Value of Laboratory Indicators in Predicting Pneumonia in Symptomatic COVID-19 Patients Infected with the SARS-CoV-2 Omicron Variant

Figures & data

Figure 1 The flowchart of patients according to inclusion and exclusion criteria.

Table 1 Clinical Characteristics of Symptomatic COVID-19 Patients Infected by SARS-CoV-2 Omicron Variant

Variables	Total (n=144)	Non-Pneumonia (n=94)	Pneumonia (n=50)	P value
Age, years	66(51, 74)	66(50,73)	69(53,76)	0.481
Male	79(54.9%)	49(52.1%)	30(60.0%)	0.366
Hypertension	51(35.4%)	36(38.3%)	15(30.0%)	0.322
Diabetes	24(16.7%)	19(20.2%)	5(10.0%)	0.117
Cardiovascular diseases	6(4.2%)	4(4.3%)	2(4.0%)	1.000
Chronic respiratory diseases	4(2.8%)	1(1.1%)	3(6.0%)	0.121
Chronic kidney disease	9(6.3%)	6(6.4%)	3(6.0%)	1.000
Vaccination				0.140
0 dose	64(44.4%)	38(40.4%)	26(52.0%)
1 dose	4(2.8%)	3(3.2%)	1(2.0%)
2 doses	34(23.6%)	22(23.4%)	12(24.0%)
3 doses	42(29.2%)	31(33.0%)	11(22.0%)
NCT, days	8(5,10)	7(5,10)	9(5,13)	0.040

Note: Data are presented as median (Quartile 25th–75th) for continuous variables and as number with percentage for categorical variables.

Abbreviation: NCT, negative conversion time.

Figure 2 CT images in pneumonia COVID-19 patients infected by SARS-CoV-2 Omicron variant. (A–C), peripheral ground glass lesions. (D and E), scattered ground-glass lesions in both lungs. (F and G), local consolidation.(H and I), diffuse ground glass lesions in both lungs.

Table 2 Laboratory Findings of Symptomatic COVID-19 Patients Infected by SARS-CoV-2 Omicron Variant

Variables	Total (n=144)	Non-Pneumonia (n=94)	Pneumonia (n=50)	P value
Leukocytes, ×10^9/L	5.41(4.18,6.71)	5.23(4.02,6.48)	5.92(4.50,7.74)	0.043
Lymphocytes, ×10^9/L	1.45(1.06,1.91)	1.60(1.14,1.95)	1.25(0.87,1.77)	0.048
Neutrophils, ×10^9/L	3.16(2.28,4.50)	2.95(2.17,4.23)	3.68(2.77,5.13)	0.009
Monocytes, ×10^9/L	0.40(0.31,0.53)	0.40(0.30,0.49)	0.42(0.33,0.56)	0.136
Eosinophils, ×10^9/L	0.06(0.02,0.14)	0.07(0.03,0.14)	0.06(0.02,0.13)	0.424
Platelets, ×10^9/L	200(151,247)	199(157,249)	211(144,243)	0.985
Hemoglobin, g/L	132(116,141)	132(118,143)	131(114,140)	0.685
ALT, U/L	19.0(13.0,30.5)	19.0(12.8,28.3)	21.0(13.0,34.0)	0.281
AST, U/L	22.0(17.0,27.0)	21.0(17.8,26.0)	23.0(16.0,31.0)	0.522
Total Bilirubin, umol/L	8.0(6.4,12.4)	7.8(6.0,12.7)	8.3(6.8,11.9)	0.536
Direct bilirubin, umol/L	3.0(2.1,4.7)	2.9(2.0,4.8)	3.2(2.4,4.3)	0.498
Total protein, g/L	65.5(63.2,69.9)	65.4(62.4,70.6)	65.9(63.7,68.7)	0.993
Albumin, g/L	40.4(38.2,43.3)	40.4(37.8,43.3)	40.5(38.5,43.2)	0.575
Blood urea nitrogen, mmol/L	4.45(3.78,5.86)	4.51(3.78,5.90)	4.41(3.78,5.85)	0.939
Serum creatinine, umol/L	67.5(59.0,76.0)	69.0(59.0,77.3)	66.5(55.3,74.8)	0.310
Fibrinogen, g/L	3.21(2.76,4.00)	3.11(2.60,3.75)	3.68(2.82,4.45)	0.008
D-dimer, ug/mL	0.45(0.32,0.75)	0.45(0.33,0.76)	0.42(0.29,0.88)	0.374

Note: Data are presented as median (Quartile 25th–75th) for continuous variables.

Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase.

Table 3 Derived Hematological Indicators of Symptomatic COVID-19 Patients Infected by SARS-CoV-2 Omicron Variant

Variables	Total (n=144)	Non-Pneumonia (n=94)	Pneumonia (n=50)	P value
NLR	2.16(1.45,3.05)	2.00(1.26,2.86)	2.60(1.82,4.90)	0.001
MLR	0.27(0.20,0.44)	0.25(0.18,0.36)	0.35(0.22,0.52)	0.009
ELR	0.046(0.016,0.102)	0.046(0.016,0.083)	0.043(0.019,0.109)	0.613
PLR	144.11(104.89,174.90)	139.40(99.08,170.69)	150.32(120.96,218.89)	0.140
FLR	2.26(1.67,3.19)	2.07(1.60,2.91)	2.76(2.05,4.21)	0.001
FDR	7.18(4.54,10.11)	6.77(4.24,9.44)	9.24(5.0,12.30)	0.023

Note: Data are presented as median (Quartile 25th–75th) for continuous variables.

Abbreviations: NLR, neutrophil to lymphocyte ratio; MLR, monocyte to lymphocyte ratio; ELR, eosinophil to lymphocyte ratio; PLR, platelet to lymphocyte ratio; FLR, fibrinogen to lymphocyte ratio; FDR, fibrinogen to D-dimer ratio.

Table 4 The Area Under the ROC Curve and Optimal Cut-Off Values for the Blood Parameters Based on the Presence of Pneumonia in Symptomatic COVID-19 Patients Infected by SARS-CoV-2 Omicron Variant

Variables	AUC (95% CI)	P value	Cut-Off Level	Sensitivity	Specificity	Youden Index
Leukocytes	0.603(0.501–0.704)	0.043	≥6.345×10^9/L	46.0%	74.5%	0.205
Lymphocytes	0.615(0.517–0.712)	0.024	≤1.340×10^9/L	60.0%	63.8%	0.238
Neutrophils	0.632(0.534–0.730)	0.009	≥2.945×10^9/L	72.0%	50.0%	0.22
Monocytes	0.576(0.478–0.674)	0.136	≥0.525×10^9/L	36.0%	80.9%	0.169
Eosinophils	0.520(0.419–0.621)	0.696	≤0.075×10^9/L	60.0%	47.9%	0.079
Platelets	0.504(0.403–0.606)	0.935	≤150.5×10^9/L	30.0%	78.7%	0.087
Hemoglobin	0.528(0.427–0.628)	0.585	≤123.5g/L	40.0%	70.2%	0.102
Fibrinogen	0.635(0.539–0.730)	0.008	≥3.99g/L	40.0%	83.0%	0.230
D-dimer	0.455(0.348–0.562)	0.374	≥1.93ug/mL	14.0%	97.9%	0.119

Note: The optimal discriminating cut-off values were obtained by calculating the Youden index.

Abbreviations: AUC, area under the ROC curve; CI, confidence interval; ROC curve, receiver operating characteristic curve.

Figure 3 Receiver operating characteristic (ROC) curve for the blood parameters according to the presence of pneumonia in symptomatic COVID-19 patients infected by SARS-CoV-2 Omicron variant. (A), ROC curve for leukocytes, neutrophils, fibrinogen and D-dimer. (B), ROC curve for lymphocytes.

Table 5 The Area Under the ROC Curve and Optimal Cut-Off Values for the Derived Haematological Indicators Based on the Presence of Pneumonia in Symptomatic COVID-19 Patients Infected by SARS-CoV-2 Omicron Variant

Variables	AUC (95% CI)	P value	Cut-Off Level	Sensitivity	Specificity	Youden Index
NLR	0.670(0.580–0.760)	0.001	≥2.23	62.0%	62.8%	0.248
MLR	0.632(0.535–0.728)	0.009	≥0.34	54.0%	74.5%	0.285
ELR	0.526(0.424–0.627)	0.613	≥0.09	36.0%	78.7%	0.147
PLR	0.575(0.474–0.676)	0.140	≥268.24	22.0%	96.8%	0.188
FLR	0.669(0.575–0.763)	0.001	≥2.21	70.0%	57.4%	0.274
FDR	0.615(0.510–0.721)	0.023	≥10.43	40.0%	87.2%	0.272
NLR+FDR	0.701(0.606–0.796)	<0.001	–	56.0%	83.0%	–

Note: The optimal discriminating cut-off values were obtained by calculating the Youden index.

Abbreviations: AUC, area under the ROC curve; CI, confidence interval; ROC curve, receiver operating characteristic curve; NLR, neutrophil to lymphocyte ratio; MLR, monocyte to lymphocyte ratio; ELR, eosinophil to lymphocyte ratio; PLR, platelet to lymphocyte ratio; FLR, fibrinogen to lymphocyte ratio; FDR, fibrinogen to D-dimer ratio.

Figure 4 Receiver operating characteristic (ROC) curve for the derived hematological indicators according to the presence of pneumonia in symptomatic COVID-19 patients infected by SARS-CoV-2 Omicron variant. (A), ROC curve for NLR, MLR, FLR and FDR. (B), ROC curve for NLR+FDR.

Abbreviations: NLR, neutrophil to lymphocyte ratio; MLR, monocyte to lymphocyte ratio; FLR, fibrinogen to lymphocyte ratio; FDR, fibrinogen to D-dimer ratio.

Table 6 Univariate and Multivariate Logistic Analyses for Determining Risk Factors for Pneumonia in Symptomatic COVID-19 Patients Infected by SARS-CoV-2 Omicron Variant

Variables	Univariate Analysis			Multivariate Analysis
	B	OR(95% CI)	P value	B	OR(95% CI)	P value
NLR	0.198	1.219(95% CI:1.046–1.421)	0.011	0.222	1.248(95% CI:1.068–1.459)	0.005
MLR	1.356	3.880(95% CI:0.946–15.91)	0.06	–	–	–
ELR	0.876	2.402(95% CI:0.437–13.212)	0.314	–	–	–
PLR	0.003	1.003(95% CI:1.000–1.007)	0.056	–	–	–
FLR	0.157	1.170(95% CI:1.014–1.349)	0.031	–	–	–
FDR	0.123	1.131(95% CI:1.039–1.231)	0.005	0.148	1.160(95% CI:1.054–1.276)	0.002

Abbreviations: OR, odds ratio; CI, confidence interval; NLR, neutrophil to lymphocyte ratio; MLR, monocyte to lymphocyte ratio; ELR, eosinophil to lymphocyte ratio; PLR, platelet to lymphocyte ratio; FLR, fibrinogen to lymphocyte ratio; FDR, fibrinogen to D-dimer ratio.