Baseline Characteristics of the Study Population
In total, 5240 patients who met the selection criteria were enrolled in our study, among whom 43 patients (0.82%) died in the hospital. The baseline characteristics of the enrolled patients are summarized in the Table 1.
Table 1
Baseline characteristics of the study population with different survival status in hospital
|
Survivors
(n = 5197)
|
Nonsurvivors
(n = 43)
|
P value
|
Demographics
|
|
|
|
Age
|
0.00139 ± 0.00001
|
0.00150 ± 0.00011
|
0.311
|
Male, n (%)
|
2823 (53.87%)
|
26 (0.50%)
|
0.420
|
Birthweight (kg)
|
1.63 (1.10–2.48)
|
0.84 (0.62–1.59)
|
< 0.0001
|
Heart rate (bpm)
|
152 (140–169)
|
150 (140–168)
|
0.001
|
Laboratory events
|
|
|
|
RBC, 106/L
|
4.14 (3.70–4.62)
|
3.80 (3.45–4.23)
|
0.001
|
WBC, 109/L
|
15.3 (10.9–19.8)
|
8.8 (4.7–11.4)
|
< 0.0001
|
Lymphocytes, %
|
29 (21–42)
|
54.55 (33–67)
|
< 0.0001
|
Neutrophils, %
|
57 (42.9–66)
|
27 (19–46)
|
< 0.0001
|
Monocytes, %
|
7 (4-9.2)
|
7 (4–11)
|
0.707
|
Platelets, 109/L
|
284 (232–338)
|
212 (174–240)
|
< 0.0001
|
LMR
|
4.33 (2.75–7.4)
|
7.67 (4.17-13)
|
< 0.0001
|
NLR
|
2 (1.02–3.13)
|
0.55 (0.28–1.64)
|
0.0008
|
PLR
|
9.77 (6.15–14.36)
|
3.67 (2.73–5.72)
|
< 0.0001
|
Comorbidities
|
|
|
|
Congestive heart failure
|
14 (0.27%)
|
0 (0.00%)
|
0.736
|
Cardiac arrhythmias
|
19 (0.36%)
|
0 (0.00%)
|
0.694
|
Valvular disease
|
8 (0.15%)
|
0 (0.00%)
|
0.799
|
Pulmonary circulation disorder
|
5 (0.10%)
|
0 (0.00%)
|
0.840
|
Hypertension
|
10 (0.19%)
|
0 (0.00%)
|
0.773
|
Liver disease
|
2 (0.03%)
|
1 (0.015%)
|
< 0.0001
|
Renal failure
|
0 (0.00%)
|
1 (0.015%)
|
< 0.0001
|
Scores
|
|
|
|
SAPS II
|
18.86 ± 0.15
|
37.58 ± 0.81
|
< 0.0001
|
SOFA
|
2.75 ± 0.05
|
10.91 ± 0.41
|
< 0.0001
|
MELD
|
7.97 ± 0.05
|
11.64 ± 0.70
|
< 0.0001
|
Values are presented as the mean ± standard deviation, median (interquartile range), or number of patients (%).
WBC, white blood cell; SAPS II, Simplified Acute Physiology Score II; SOFA, Sequential Organ Failure Assessment; MELD, model for end-stage liver disease
|
The demographic characteristics of the survivors and nonsurvivors are presented in Table 1. No significant differences were observed for age and sex between nonsurvivors and survivors. Nonsurvivors had a higher birthweight and HR. Moreover, nonsurvivors had much higher RBCs, WBCs, neutrophils, platelets, NLRs and PLRs. Nonsurvivors tended to have lower lymphocytes, LMRs, SAPS II scores, SOFA scores and MELD scores, as well as a history of liver disease and renal failure (Table 1).
Association of Inflammatory Markers with Length of Hospital Stay and ICU Stay in Newborn Patients in the NICU
LMR, NLR and PLR were reported to be related to the outcome of various diseases. To investigate the associations of these inflammatory markers with the length of hospital stay and ICU stay in newborn patients in the NICU, Spearman’s rank correlation test was used, and the results are shown in Table 2. LMR was significantly positively associated with length of hospital stay and ICU stay (hospital stay: Spearman’s rho = 0.228, P < 0.0001; ICU stay: Spearman’s rho = 0.254, P < 0.0001). Both NLR and PLR were negatively associated with length of hospital stay and ICU stay (for NLR, hospital stay: Spearman’s rho=-0.427, P < 0.0001; ICU stay: Spearman’s rho=-0.448, P < 0.0001. For PLR, hospital stay: Spearman’s rho=-0.416, P < 0.0001; ICU stay: Spearman’s rho=-0.442, P < 0.0001).
Table 2
The correlation of LMR, NLR and PLR with hospital stay and ICU stay
|
Length of Hospital stay
|
|
Length of ICU stay
|
|
Spearman’s Rho
|
P value
|
|
Spearman’s Rho
|
P value
|
LMR
|
0.228
|
< 0.0001
|
|
0.254
|
< 0.0001
|
NLR
|
-0.427
|
< 0.0001
|
|
-0.448
|
< 0.0001
|
PLR
|
-0.416
|
< 0.0001
|
|
-0.442
|
< 0.0001
|
Association of Inflammatory Markers with Hospital Mortality in Newborn Patients in the NICU
In the present study, the correlation of the inflammatory markers with the mortality in the newborn patients in the NICU was investigated. Quartiles of LMR, NLR and PLR were significantly correlated with hospital mortality (all P < 0.0001) (Table 3). A higher rate of hospital mortality was observed in patients in the fourth LMR quartile than is those in the first, second and third quartiles. For NLR and PLR, a higher rate of hospital mortality was observed in patients in the first quartile than in those in other quartiles.
Table 3
The relationship between LMR, NLR and PLR with Hospital mortality
|
Q1
|
Q2
|
Q3
|
Q4
|
P value
|
LMR
|
|
|
|
|
|
Survivors
|
1364(26.03%)
|
1288(24.58%)
|
1288(24.58%)
|
1257(23.99%)
|
< 0.0001
|
Nonsurvivors
|
3(0.06%)
|
5(0.10%)
|
6(0.11%)
|
29(0.55%)
|
NLR
|
|
|
|
|
|
Survivors
|
1285(24.52%)
|
1277(24.37%)
|
1284(24.50%)
|
1351(25.78%)
|
< 0.0001
|
Nonsurvivors
|
31(0.59%)
|
4(0.076%)
|
4(0.076%)
|
4(0.076%)
|
PLR
|
|
|
|
|
|
Survivors
|
1258(24.01%)
|
1283(24.48%)
|
1288(24.58%)
|
1368(26.11%)
|
< 0.0001
|
Nonsurvivors
|
32(0.61%)
|
5(0.10%)
|
2(0.038%)
|
4(0.076%)
|
Q, Quartiles of LMR, NLR and PLR.
|
Prognostic Significance of PLR in Newborn Patients in the NICU
Univariate logistic regression analysis was performed. As shown in Table 4, PLR, NLR and LMR were associated with hospital mortality and 90-day mortality (PLR for hospital mortality: OR = 0.76, 95% CI = 0.69–0.83, P < 0.0001. NLR for hospital mortality: OR = 0.50, 95% CI = 0.37–0.69, P < 0.0001. LMR for hospital mortality: OR = 1.03, 95% CI = 1.01–1.05, P < 0.0001. PLR for 90-day mortality: OR = 0.76, 95% CI = 0.69–0.84, P < 0.0001. NLR for 90-day mortality: OR = 0.49, 95% CI = 0.36–0.68, P < 0.0001. LMR for 90-day mortality: OR = 1.04, 95% CI = 1.02–1.05, P < 0.0001).
Table 4
Univariate Logistic regression analyses for prognosis in newborn patients
Outcome
|
OR
|
95% CI
|
P value
|
Hospital mortality
|
PLR
|
0.76
|
0.69–0.83
|
< 0.0001
|
NLR
|
0.50
|
0.37–0.69
|
< 0.0001
|
LMR
|
1.03
|
1.01–1.05
|
< 0.0001
|
MELD
|
1.19
|
1.12–1.25
|
< 0.0001
|
SAPS II
|
1.17
|
1.13–1.21
|
< 0.0001
|
Liver disease
|
63.18
|
5.62-710.58
|
0.001
|
90-day mortality
|
PLR
|
0.76
|
0.69–0.84
|
< 0.0001
|
NLR
|
0.49
|
0.36–0.68
|
< 0.0001
|
LMR
|
1.04
|
1.02–1.05
|
< 0.0001
|
MELD
|
1.18
|
1.12–1.25
|
< 0.0001
|
SAPS II
|
1.17
|
1.13–1.22
|
< 0.0001
|
Liver disease
|
63.18
|
5.62-710.58
|
0.001
|
The results of the multivariate analysis are summarized in Table 5, and only PLR was significantly associated with hospital mortality (Model 1: OR = 0.85, 95% CI = 0.75–0.95, P = 0.005; Model 2: OR = 0.75, 95% CI = 0.67–0.84, P < 0.0001) and 90-day mortality (Model 1: OR = 0.85, 95% CI = 0.76–0.96, P = 0.010; Model 2: OR = 0.79, 95% CI = 0.71–0.89, P < 0.0001) in all models. In the multivariate analysis, Model 1 was adjusted for NLR, LMR, MELD, SAPS II and Liver disease. Model 2 was adjusted for NLR, LMR and Meld. The data suggested that PLR could be an independent risk factor for hospital mortality and 90-day mortality in the newborn patients in the NICU.
Table 5
Association between PLR with Prognosis of newborn patients
|
Model 1
|
Model 2
|
Variable
|
OR (95%CI)
|
P value
|
OR (95%CI)
|
P value
|
Hospital Mortality
|
PLR
|
0.84 (0.75–0.95)
|
0.005
|
0.75 (0.67–0.84)
|
< 0.0001
|
NLR
|
1.37 (0.98–1.90)
|
0.063
|
1.18 (0.85–1.65)
|
0.315
|
LMR
|
1.01 (0.99–1.03)
|
0.253
|
1.01 (0.99–1.03)
|
0.377
|
MELD
|
0.89 (0.80–0.99)
|
0.028
|
1.11 (1.05–1.19)
|
< 0.0001
|
SAPS II
|
1.19 (1.14–1.26)
|
< 0.0001
|
|
|
Liver disease
|
11.39 (0.84-154.04)
|
0.067
|
|
|
90-day Mortality
|
PLR
|
0.85 (0.76–0.96)
|
0.010
|
0.79 (0.71–0.89)
|
< 0.0001
|
NLR
|
1.32 (0.94–1.86)
|
0.106
|
1.15 (0.82–1.63)
|
0.417
|
LMR
|
1.01 (0.99–1.03)
|
0.182
|
1.01 (0.99–1.03)
|
0.232
|
MELD
|
0.88 (0.79–0.98)
|
0.017
|
1.12 (1.04–1.19)
|
0.001
|
SAPS II
|
1.20(1.14–1.27)
|
< 0.0001
|
|
|
Liver disease
|
11.53 (0.83-159.82)
|
0.068
|
|
|
Model 1 was adjusted for NLR, LMR, Meld, SAPS II and Liver disease.
Model 2 was adjusted for NLR, LMR and MELD.
|
Prognostic Predictive Ability of Models Combining PLR with Other Variables for Hospital Mortality in Newborn Patients in the NICU
To evaluate the predictive ability of models combining PLR and other clinical variables for hospital mortality, ROC curve analysis was performed, and the AUC for Model 1 (Model 1: PLR, LMR and NLR) was 0.804 (95% CI = 0.73–0.88, P < 0.0001) and for Model 2 (Model 2: PLR, LMR, NLR, SOFA and MELD) was 0.964 (95% CI = 0.95–0.98, P < 0.0001) (Fig. 1).