The Association Between the Neutrophil-to-Lymphocyte Ratio and Mortality in Patients With Acute Respiratory Distress Syndrome: A Retrospective Cohort Study

Neutrophil-to-Lymphocyte Ratio: A Promising Predictor of Mortality in Patients With Acute Respiratory Distress Syndrome. A Retrospective Analysis of a Single Hospital Center

OBJECTIVES

To examine how the neutrophil-to-lymphocyte ratio (NLR) affects both short-term and long-term mortality in individuals with acute respiratory distress syndrome (ARDS).

DESIGN

A retrospective study.

SETTING

Critical care unit.

PARTICIPANTS

A total of 785 patients with ARDS.

INTERVENTIONS

There were three groups in the NLR study. A Cox proportional hazards regression model was used to calculate the hazard ratio (HR) between the NLR and 30-day, 90-day, and 1-year mortality.

MEASUREMENTS AND MAIN RESULTS

The 785 patients included 329 women (41.9%) and 456 men (58.1%), with a mean age of 63.4 ± 16.7 years and a mean NLR of 14.2 ± 9.8. The study population was divided into 3 groups based on NLR value. In the unadjusted model, compared to group 1 (NLR <6.0), group 2 (NLR 6.0-11.3) and group 3 (NLR >11.3) had HR values of 1.12 (95% confidence interval [CI], 0.83-1.52) and 2.39 (95% CI, 1.87-3.04), respectively, for 30-day all-cause mortality. This association remained significant after adjusting for potential confounding variables (HR, 1.54; 95% CI, 1.18-2.02), with a statistically significant trend (p = 0.0004) in group 3 (NLR >11.3). A similar effect was seen on both 90-day and 1-year all-cause mortality. The R2 value in a 2-piecewise linear regression was 1.25 (95% CI, 1.06-1.48; p < 0.0001) on the left side of the inflection point (NLR 17.1).

CONCLUSIONS

In this retrospective single-center study, the NLR was a potential predictor of both short- and long-term mortality in patients with ARDS and may aid risk stratification.

DECREASE IN THE PLATELET-TO-LYMPHOCYTE RATIO IN DAYS AFTER ADMISSION FOR SEPSIS CORRELATES WITH IN-HOSPITAL MORTALITY

ABSTRACT

Background: A previous study has linked an increase in platelet-to-lymphocyte ratio (PLR) to a poor prognosis; however, the relationship between early change in PLR and outcomes in sepsis patients is unclear. Methods : The Medical Information Mart for Intensive Care IV database was for this retrospective cohort analysis on patients meeting the Sepsis-3 criteria. All the patients meet the Sepsis-3 criteria. The platelet-to-lymphocyte ratio (PLR) was calculated by dividing the platelet count by the lymphocyte count. We collected all PLR measurements that were available within 3 days of admission for analysis of longitudinal changes over time. Multivariable logistic regression analysis was used to determine the relationship between the baseline PLR and in-hospital mortality. After correcting for possible confounders, the generalized additive mixed model was used to examine the trends in PLR over time among survivors and nonsurvivors. Results: Finally, 3,303 patients were enrolled, and both low and high PLR levels were significantly associated with higher in-hospital mortality in the multiple logistic regression analysis (tertile 1: odds ratio, 1.240; 95% confidence interval, 0.981-1.568 and tertile 3: odds ratio, 1.410; 95% confidence interval, 1.120-1.776, respectively). The generalized additive mixed model results revealed that the PLR of the nonsurvival group declined faster than that of the survival group within 3 days after intensive care unit admission. After controlling for confounders, the difference between the two groups steadily decreased and increased by an average of 37.38 daily. Conclusions : There was a U-shaped relationship between the baseline PLR and in-hospital mortality of sepsis patients, and there was a significant difference between the nonsurvival and survival groups in the change in PLR over time. The early decrease in PLR was related to an increase in in-hospital mortality.

Role of CD8+ T cell exhaustion in the progression and prognosis of acute respiratory distress syndrome induced by sepsis: a prospective observational study

Background

CD8⁺ T cells are important for protective immunity against intracellular pathogens. Excessive amounts of antigen and/or inflammatory signals often lead to the gradual deterioration of CD8⁺ T cell function, a state called “exhaustion”. However, the association between CD8⁺ T cell exhaustion and acute respiratory distress syndrome (ARDS) has not been studied. This study was conducted to elucidate how CD8⁺ T cells and inhibitory receptors were related to the clinical prognosis of ARDS.

Methods

A prospective observational study in an emergency department enrolled patients who were diagnosed with sepsis-associated ARDS according to the sepsis-3 criteria and Berlin definition. Peripheral blood samples were collected within 24 h post recruitment. CD8⁺ T cell count, proliferation ratio, cytokine secretion, and the expression of coinhibitory receptors were assayed.

Results

Sixty-two patients with ARDS met the inclusion criteria. CD8⁺ T cell counts and proliferation rates were dramatically decreased in non-surviving ARDS patients. Increasing programmed cell death 1 (PD-1) expression on the CD8⁺ T cell surface was seen in patients with worse organ function, while an increasing level of T cell immunoglobulin mucin-3 (Tim-3) was associated with a longer duration of the shock. Kaplan–Meier analysis showed that low CD8⁺ T cell percentages and increased inhibitory molecule expression were significantly associated with a worse survival rate.

Conclusions

CD8⁺ T cells and coinhibitory receptors are promising independent prognostic markers of sepsis-induced ARDS, and increased CD8⁺ T cell exhaustion is significantly correlated with poor prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-022-00733-2.

The effect of reparixin on survival in patients at high risk for in-hospital mortality: a meta-analysis of randomized trials

Introduction

A great number of anti-inflammatory drugs have been suggested in the treatment of SARS-CoV-2 infection. Reparixin, a non-competitive allosteric inhibitor of the CXCL8 (IL-8) receptors C-X-C chemokine receptor type 1 (CXCR1) and C-X-C chemokine receptor type 2 (CXCR2), has already been tried out as a treatment in different critical settings. Due to the contrasting existing literature, we decided to perform the present meta-analysis of randomized controlled trials (RCTs) to investigate the effect of the use of reparixin on survival in patients at high risk for in-hospital mortality.

Methods

We created a search strategy to include any human RCTs performed with reparixin utilization in patients at high risk for in-hospital mortality, excluding oncological patients. Two trained, independent authors searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) for appropriate studies. Furthermore, references of review articles and included RCTs were screened to identify more studies. No language restrictions were enforced. To assess the risk of bias of included trials, the Revised Cochrane risk-of-bias tool for randomized trials (RoB 2) was used.

Results

Overall, six studies were included and involved 406 patients (220 received reparixin and 186 received the comparator). The all-cause mortality in the reparixin group was significantly lower than that in the control group [5/220 (2.3%) in the reparixin group vs. 12/186 (6.5%) in the control group, odds ratio = 0.33 (95% confidence interval 0.12 to 0.96), p-value for effect 0.04, p for heterogeneity 0.20, I2 = 36%]. In addition, no difference in the rate of pneumonia, sepsis, or non-serious infections was shown between the two groups.

Conclusion

Our meta-analysis of randomized trials suggests that short-term inhibition of CXCL8 activity improved survival in patients at high risk for in-hospital mortality without increasing the risk of infection.

Meta-analysis registration

PROSPERO, identifier CRD42021254467.

The Neutrophil-to-Lymphocyte Ratio is Associated with the Requirement and the Duration of Invasive Mechanical Ventilation in Acute Respiratory Distress Syndrome Patients: A Retrospective Study

Background

Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality and most ARDS patients require ventilatory support. Applying appropriate ventilation strategies based on patients' individual situations has a direct impact upon patients' outcome. The neutrophil-to-lymphocyte ratio (NLR) has been shown to predict the early requirement of invasive mechanical ventilation (IMV) in patients with coronavirus disease 2019 (COVID-19). Our study aimed to investigate the relationship between baseline NLR and IMV in ARDS.

Methods

A retrospective study was performed on patients who were diagnosed with ARDS using the Berlin definition and admitted to the First Affiliated Hospital of Soochow University from 2017 to 2022. Clinical data within 24 h after the ARDS diagnosis were collected from the medical record system. Based on the ventilation strategies during hospitalization, patients were divided into three groups and their clinical characteristics were compared. Furthermore, logistic regression analysis was used to screen the independent risk factors for IMV. STROBE checklist was used for this manuscript.

Results

520 ARDS patients were included and the median NLR value in IMV group was significantly higher than that of other groups (P < 0.001). NLR was significantly associated with the requirement of IMV in ARDS patients (OR, 1.042; 95% CI, 1.025–1.060; P < 0.001), other independent risk factors included PaO₂/FiO₂, Hb, lactate, and use of vasoactive drugs (all P < 0.05). Moreover, we found that the duration of IMV was longer in patients with high NLR (8[IQR, 3–13], 10[IQR, 6–16], respectively, P=0.025).

Conclusions

Our results revealed that high baseline NLR level was significantly correlated with an increased risk of IMV in patients with ARDS. Furthermore, higher NLR was associated with prolonged duration of IMV in patients with ARDS.

A new biomarker in severe pneumonia associated with coronavirus disease 2019: hypoalbuminemia. A prospective study

BACKGROUND

Effective triage and early detection are very important for controlling and treating coronavirus disease 2019 (COVID-19). Thus, the relationships between hypoalbuminemia and other acute-phase reactants in such cases need to be evaluated.

OBJECTIVES

To investigate the importance of albumin levels in cases of severe pneumonia due to COVID-19.

DESIGN AND SETTING

Prospective study conducted in Ankara City Hospital (a stage 3 hospital), Turkey.

METHODS

Data from 122 patients diagnosed with pneumonia due to COVID-19 who were admitted to this hospital were analyzed statistically in comparison with date from 60 healthy controls. Three groups were established: healthy controls, intubated patients and non-intubated patients. Lung tomography scans from the patients were examined one-by-one. Real-time polymerase chain reaction (RT-PCR) test results were recorded.

RESULTS

Albumin levels were statistically significantly lower in the intubated and non-intubated groups than in the control group, in comparing the three groups (P < 0.01). The other acute-phase reactants, i.e. neutrophil-to-lymphocyte ratio and C-reactive protein levels, were significantly higher in the intubated and non-intubated groups than in the control group (P < 0.05). Albumin levels were also significantly lower in the intubated group than in the non-intubated group (P = 0.02). No differences were detected with regard to other parameters (P > 0.05).

CONCLUSIONS

Hypoalbuminemia may constitute a biomarker indicating the severity of pneumonia due to COVID-19.

An activation specific anti-Mac-1 designed ankyrin repeat protein improves survival in a mouse model of acute lung injury

The acute respiratory distress syndrome (ARDS) is a life-threatening clinical condition. The number of ARDS cases has risen dramatically recently but specific treatment options are limited. ARDS is associated with an overshooting inflammatory response and neutrophils play a central role in its pathogenesis. Neutrophils express the integrin Mac-1 on their surface which adopts a resting and activated conformation depending on leukocyte activation. The aim of this study was to investigate the anti-inflammatory effects of the unique activation-specific anti-Mac-1 DARPin 'F7' in a mouse model of ARDS. ARDS was induced by intratracheal lipopolysaccharide (LPS) instillation and the acute (day 1-4) and chronic phase (day 5-10) were studied. After expression and purification, F7, a control DARPin and PBS, were applied daily via the intraperitoneal route. Survival and weight loss were recorded. Histological analysis of lung sections, flow cytometric leukocyte analysis of blood and bronchioalveolar lavage (BALF) were performed. Moreover, protein concentration and cytokine levels were determined in the BALF. Treatment with F7 improved survival and reduced weight loss significantly compared to treatment with the control DARPin or PBS. Neutrophil count in the BALF and peripheral blood were significantly reduced in mice treated with F7. Histology revealed significantly reduced pulmonary inflammation in the F7 treated group. Treatment with DARPin F7 inhibited neutrophil accumulation, reduced signs of local and systemic inflammation and improved survival in a mouse model of ARDS. F7 may be a novel anti-inflammatory drug candidate for the treatment of severe ARDS.

Neutrophil dysfunction due to continuous mechanical shear exposure in mechanically assisted circulation in vitro

OBJECTIVE

Leukocytes play an important role in the body's immune system. The aim of this study was to assess alterations in neutrophil phenotype and function in pump-assisted circulation in vitro.

METHODS

Human blood was circulated for four hours in three circulatory flow loops with a CentriMag blood pump operated at a flow of 4.5 L/min at three rotational speeds (2100, 2800, and 4000 rpm), against three pressure heads (75, 150, and 350 mm Hg), respectively. Blood samples were collected hourly for analyses of neutrophil activation state (Mac-1, CD62L, CD162), neutrophil reactive oxygen species (ROS) production, apoptosis, and neutrophil phagocytosis.

RESULTS

Activated neutrophils indicated by both Mac-1 expression and decreased surface expression of CD62L and CD162 receptors increased with time in three loops. The highest level of neutrophil activation was observed in the loop with the highest rotational speed. Platelet-neutrophil aggregates (PNAs) progressively increased in two loops with lower rotational speeds. PNAs peaked at one hour after circulation and decreased subsequently in the loop with the highest rotational speed. Neutrophil ROS production dramatically increased at one hour after circulation and decreased subsequently in all three loops with similar levels and trends. Apoptotic neutrophils increased with time in all three loops. Neutrophil phagocytosis capacity in three loops initially elevated at one hour after circulation and decreased subsequently. Apoptosis and altered phagocytosis were dependent on rotational speed.

CONCLUSIONS

Our study revealed that the pump-assisted circulation induced neutrophil activation, apoptosis, and functional impairment. The alterations were strongly associated with pump operating condition and duration.

Prognostic biomarkers in predicting mortality in respiratory patients with ventilator-associated pneumonia

Background

Ventilator-associated pneumonia (VAP) is the most common nosocomial infection. Red cell distribution width (RDW) and neutrophil-lymphocyte ratio (NLR) are prognostic factors to mortality in different diseases. The aim of this study is to evaluate prognostic efficiency RDW, NLR, and the Sequential Organ Failure Assessment (SOFA) score for mortality prediction in respiratory patients with VAP.

Results

One hundred thirty-six patients mechanically ventilated and developed VAP were included. Clinical characteristics and SOFA score on the day of admission and at diagnosis of VAP, RDW, and NLR were assessed and correlated to mortality. The average age of patients was 58.80 ± 10.53. These variables had a good diagnostic performance for mortality prediction AUC 0.811 for SOFA at diagnosis of VAP, 0.777 for RDW, 0.728 for NLR, and 0.840 for combined of NLR and RDW. The combination of the three parameters demonstrated excellent diagnostic performance (AUC 0.889). A positive correlation was found between SOFA at diagnosis of VAP and RDW (r = 0.446, P < 0.000) and with NLR (r = 0.220, P < 0.010).

Conclusions

NLR and RDW are non-specific inflammatory markers that could be calculated quickly and easily via routine hemogram examination. These markers have comparable prognostic accuracy to severity scores. Consequently, RDW and NLR are simple, yet promising markers for ICU physicians in monitoring the clinical course, assessment of organ dysfunction, and predicting mortality in mechanically ventilated patients. Therefore, this study recommends the use of blood biomarkers with the one of the simplest ICU score (SOFA score) in the rapid diagnosis of critical patients as a daily works in ICU.

Retrospective Study of Critically Ill COVID-19 Patients With and Without Extracorporeal Membrane Oxygenation Support in Wuhan, China

Background: Extracorporeal membrane oxygenation (ECMO) might benefit critically ill COVID-19 patients. But the considerations besides indications guiding ECMO initiation under extreme pressure during the COVID-19 epidemic was not clear. We aimed to analyze the clinical characteristics and in-hospital mortality of severe critically ill COVID-19 patients supported with ECMO and without ECMO, exploring potential parameters for guiding the initiation during the COVID-19 epidemic.

Methods: Observational cohort study of all the critically ill patients indicated for ECMO support from January 1 to May 1, 2020, in all 62 authorized hospitals in Wuhan, China.

Results: Among the 168 patients enrolled, 74 patients actually received ECMO support and 94 not were analyzed. The in-hospital mortality of the ECMO supported patients was significantly lower than non-ECMO ones (71.6 vs. 85.1%, P = 0.033), but the role of ECMO was affected by patients' age (Logistic regression OR 0.62, P = 0.24). As for the ECMO patients, the median age was 58 (47–66) years old and 62.2% (46/74) were male. The 28-day, 60-day, and 90-day mortality of these ECMO supported patients were 32.4, 68.9, and 74.3% respectively. Patients survived to discharge were younger (49 vs. 62 years, P = 0.042), demonstrated higher lymphocyte count (886 vs. 638 cells/uL, P = 0.022), and better CO₂ removal (PaCO2 immediately after ECMO initiation 39.7 vs. 46.9 mmHg, P = 0.041). Age was an independent risk factor for in-hospital mortality of the ECMO supported patients, and a cutoff age of 51 years enabled prediction of in-hospital mortality with a sensitivity of 84.3% and specificity of 55%. The surviving ECMO supported patients had longer ICU and hospital stays (26 vs. 18 days, P = 0.018; 49 vs. 29 days, P = 0.001 respectively), and ECMO procedure was widely carried out after the supplement of medical resources after February 15 (67.6%, 50/74).

Conclusions: ECMO might be a benefit for severe critically ill COVID-19 patients at the early stage of epidemic, although the in-hospital mortality was still high. To initiate ECMO therapy under tremendous pressure, patients' age, lymphocyte count, and adequacy of medical resources should be fully considered.

Early Alterations of Lymphocyte Subsets in Acute Respiratory Distress Syndrome Caused by Acinetobacter baumannii Pneumonia: A Prospective Observational Study

Background: To prospectively observe the early alterations of lymphocyte subsets in ARDS caused by Acinetobacter baumannii.

Methods: ARDS patients admitted to our ICU between January 1, 2017 and May 30, 2020 were selected. We enrolled all the pulmonary ARDS caused by Acinetobacter baumannii pneumonia who required mechanical ventilation or vasopressors. All the available clinical data, follow up information and lymphocyte subsets were recorded.

Results: Eighty-seven of all the 576 ARDS patients were enrolled. The 28-day mortality of the enrolled patients was 20.7% (18/87). The T lymphocyte count (452 vs. 729 cells/ul, P = 0.004), especially the CD8⁺ T lymphocyte count (104 vs. 253 cells/ul, P = 0.002) was significantly lower in non-survivors, as were counts of the activated T cell subsets (CD8⁺CD28⁺ and CD8⁺CD38⁺). The CD8⁺ T cell count was an independent risk factor for 28-day mortality, and a cutoff value of 123 cells/ul was a good indicator to predict the prognosis of ARDS caused by Acinetobacter baumannii pneumonia, with sensitivity of 74.6% and specificity of 83.3% (AUC 0.812, P < 0.0001).

Conclusions: Lower CD8⁺ T cell count was associated with higher severity and early mortality in ARDS patients caused by Acinetobacter baumannii pneumonia, which could be valuable for outcome prediction.

Marginating transitional B cells modulate neutrophils in the lung during inflammation and pneumonia

Pulmonary innate immunity is required for host defense; however, excessive neutrophil inflammation can cause life-threatening acute lung injury. B lymphocytes can be regulatory, yet little is known about peripheral transitional IgM+ B cells in terms of regulatory properties. Using single-cell RNA sequencing, we discovered eight IgM+ B cell subsets with unique gene regulatory networks in the lung circulation dominated by transitional type 1 B and type 2 B (T2B) cells. Lung intravital confocal microscopy revealed that T2B cells marginate in the pulmonary capillaries via CD49e and require CXCL13 and CXCR5. During lung inflammation, marginated T2B cells dampened excessive neutrophil vascular inflammation via the specialized proresolving molecule lipoxin A4 (LXA4). Exogenous CXCL13 dampened excessive neutrophilic inflammation by increasing marginated B cells, and LXA4 recapitulated neutrophil regulation in B cell-deficient mice during inflammation and fungal pneumonia. Thus, the lung microvasculature is enriched in multiple IgM+ B cell subsets with marginating capillary T2B cells that dampen neutrophil responses.

The Neutrophil/Lymphocyte Ratio Could Predict Noninvasive Mechanical Ventilation Failure in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Retrospective Observational Study

Purpose

To determine the effectiveness of neutrophil/lymphocyte ratio (NLR), compared to traditional inflammatory markers, for predicting noninvasive mechanical ventilation (NIMV) failure in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients.

Patients and Methods

We conducted this retrospective observational study including 212 AECOPD patients who required NIMV during hospitalization from January 2015 to December 2020 in the department of respiratory and critical care medicine of Beijing Chao-Yang Hospital (west campus). We reviewed the medical record to determine if NIMV succeeded or failed for each patient, and compared NLR with traditional markers (leukocyte, C-reactive protein [CRP] and procalcitonin [PCT]) between NIMV failure and NIMV success group. Receiver-operating characteristic (ROC) curve and multivariate logistic regression analysis were used to assess the accuracy of these markers for predicting NIMV failure.

Results

A total of 38 (17.9%) patients experienced NIMV failure. NLR was a more sensitive biomarker to predict NIMV failure (AUC, 0.858; 95% CI 0.785-0.931) than leukocyte counts (AUC, 0.723; 95% CI 0.623-0.823), CRP (AUC, 0.670; 95% CI 0.567-0.773) and PCT (AUC, 0.719; 95% CI 0.615-0.823). There was statistically positive correlation between NLR and leukocytes count (r=0.35, p<0.001), between NLR and CRP (r=0.258, p<0.001), between NLR and PCT (r=0.306, p<0.001). The cutoff value of NLR to predict NIMV failure was 8.9 with sensitivity 0.688, specificity 0.886 and diagnostic accuracy 0.868. NLR>8.9 (odds ratio, 10.783; 95% CI, 2.069-56.194; P=0.05) was an independent predictor of NIMV failure in the multivariate logistic regression model.

Conclusion

NLR may be an effective marker for predicting NIMV failure in AECOPD patients, and the patients with NLR>8.9 should be handled with caution since they are at higher risk of NIMV failure and require intubation. Further study with a larger sample size and with more data is necessary to confirm our study.

The neutrophil to lymphocyte ratio is an independent predictor for severe COVID-19 : Evidence from a multicenter case-control study and meta-analyses

Purpose

The aim of this study was to determine whether the neutrophil to lymphocyte ratio (NLR) can predict severe Coronavirus disease 2019 (COVID-19).

Patients and methods

A multicenter case-control study was conducted to investigate whether the NLR can help predict the severity of COVID-19. Patients confirmed to have COVID-19 between 16 January 2020 and 15 March 2020 were enrolled. Furthermore, meta-analyses were conducted based on both previous studies and our case-control study.

Results

In the case-control study, 213 patients (severe: 81) were included. The results suggested that the NLR was an independent risk factor (odds ratio [OR], 1.155, 95% confidence interval [95% CI]: 1.043–1.279, P = 0.006) and a great predictor (the area under the ROC curve was 0.728, 95% CI: 0.656–0.800) for severe COVID-19. In total, 18 datasets from 16 studies combined with our case-control study (severe: 1211; non-severe: 5838) were included in the meta-analyses and the results showed that the NLR of the severe COVID-19 group was significantly higher than that of the non-severe group (SMD = 1.10, 95% CI: 0.90–1.31, P < 0.001). Based on the 2 × 2 data from 6 studies, the SROC of NLR for predicting severe COVID-19 was 0.802, with a sensitivity of 0.67 (95% CI: 0.61–0.72) and a specificity of 0.75 (95% CI: 0.73–0.78).

Conclusion

Based on a multicenter case-control study and a meta-analysis, we found that the initial NLR was a great predictor of severe COVID-19.

Supplementary Information

The online version of this article (10.1007/s00508-021-01917-9) contains supplementary material, which is available to authorized users.

The Association Between the Baseline and the Change in Neutrophil-to-Lymphocyte Ratio and Short-Term Mortality in Patients With Acute Respiratory Distress Syndrome

Background: Two previous studies have shown that increased neutrophil to lymphocyte ratio (NLR) is associated with short-term prognosis in patients with acute respiratory distress syndrome (ARDS), but it is usually assessed as a single threshold value at baseline. We investigated the relationship between the baseline and the early change in NLR and 30-day mortality in patients with ARDS to evaluate the prognostic value of NLR baseline and NLR changes during the first 7 days after ICU admission. Methods: This is a retrospective cohort study, with all ARDS patients diagnosed according to the Berlin definition from the Medical Information Mart for Intensive Care III (MIMIC-III) database. We calculated the NLR by dividing the neutrophil count by the lymphocyte count. The multivariable logistic regression analysis was used to investigate the relationship between the baseline NLR and short-term mortality. Then the generalized additive mixed model was used to compare trends in NLR over time among survivors and non-survivors after adjusting for potential confounders. Results: A total of 1164 patients were enrolled in our study. Multivariable logistic regression analysis showed that after adjusting for confounders, elevated baseline NLR was a significant risk factor predicting 30-day mortality (OR 1.02, 95%CI 1.01, 1.03, P = 0.0046) and hospital mortality (OR 1.02, 95%CI 1.01, 1.03, P = 0.0003). The result of the generalized additive mixed model showed that the NLR decreased in the survival group and increased in the non-survival group gradually within 7 days after ICU admission. The difference between the two groups showed a trend of increase gradually and the difference increased by an average of 0.67 daily after adjusting for confounders. Conclusions: We confirmed that there was a positive correlation between baseline NLR and short-term mortality, and we found significant differences in NLR changes over time between the non-survival group and the survival group. The early increase in NLR was associated with short-term mortality in ARDS patients.

Prognostic Value of Inflammatory Biomarkers in 5-Year Survival After Endovascular Repair of Abdominal Aortic Aneurysms in a Predominantly Male Cohort: Implications for Practice

BACKGROUND

Prognostic factors of long-term survival can guide selection of patients for endovascular repair of abdominal aortic aneurysms (EVAR). The aim of this study was to evaluate the relationship between the neutrophil-to-lymphocyte ratio (NLR), the platelet-to-lymphocyte ratio (PLR), the lymphocyte-to-monocyte ratio (LMR) and the systemic immune-inflammation index (SIII) with survival after EVAR and to assess whether the addition of these biomarkers improved the prediction of survival after surgery.

METHODS

Retrospective analysis of 284 consecutive patients who underwent an EVAR at a single institution. The association between biomarkers and survival was explored using generalized additive models with penalized smoothing splines and multivariate Cox models. C-statistics and continuous net reclassification indexes (c-NRI) were used to assess the improvement in prediction.

RESULTS

Survival rates at 2 and 5 years were 83.9% and 66.2%, respectively. The predictive score of survival included hemoglobin (HR = 0.849, p = 0.004), statin intake (HR = 0.538, p = 0.004), atrial fibrillation (HR = 2.515, p < 0.001), heart failure (HR = 2.542, p = 0.017) and the non-revascularized coronary artery disease (HR = 2.163, p = 0.004). Spline analyses showed a linear relationship between survival and NLR, PLR, LMR and SII. After adjusting for the predictive score, there was an independent relationship between survival and NLR (HR = 1.072, p = 0.006), PLR (HR = 1.002, p = 0.014) and SII (HR = 1.000, p = 0.043). However, only the addition of NLR improved moderately the c-NRI. A NLR ≥ 3 was independently associated with lower survival rates at 2-years (HR 1.98; 95% CI 1.07-3.66) and 5-years (HR 1.84, 95% CI 1.22-2.78) of follow-up.

CONCLUSIONS

Most inflammatory biomarkers are linear and independently associated with survival after EVAR, but only the NLR improved moderately the prediction of a survival score. Therefore, a NLR ≥ 3 may be used to identify patients with a low survival rate and help in decision-making.

Current Understanding of Leukocyte Phenotypic and Functional Modulation During Extracorporeal Membrane Oxygenation: A Narrative Review

A plethora of leukocyte modulations have been reported in critically ill patients. Critical illnesses such as acute respiratory distress syndrome and cardiogenic shock, which potentially require extracorporeal membrane oxygenation (ECMO) support, are associated with changes in leukocyte numbers, phenotype, and functions. The changes observed in these illnesses could be compounded by exposure of blood to the non-endothelialized surfaces and non-physiological conditions of ECMO. This can result in further leukocyte activation, increased platelet-leukocyte interplay, pro-inflammatory and pro-coagulant state, alongside features of immunosuppression. However, the effects of ECMO on leukocytes, in particular their phenotypic and functional signatures, remain largely overlooked, including whether these changes have attributable mortality and morbidity. The aim of our narrative review is to highlight the importance of studying leukocyte signatures to better understand the development of complications associated with ECMO. Increased knowledge and appreciation of their probable role in ECMO-related adverse events may assist in guiding the design and establishment of targeted preventative actions.

Novel Perspectives Regarding the Pathology, Inflammation, and Biomarkers of Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is an acute inflammation of the lung resulting from damage to the alveolar-capillary membrane, and it is diagnosed using a combination of clinical and physiological variables. ARDS develops in approximately 10% of hospitalised patients with pneumonia and has a mortality rate of approximately 40%. Recent research has identified several biomarkers associated with ARDS pathophysiology, and these may be useful for diagnosing and monitoring ARDS. They may also highlight potential therapeutic targets. This review summarises our current understanding of those clinical biomarkers: (1) biomarkers of alveolar and bronchiolar injury, (2) biomarkers of endothelial damage and coagulation, and (3) biomarkers for treatment responses.

Prognostic value of neutrophil/lymphocyte ratio and mean platelet volume/platelet ratio for 1-year mortality in critically ill patients

Several studies have reported that the neutrophil to lymphocyte ratio (NLR) and mean platelet volume (MPV) are associated with poor prognosis. This study investigated whether NLR and/or the MPV/platelet ratio could function as predictive markers of mortality in critically ill patients. We retrospectively reviewed 1,154 patients admitted to the intensive care unit (ICU) between January 2017 and December 2017. Patients were divided into 2 groups according to 1-year mortality. We compared the NLR and MPV/platelet ratio on each day of ICU admission. Patients were classified into tertiles based on their NLR and MPV/platelet ratios, and the incidence of 1-year mortality was compared. Kaplan-Meier survival curves were plotted to evaluate their potential as prognostic factors for 1-year mortality. The NLR and MPV/platelet ratio were higher in the non-survivor group than in the survivor group. The incidence of 1-year mortality was the highest in the third tertile for both the NLR and MPV/platelet ratio. The MPV/platelet ratio was an independent predictor for 1-year mortality based on the Kaplan-Meier survival analysis. Our data showed that the MPV/platelet ratio is a predictive factor for 1-year mortality in critically ill patients.

Neutrophil-to-Lymphocyte Ratio and Outcomes in Louisiana COVID-19 Patients

BACKGROUND

Due to the rapidly escalating number of cases and the low baseline of overall health in Louisiana, we sought to determine the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) in hospitalized COVID patients in two major metropolitan areas with the highest prevalence of cases and exceedingly high rates of obesity and other comorbid conditions. We hypothesized that elevated NLR would be a prognostic indicator of mortality.

METHODS

This was a review of a prospective registry of adult (18+ years) hospitalized Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) patients from two large urban safety net hospitals in Louisiana. Blood cell counts at days 2 and 5 were used to obtain NLR. Receiver operating characteristic curve analysis assessed predictive capacity of NLR on mortality. Kaplan-Meier survival analysis and Cox regression models examined the effect of NLR on survival.

RESULTS

The study population of 125 patients was majority African American (88.6%) and female (54.8%) with a mean age and body mass index of 58.7 years and 34.2. Most (96.0%) had comorbidities of which hypertension (72.0%), obesity (66.7%), and diabetes (40.0%) were the most common. Mortality was 18.4%. NLR > 4.94 on day 1 predicted intubation (P = 0.02). NLR above established cutoff values on hospital days 2 and 5 each significantly predicted mortality (P < 0.001 and P = 0.002, respectively).

CONCLUSIONS

NLR is a prognostic factor for endotracheal intubation upon hospital admission and independent predictor for risk of mortality in SARS-CoV-2 patients on subsequent hospital days. Clinical research efforts should examine effects of strategies such as arginase inhibition alone and/or inhaled nitric oxide to ameliorate the effects of elevated NLR.

Inflammation, Thrombosis, and Destruction: The Three-Headed Cerberus of Trauma- and SARS-CoV-2-Induced ARDS

Physical trauma can be considered an unrecognized “pandemic” because it can occur anywhere and affect anyone and represents a global burden. Following severe tissue trauma, patients frequently develop acute lung injury (ALI) and/or acute respiratory distress syndrome (ARDS) despite modern surgical and intensive care concepts. The underlying complex pathophysiology of life-threatening ALI/ARDS has been intensively studied in experimental and clinical settings. However, currently, the coronavirus family has become the focus of ALI/ARDS research because it represents an emerging global public health threat. The clinical presentation of the infection is highly heterogeneous, varying from a lack of symptoms to multiple organ dysfunction and mortality. In a particular subset of patients, the primary infection progresses rapidly to ALI and ARDS. The pathophysiological mechanisms triggering and driving severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced ALI/ARDS are still poorly understood. Although it is also generally unknown whether insights from trauma-induced ARDS may be readily translated to SARS-CoV-2-associated ARDS, it was still recommended to treat coronavirus-positive patients with ALI/ARDS with standard protocols for ALI/ARDS. However, this strategy was questioned by clinical scientists, because it was documented that some severely hypoxic SARS-CoV-2-infected patients exhibited a normal respiratory system compliance, a phenomenon rarely observed in ARDS patients with another underlying etiology. Therefore, coronavirus-induced ARDS was defined as a specific ARDS phenotype, which accordingly requires an adjusted therapeutic approach. These suggestions reflect previous attempts of classifying ARDS into different phenotypes that might overall facilitate ARDS diagnosis and treatment. Based on the clinical data from ARDS patients, two major phenotypes have been proposed: hyper- and hypo-inflammatory. Here, we provide a comparative review of the pathophysiological pathway of trauma-/hemorrhagic shock-induced ARDS and coronavirus-induced ARDS, with an emphasis on the crucial key points in the pathogenesis of both these ARDS forms. Therefore, the manifold available data on trauma-/hemorrhagic shock-induced ARDS may help to better understand coronavirus-induced ARDS.

Associations of procalcitonin, C-reaction protein and neutrophil-to-lymphocyte ratio with mortality in hospitalized COVID-19 patients in China

Coronavirus disease 2019 (COVID-19) is an important and urgent threat to global health. Inflammation factors are important for COVID-19 mortality, and we aim to explore whether the baseline levels of procalcitonin (PCT), C-reaction protein (CRP) and neutrophil-to-lymphocyte ratio (NLR) are associated with an increased risk of mortality in patients with COVID-19. A retrospective study was conducted and a total of 76 patients with confirmed COVID-19 were included between January 17, 2020 to March 2, 2020, of these cases, 17 patients were dead. After adjusting covariates, PCT (≥ 0.10 ng/mL) and CRP (≥ 52.14 mg/L) exhibited independent increasing risks of mortality were used hazard ratio (HR) of 52.68 (95% confidence interval [CI]: 1.77–1571.66) and 5.47 (95% CI: 1.04–28.72), respectively. However, NRL (≥ 3.59) was not found to be an independent risk factor for death in our study. Furthermore, the elevated PCT levels were still associated with increasing risk of mortality in the old age group (age ≥ 60 y), and in the critically severe and severe patients after adjustment for complications. Thu Baseline levels of PCT and CRP have been addressed as independent predictors of mortality in patients with COVID-19.

Neutrophil to CD4+ lymphocyte ratio as a potential biomarker in predicting virus negative conversion time in COVID-19

BACKGROUND

Since December 2019, novel coronavirus (SARS-CoV-2)-infected pneumonia (COVID-19) occurred in Wuhan, and rapidly spread throughout China. Our study aimed to evaluate the robustness of neutrophil to CD4+ lymphocyte ratio (NCD4LR) in predicting the negative conversion time (NCT) of SARS-CoV-2 in COVID-19 patients.

METHODS

Univariate and multivariate analysis were conducted to evaluate the independency of NCD4LR in predicting NCT. Receiver operating characteristic (ROC) curve analysis and area under the curve (AUC) were used to assess the diagnostic accuracy.

RESULTS

Compared with low NCD4LR patients, patients with high NCD4LR had an older age; higher incidence of fever, fatigue, chest distress/breath shortness, severer disease assessment on admission; higher levels of inflammatory indicators; low levels of lymphocyte subsets, and a longer NCT. Multivariate analysis also identified NCD4LR as an independent risk factor for delayed NCT. ROC analysis showed that NCD4LR had a better performance than neutrophil to lymphocyte ratio in predicting the virus negative conversion within 2 weeks (AUC = 0.772), 3 weeks (AUC = 0.710), 4 weeks (AUC = 0.728), or 5 weeks (AUC = 0.815).

CONCLUSION

This study suggests that NCD4LR is a potential and useful biomarker for predicting the virus negative conversion time in COVID-19 patients. Furthermore, due to the NCDLR value is easily calculated, it can be widely used as a clinical biomarker for disease progression and clinical outcomes in COVID-19 patients.

A systematic review of biomarkers multivariately associated with acute respiratory distress syndrome development and mortality

Background

Heterogeneity of acute respiratory distress syndrome (ARDS) could be reduced by identification of biomarker-based phenotypes. The set of ARDS biomarkers to prospectively define these phenotypes remains to be established.

Objective

To provide an overview of the biomarkers that were multivariately associated with ARDS development or mortality.

Data sources

We performed a systematic search in Embase, MEDLINE, Web of Science, Cochrane CENTRAL, and Google Scholar from inception until 6 March 2020.

Study selection

Studies assessing biomarkers for ARDS development in critically ill patients at risk for ARDS and mortality due to ARDS adjusted in multivariate analyses were included.

Data extraction and synthesis

We included 35 studies for ARDS development (10,667 patients at risk for ARDS) and 53 for ARDS mortality (15,344 patients with ARDS). These studies were too heterogeneous to be used in a meta-analysis, as time until outcome and the variables used in the multivariate analyses varied widely between studies. After qualitative inspection, high plasma levels of angiopoeitin-2 and receptor for advanced glycation end products (RAGE) were associated with an increased risk of ARDS development. None of the biomarkers (plasma angiopoeitin-2, C-reactive protein, interleukin-8, RAGE, surfactant protein D, and Von Willebrand factor) was clearly associated with mortality.

Conclusions

Biomarker data reporting and variables used in multivariate analyses differed greatly between studies. Angiopoeitin-2 and RAGE in plasma were positively associated with increased risk of ARDS development. None of the biomarkers independently predicted mortality. Therefore, we suggested to structurally investigate a combination of biomarkers and clinical parameters in order to find more homogeneous ARDS phenotypes.

PROSPERO identifier

PROSPERO, CRD42017078957

Serum ammonia levels on admission for predicting sepsis patient mortality at D28 in the emergency department: A 2-center retrospective study

We assessed the predictive value of serum ammonia level on admission for the 28-day mortality of patients with sepsis.We retrospectively included septic patients admitted to the emergency department of West China Hospital, Sichuan University and The Fourth People's Hospital of Zigong city from June 2017 to May 2018. Patients were divided into 2 groups according to 28-day survival. Comparisons of serum ammonia level and sequential organ failure assessment (SOFA) score were made between 2 groups. Multivariate logistic regression models were employed to determine independent risk factors affecting 28-day mortality rate, and receiver operating characteristic (ROC) curve was also used to evaluate the efficacy of risk factors.Total of 316 patients were included into the study, 221 survived to 28 days and 95 were died before 28 days. The 28-day mortality rate was 30.06%. Multivariate logistic regression analyses revealed that the ammonia level, C reactive protein, SOFA score, and the leukocyte were independent risk factors for the 28-day mortality rate. In predicting the 28-day mortality rate, the SOFA score presented an area under the ROC curve (AUC) of 0.815, and the ammonia levels presented the AUC of 0.813.The ammonia level, C reactive protein, SOFA score, and the leukocyte are independent risk factors for 28-day mortality rate in septic patients. Moreover, the serum ammonia and SOFA score have similar predictive values. The serum ammonia level is also a suitable early indicator for prognostic evaluation of patients with sepsis as well.

Neutrophil-lymphocyte ratio as an early new marker in AIV-H7N9-infected patients: a retrospective study

Background: Avian AIV-H7N9 influenza progresses rapidly and has a high fatality rate. However, it lacks an early effective biomarker to predict disease severity and fatal outcomes successfully. Our study aimed to explore whether the neutrophil-to-lymphocyte ratio (NLR) taken within 24 h after admission can predict disease severity and fatality in AIV-H7N9-infected patients.

Methods: We retrospectively studied 237 AIV-H7N9-infected patients from multiple centers from 2013 to 2015. We used univariate analysis and multivariate analysis to compare clinical variables between the survival and fatal groups to evaluate the prognostic value.

Results: The NLR taken within 24 h after admission in the fatal group was significantly higher than that in the survival group (P<0.01). Our study found that NLR was independently associated with fatality. The area under the curve (AUC) of the NLR was 0.70, and moreover, when the NLR =19.94, the specificity was 100%, and the sensitivity was 28.4%. The fatality in the NLR ≥19.94 group was significantly increased relative to the patients with an NLR <19.94 (P<0.05).

Conclusion: The NLR is potentially a predictive prognostic biomarker in patients infected with the AIV-H7N9 influenza virus.

Association between Neutrophil-to-Lymphocyte Ratio and Gut Microbiota in a Large Population: a Retrospective Cross-Sectional Study

Gut microbiota and blood neutrophil-to-lymphocyte ratio (NLR) are associated with systemic inflammation; however, data on the association between gut microbiota and NLR are lacking. We investigated the association between gut microbiota and NLR. A total of 1,309 subjects who had available data on NLR and 16 S rRNA sequencing of gut microbiota were included in this study. They were grouped according to NLR quartile (Q) as follows: lower Q (n = 328, <25% of NLR range), middle 2Q (n = 653, ≥25% to <75%) and upper Q (n = 328, ≥75%). The diversity and composition of the human gut microbiota in the groups were calculated. The phylogenetic diversity of gut microbiota in the lower group was significantly higher than in the middle 2Q group (P = 0.040). The beta-diversity was significantly different among the three groups (P = 0.043), between the lower and middle 2Q groups (P = 0.029), and between the lower and upper groups (P = 0.026). Bacteroides eggerthii showed a positive correlation with NLR (q = 0.015). The diversity and composition of the gut microbiome were different between the NLR groups. Particularly, patients with a lower NLR had a greater diversity of gut microbiota.