; HFNC, high Flow Nasal Cannula; NLR, neutrophil to lymphocyte ratio; CPAP, continuous positive airway pressure; CRP, C-reactive protein, ICU: intensive care unit.

Table 2 Overall Death According to Different NLR Cut-off Value in the Validation Cohort and Evaluation by Net Reclassification Improvement

NLR	Death	Alive	p value	NRI
NLR <5.94	6 (32%)	53 (65%)	0.008	0.012 (p value =0.31)
NLR >5.94	13 (68%)	29 (35%)
NLR <6.4	6 (32%)	54 (67%)	0.006
NLR >6.4	13 (68%)	28 (34%)

Abbreviations: NRI, net reclassification improvement; NLR, neutrophil to lymphocyte ratio.

Figure 1 Receiver-operating characteristic (ROC) curves showing the discrimination performance of NLR cut off values in the derivation (1A) and validation (1B) cohort.