Blood Eosinophils and Outcomes in Severe Hospitalized Exacerbations of COPD

Corticosteroids in critically ill patients: A narrative review

Corticosteroids have been utilized in modern medicine for decades. Many indications have been investigated across various treatment settings with both benefit and harm observed. Given the instability of critically ill patients, the increased risk of corticosteroid-related complications, and the pervasive comorbidities, patients who receive corticosteroids must be carefully managed. Common critical care disease states in which corticosteroids have been studied and are routinely utilized include acute respiratory distress syndrome, adrenal insufficiency, angioedema, asthma, chronic obstructive pulmonary disease, community-acquired pneumonia, coronavirus disease 2019, septic shock, and spinal cord injury. Benefits of corticosteroids include an improvement in disease state-specific outcomes, decreased hospital length of stay, decreased mechanical ventilatory support, and decreased mortality. The harm of corticosteroids is well documented through adverse effects that include, but are not limited to, hyperglycemia, tachycardia, hypertension, agitation, delirium, anxiety, immunosuppression, gastrointestinal bleeding, fluid retention, and muscle weakness. Furthermore, corticosteroids are associated with increased health care costs through adverse effects as well as drug acquisition and administration costs. Given the assortment of agents, dosing, benefits, risks, and utilization in the critical care setting, there may be difficulty with identifying the appropriate places for use of corticosteroids in therapy. There currently exists no comprehensive report detailing the use of corticosteroids in the aforementioned disease states within the critical care setting. This narrative review sets out to describe these in detail.

The association between blood eosinophils and clinical outcome of acute exacerbations of chronic obstructive pulmonary disease: A systematic review and meta-analysis

OBJECTIVES

Studies have shown an association between eosinophilia and clinical outcomes in acute exacerbation of chronic obstructive pulmonary disease (AECOPD). However, contradictory findings exist. Our study aims to systematically evaluate the association between elevated peripheral blood eosinophils and clinical outcome of patients with AECOPD.

METHODS

An electronic search was conducted for relevant studies published from database inception to February 28, 2023, on PubMed, EMBASE, Cochrane Library, and Web of Science. The analysis covered studies on the correlation between EOS AECOPD and mortality, hospital stay duration, readmission and hospitalization rates, and invasive mechanical ventilation. Where applicable, relative risk (RR) and weighted mean difference (WMD) were extracted, pooled, and assessed using meta-analysis. Sensitivity analysis was performed to explore the source of heterogeneity.

RESULTS

Fifteen high-quality studies including 14 cohort studies and one case-control study were included in the meta-analysis. Compared with non-eosinophilic AECOPD patients, those with eosinophilic AECOPD had a lower risk of mortality (RR = 0.65, 95 % confidence interval [CI] 0.54, 0.77, P < 0.001), shorter length of hospital stay (WMD = -1.56, 95%CI -2.16, -0.96, P < 0.001), and higher readmission rate (RR = 1.07, 95%CI 1.01,1.13, P = 0.029). No difference was found concerning the rate of hospitalization and invasive mechanical ventilation between the two groups.

CONCLUSION

Individuals diagnosed with eosinophilic AECOPD had a reduced mortality rate, a truncated period of hospitalization, and an insubstantial increase in the probability of readmission relative to their non-eosinophilic AECOPD counterparts. The level of eosinophils in blood has been shown to serve as a potential predictive biomarker for AECOPD patients.

Blood eosinophil-guided oral prednisolone for COPD exacerbations in primary care in the UK (STARR2): a non-inferiority, multicentre, double-blind, placebo-controlled, randomised controlled trial

BACKGROUND

Systemic glucocorticoids are recommended for use in chronic obstructive pulmonary disease (COPD) exacerbations; however, there is increased harm associated with their use. We hypothesised that the use of eosinophil biomarker-directed oral prednisolone therapy at the time of an exacerbation of COPD was effective at reducing prednisolone use without affecting adverse outcomes.

METHODS

The studying acute exacerbations and response (STARR2) study was a multicentre, randomised, double-blind, placebo-controlled trial conducted in 14 primary care practices in the UK. We included adults (aged ≥40 years), who were current or former smokers (with at least a 10 pack year smoking history) with a diagnosis of COPD, defined as a post-bronchodilator FEV1/forced vital capacity ratio of less than 0·7 previously recorded by the primary care physician, and a history of at least one exacerbation in the previous 12 months requiring systemic corticosteroids with or without antibiotics. All study staff and participants were masked to study group allocation and to treatment allocation. Participants were randomly assigned (1:1) to blood eosinophil-directed treatment (BET; to receive oral prednisolone 30 mg once daily if eosinophil count was high [≥2%] or placebo if eosinophil count was low [<2%]) or to standard care treatment (ST; to receive prednisolone 30 mg once daily irrespective of the point-of-care eosinophil result). Treatment was prescribed for 14 days and all patients also received antibiotics. The primary outcome was the rate of treatment failure, defined as any need for re-treatment with antibiotics or steroids, hospitalisation for any cause, or death, assessed at 30 days after exacerbation in the modified intention-to-treat population. Participants were eligible for re-randomisation at further exacerbations (with a maximum of four exacerbations per participant). A safety analysis was conducted on all randomly assigned participants. Although designed as a superiority trial, after identification of an error in the randomisation code before data lock the study converted to show non-inferiority. An upper margin of 1·105 for the 95% CI was defined as the non-inferiority margin. This study was registered with EudraCT, 2017-001586-24, and is complete.

FINDINGS

Between Nov 6, 2017, and April 30, 2020, 308 participants were recruited from 14 general practices. 144 exacerbations (73 in the BET group and 71 in the ST group) from 93 participants (mean age 70 years [range 46-84] and mean percent predicted FEV1 60·9% [SD 19·4]; 52 [56%] male and 41 [44%] female; ethnicity data was not collected]) were included in the modified intention-to-treat analysis. There were 14 (19%) treatment failures at 30 days post-exacerbation in the BET group and 23 (32%) in the ST group; we found a large non-significant estimated effect between BET and ST (RR 0·60 [95% CI 0·33-1·04]; p=0·070) in reducing treatment failures after a COPD exacerbation. The non-inferiority analysis supported that BET was non-inferior to ST. Frequency of adverse events were similar between the study groups; glycosuria (2/102 [2%] in BET group and 1/101 [1%] in the ST group) and hospital admission for COPD exacerbation (2/102 [2%] in BET group and 1/101 [1%] in the ST group) were the two most common adverse events in both groups. No deaths occurred in the study.

INTERPRETATION

Blood eosinophil-directed prednisolone therapy at the time of an acute exacerbation of COPD is non-inferior to standard care and can be used to safely reduce systemic glucocorticoid use in clinical practice.

FUNDING

National Institute for Health and Care Research.

The Prognostic Value of Blood Eosinophil Level in AECOPD is Influenced by Corticosteroid Treatment During Hospitalization

PURPOSE

Blood eosinophil is a promising biomarker for phenotyping patients with acute exacerbation of COPD (AECOPD). We aimed to evaluate the prognostic value of eosinophil on short- and long-term outcomes stratified by corticosteroid treatment among AECOPD inpatients.

PATIENTS AND METHODS

In this retrospective cohort study, we included patients hospitalized for AECOPD from July 2013 to June 2021 in Beijing, China. Clinical data were collected from electronic medical records. The blood eosinophil count was measured within 24h after admission. Eosinophilic AECOPD was defined as having an eosinophil percentage ≥ 2%. The study outcomes were length of stay (LOS), treatment failure, and AECOPD readmission risk within 3 years of discharge. Multivariable models were used to analyze the associations between blood eosinophil count and outcomes stratified by corticosteroid treatment during hospitalization.

RESULTS

A total of 2406 AECOPD patients were included. The median LOS of AECOPD patients was 10 (interquartile range: 8-14) days. The eosinophil percentage was negatively associated with LOS (P-trend=0.014). Compared with the non-eosinophilic AECOPD group, the eosinophilic group had a 58% lower risk of treatment failure (OR=0.42, 95% CI: 0.20-0.89) in patients treated with systemic corticosteroids, but no association was observed in those treated with inhaled corticosteroids (ICS) only (OR=0.95, 95% CI: 0.60-1.52). The eosinophilic group had an increased risk of 90-day re-admission in patients treated with ICS only (HR=1.51, 95% CI: 1.00-2.29), but not in patients treated with systemic corticosteroids during hospitalization (HR=0.67, 95% CI: 0.39-1.15). No statistically significant results were found for 180-day, 1-year, or 3-year readmission risk.

CONCLUSION

Elevated blood eosinophils in AECOPD were associated with shorter length of stay and improved response to treatment with systemic corticosteroids, but not inhaled corticosteroids. Our study suggested that a therapeutic approach of using systemic corticosteroid may benefit patients present with eosinophilic AECOPD.

Multicentre double-blind randomised controlled trial of systematic corticosteroid therapy in patients with acute exacerbations of chronic obstructive pulmonary disease admitted to hospital with higher eosinophil levels: the ECHO protocol

INTRODUCTION

Corticosteroid is one of the most commonly used medications in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD). The increasing understanding of these side-effects of systematic corticosteroids and their better response to treatment among patients with COPD with higher blood eosinophil counts has led to an interest in a more targeted approach to systematic corticosteroid treatment. However, there is a lack of evidence from high-quality randomised controlled trial (RCT) studies about whether initial systematic corticosteroids should be given to patients with AECOPD with elevated eosinophilia. The aim of the present research was to test this hypothesis.

METHODS AND ANALYSIS

This is a multicentre, double-blind, superiority RCT in the respiratory departments of 12 general hospitals in China. It is anticipated that 456 patients with AECOPD with a blood eosinophil count >2% or >300 cells/µL at admission will be recruited. Eligible patients will be randomised (1:1) to the intervention group receiving 40 mg oral prednisone daily or identical-appearing placebo (control group) for five consecutive days. Follow-up visits are performed during hospitalisation, followed by clinic interviews on days 30, 60 and 90 after discharge. The primary outcome is treatment failure rates comprising requiring or receiving invasive or non-invasive mechanical ventilation, requiring or transferring to intensive care unit during the index hospitalisation, length of index hospitalisation longer than 14 days, death during the index hospitalisation or within 30 days after discharge and readmission with acute exacerbations of COPD within 30 days after discharge. The results of this trial will provide insight into the value of using blood eosinophil counts as a biomarker of eosinophilic exacerbation and initiating systematic corticosteroid treatment for patients with AECOPD with higher eosinophil levels.

ETHICS AND DISSEMINATION

This study was approved by Beijing Chaoyang Hospital Institutional Review Board (approval number: 2020-KE-544) and the main results and secondary results will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05059873.

Application of the Rome severity classification of COPD exacerbations in a real-world cohort of hospitalised patients

Background

Recently, the Rome classification was proposed in which objective and readily measurable variables were integrated to mark exacerbations of COPD (ECOPD) severity. The aim of this study is to investigate the distribution of a real-world patient population with hospitalised ECOPD according to the current classification across the newly proposed severity classification. We assume that a significant proportion of hospitalised patients will have a mild or moderate event.

Methods

The Rome classification was applied to a cohort of 364 COPD patients hospitalised at the Department of Respiratory Medicine of Maastricht University Medical Center (MUMC) with a severe ECOPD. Differences in in-hospital, 30- and 90-day mortality were compared between mild, moderate and severe ECOPD according to the new classification. Moreover, data were stratified by the different severity classes and compared regarding general disease characteristics and clinical parameters.

Results

According to the Rome proposal, 52 (14.3%) patients had a mild ECOPD, 204 (56.0%) a moderate and 108 (29.7%) a severe ECOPD. In-hospital mortality in mild, moderate and severe events was 3.8%, 6.9% and 13.9%, respectively. Most clinical parameters indicated a significantly worse condition in patients classified in the severe group, compared to those in mild or moderate groups.

Conclusion

Most of the events, traditionally all classified as severe because of the hospitalisation, were classified as moderate, while almost 15% were mild. The results of this study provide insight into the heterogeneity of hospitalised ECOPD and show that the newly proposed Rome criteria can differentiate between events with different short-term mortality rates.

In-hospital antibiotic use for severe chronic obstructive pulmonary disease exacerbations: a retrospective observational study

BACKGROUND

The use of antibiotics in mild to severe acute exacerbations of chronic obstructive pulmonary disease (COPD) remains controversial.

AIM

To explore in-hospital antibiotic use in severe acute exacerbations of COPD (AECOPD), to analyze determinants of in-hospital antibiotic use, and to investigate its association with hospital length of stay (LOS) and in-hospital mortality.

METHODS

A retrospective, observational study was conducted in Ghent University Hospital. Severe AECOPD were defined as hospitalizations for AECOPD (ICD-10 J44.0 and J44.1) discharged between 2016 and 2021. Patients with a concomitant diagnosis of pneumonia or 'pure' asthma were excluded. An alluvial plot was used to describe antibiotic treatment patterns. Logistic regression analyses identified determinants of in-hospital antibiotic use. Cox proportional hazards regression analyses were used to compare time to discharge alive and time to in-hospital death between antibiotic-treated and non-antibiotic-treated AECOPD patients.

RESULTS

In total, 431 AECOPD patients (mean age 70 years, 63% males) were included. More than two-thirds (68%) of patients were treated with antibiotics, mainly amoxicillin-clavulanic acid. In multivariable analysis, several patient-related variables (age, body mass index (BMI), cancer), treatment-related variables (maintenance azithromycin, theophylline), clinical variables (sputum volume and body temperature) and laboratory results (C-reactive protein (CRP) levels) were associated with in-hospital antibiotic use independent of sputum purulence, neutrophil counts, inhaled corticosteroids and intensive care unit of which CRP level was the strongest determinant. The median hospital LOS was significantly longer in antibiotic-treated patients (6 days [4-10]) compared to non-antibiotic-treated patients (4 days [2-7]) (p < 0.001, Log rank test). This was indicated by a reduced probability of hospital discharge even after adjustment for age, sputum purulence, BMI, in-hospital systemic corticosteroid use and forced expiratory volume in one second (FEV₁) (adjusted hazard ratio 0.60; 95% CI 0.43; 0.84). In-hospital antibiotic use was not significantly associated with in-hospital mortality.

CONCLUSIONS

In this observational study in a Belgian tertiary hospital, in-hospital antibiotic use among patients with severe AECOPD was determined by the symptom severity of the exacerbation and the underlying COPD severity as recommended by the guidelines, but also by patient-related variables. Moreover, in-hospital antibiotic use was associated with a longer hospital stay, which may be linked to their disease severity, slower response to treatment or 'harm' due to antibiotics.

TRIAL REGISTRATION

Number: B670201939030; date of registration: March 5, 2019.

Eosinopenia as a Prognostic Biomarker for Noninvasive Ventilation Use in COPD Exacerbations

BACKGROUND

In recent years, blood eosinophils have been evaluated as a surrogate biomarker for eosinophilic airway inflammation and as a prognostic indicator of the outcomes of hospitalized COPD subjects. During an exacerbation of COPD, eosinopenia has been proposed as a prognostic marker of adverse outcomes.

OBJECTIVES

The aim of the present post hoc analysis was to elucidate the effectiveness of blood eosinophils for predicting the need of NIV in subjects with COPD exacerbation.

METHODS

Consecutive subjects admitted to a hospital for COPD exacerbation were included in the analysis. The eosinophil count from the first complete blood count was used to designate the eosinophil groups. The relationship between the clinical characteristics and blood eosinophil counts, as dichotomized using 150 cells/μL, was evaluated. Results Subjects with blood eosinophil number < 150 k/μL had a more severe disease on admission compared to subjects with ≥150 k/μL, regarding pH 7.400 (7.36, 7.44) vs. 7.42 (7.38, 7.45), p = 0.008, PO₂/FiO₂ levels 238.1 (189.8, 278.6) vs. 276.2 (238.2, 305.6), p < 0.001, CRP (mg/L) levels 7.3 (3.1, 19.9) vs. 3.5 (0.7, 7.8), p < 0.001 and required a longer hospital stay (days) 10.0 (8.0, 14.0) vs. 5.0 (3.0, 7.0) p < 0.001 respectively. The number of blood eosinophils correlated with the levels of CRP upon admission (p < 0.001, r = -0.334), with arterial pH upon admission (p < 0.030, r = 0.121), with PO₂/FiO₂ (p < 0.001, r = -0.248), and with duration of hospital stay (p < 0.001, r = -0.589). In the multinomial logistic regression analysis, blood eosinophil count < 150 k/μL was an independent predictor of the use of NIV during hospital stay.

CONCLUSION

During COPD exacerbation, low blood eosinophil levels upon admission are related to more severe disease and can be used as a predictor of the need of NIV. Further prospective studies are needed to identify the use of blood eosinophil levels as a predictor of unfavorable outcomes.

Association of Upon-Diagnosis Blood Eosinophilic Count with Frequency and Severity of Annual Exacerbation in Chronic Obstructive Pulmonary Disease: A Prospective Longitudinal Analysis

Introduction

There is a controversy regarding the relationship between blood eosinophil count and COPD exacerbation. We aimed to determine whether peripheral eosinophils upon COPD diagnosis could affect the frequency and severity of annual acute exacerbation of COPD (AECOPD).

Methods

This prospective study was conducted on 973 newly diagnosed COPD patients who were under 1-year follow-up in a pulmonology center in Iran. The Cox proportional model, polynomial regression, and receiver operator characteristic curves were conducted to evaluate the impact of the eosinophil levels on AECOPD. A linear regression model was conducted to evaluate the continuous association of eosinophilic count with AECOPDs.

Results

Patients with eosinophil >200 cells/microliter were higher pack-year smokers with more pulmonary hypertension prevalence compared to COPD patients with <200 cells/microliter. There was a positive correlation between the eosinophilic count and the frequency of AECOPDs. Eosinophil >900 cells/microliter and eosinophil >600 cells/microliter had a sensitivity of 71.1% and 64.3%, respectively, in predicting the occurrence of more than one AECOPD. Eosinophilic count cutoff of 800 cells/microliter had the highest Youden index with sensitivity and specificity of 80.2% and 76.6%, respectively, for incident AECOPD in newly diagnosed patients. Using a linear model, increasing 180 cells/microliter in serum eosinophils was associated with further exacerbation. Evaluating gender, BMI, smoking pack-year, FEV1/FVC, CAT score, GOLD score, pulmonary hypertension, annual influenza, pneumococcal vaccinations, leukocytosis, and blood eosinophils, only blood eosinophils (hazard ratio (HR) = 1.44; 95% confidence interval = 1.33-2.15; p value = 0.03) and GOLD score (HR = 1.19; 95% CI = 1.30-1.52; p value = 0.03) were found as independent risk factors of AECOPD >3 episodes/year. Requirement for ICU admission, invasive ventilation, and mortality rate due to AECOPDs was similar between eosinophilic and noneosinophilic groups.

Conclusion

Eosinophilia upon COPD diagnosis is a factor of recurrent AECOPDs. To reduce the risk of AECOPDs and the burden of disease, clinicians may consider inhaler corticosteroids and domiciliary oxygen with a lower threshold for eosinophilic-COPD patients regardless of their clinical status.

Measurement of Blood Eosinophils in Asthma and Chronic Obstructive Pulmonary Disease

Eosinophils are important effector cells in airway inflammation, as pleiotropy and heterogeneity can be linked to various pathophysiologies in asthma and chronic obstructive pulmonary disease (COPD). Sputum eosinophils can reflect the heterogeneity of airway inflammation, and owing to their traits, blood eosinophils can be a surrogate and potential biomarker for managing both conditions. Blood eosinophils are activated via the stimulation of type 2 cytokines, such as interleukin (IL)-5, IL-4/13, granulocyte-macrophage colony-stimulating factor, IL-33, and thymic stromal lymphopoietin. There is sufficient evidence to support the relationship between the blood eosinophil count and clinical outcomes, including pulmonary function decline, exacerbations, all-cause mortality, and treatment response to inhaled corticosteroids and biologics. Thus, there is growing interest in the use of blood eosinophils for the management of these diseases. Compiling recent evidence, we herein review the significance of measuring blood eosinophils in asthma and COPD.

Blood and sputum eosinophilia in COPD exacerbation

Background

Exacerbations in chronic obstructive pulmonary disease (COPD) are major contributors to worsening lung function, impaired quality of life, emergency healthcare use, and COPD-related mortality. COPD exacerbations are heterogeneous in terms of airway inflammation and etiology.

Objectives

To assess the relation between blood and sputum eosinophils and COPD exacerbation.

Subjects and methods

Prospective cohort study, conducted on 100 COPD patients presented in outpatient clinic. All patients were subjected to medical history including: occupational history, smoking history, comorbidity, number of exacerbations in last year and their degree, history of admission in the last year and treatment taken for COPD. Modified Medical Research Council scale of dyspnea, peak expiratory flow rate, oxygen saturation using pulse oximetry. Complete blood count with differential eosinophilic count. Sputum sample differential cell count was done.

Results

The eosinophil level in blood before and after treatment showed a significant positive correlation with the number of hospital admission in the last year (r = 0.29; P = 0.003 and r = 0.3; P = 0.002, respectively). Regarding the eosinophil level either in blood or in sputum, it showed significant statistical elevation in patients not using steroid treatment in comparison to patients who used systemic or inhaled steroid treatments (P < 0.001 and 0.004, respectively).

Conclusion

Blood eosinophil count can be used as a severity marker of COPD exacerbations. The eosinophil levels, either in blood or sputum, were significantly correlated with the degree of exacerbation. Sputum eosinophilia can also predict the risk of hospitalization. In addition, blood eosinophil count can direct the use of oral corticosteroids in exacerbation.

Impact of Acute Exacerbation and Its Phenotypes on the Clinical Outcomes of Chronic Obstructive Pulmonary Disease in Hospitalized Patients: A Cross-Sectional Study

Acute exacerbations of COPD (AECOPD) are clinically significant events having therapeutic and prognostic consequences. However, there is a lot of variation in its clinical manifestations described by phenotypes. The phenotypes of AECOPD were categorized in this study based on pathology and exposure. In our cross-sectional study, conducted between 1 January 2016 to 31 December 2020, the patients were categorized into six groups based on pathology: non-bacterial and non-eosinophilic; bacterial; eosinophilic; bacterial infection with eosinophilia; pneumonia; and bronchiectasis. Further, four groups were classified based on exposure to tobacco smoke (TS), biomass smoke (BMS), both, or no exposure. Cox proportional-hazards regression analyses were performed to assess hazard ratios, and Kaplan-Meier analysis was performed to assess survival, which was then compared using the log-rank test. The odds ratio (OR) and independent predictors of ward admission type and length of hospital stay were assessed using binomial logistic regression analyses. Of the 2236 subjects, 2194 were selected. The median age of the cohort was 67.0 (60.0 to 74.0) and 75.2% were males. Mortality rates were higher in females than in males (6.2% vs. 2.3%). AECOPD-B (bacterial infection) subjects [HR 95% CI 6.42 (3.06-13.46)], followed by AECOPD-P (pneumonia) subjects [HR (95% CI: 4.33 (2.01-9.30)], were at higher mortality risk and had a more extended hospital stay (6.0 (4.0 to 9.5) days; 6.0 (4.0 to 10.0). Subjects with TS and BMS-AECOPD [HR 95% CI 7.24 (1.53-34.29)], followed by BMS-AECOPD [HR 95% CI 5.28 (2.46-11.35)], had higher mortality risk. Different phenotypes have different impacts on AECOPD clinical outcomes. A better understanding of AECOPD phenotypes could contribute to developing an algorithm for the precise management of different phenotypes.

Blood Eosinophils and Exhaled Nitric Oxide: Surrogate Biomarkers of Airway Eosinophilia in Stable COPD and Exacerbation

In recent years, tremendous efforts have been devoted to characterizing the inflammatory processes in chronic obstructive pulmonary disease (COPD) in order to provide more personalized treatment for COPD patients. While it has proved difficult to identify COPD-specific inflammatory pathways, the distinction between eosinophilic and non-eosinophilic airway inflammation has gained clinical relevance. Evidence has shown that sputum eosinophil counts are increased in a subset of COPD patients and that these patients are more responsive to oral or inhaled corticosteroid therapy. Due to feasibility issues associated with sputum cell profiling in daily clinical practice, peripheral blood eosinophil counts and fractional exhaled nitric oxide levels have been evaluated as surrogate biomarkers for assessing the extent of airway eosinophilia in COPD patients, both in stable disease and acute exacerbations. The diagnostic value of these markers is not equivalent and depends heavily on the patient’s condition at the time of sample collection. Additionally, the sensitivity and specificity of these tests may be influenced by the patient’s maintenance treatment. Overall, eosinophilic COPD may represent a distinct disease phenotype that needs to be further investigated in terms of prognosis and treatment outcomes.

Prognostic risk factors for moderate-to-severe exacerbations in patients with chronic obstructive pulmonary disease: a systematic literature review

Background

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. COPD exacerbations are associated with a worsening of lung function, increased disease burden, and mortality, and, therefore, preventing their occurrence is an important goal of COPD management. This review was conducted to identify the evidence base regarding risk factors and predictors of moderate-to-severe exacerbations in patients with COPD.

Methods

A literature review was performed in Embase, MEDLINE, MEDLINE In-Process, and the Cochrane Central Register of Controlled Trials (CENTRAL). Searches were conducted from January 2015 to July 2019. Eligible publications were peer-reviewed journal articles, published in English, that reported risk factors or predictors for the occurrence of moderate-to-severe exacerbations in adults age ≥ 40 years with a diagnosis of COPD.

Results

The literature review identified 5112 references, of which 113 publications (reporting results for 76 studies) met the eligibility criteria and were included in the review. Among the 76 studies included, 61 were observational and 15 were randomized controlled clinical trials. Exacerbation history was the strongest predictor of future exacerbations, with 34 studies reporting a significant association between history of exacerbations and risk of future moderate or severe exacerbations. Other significant risk factors identified in multiple studies included disease severity or bronchodilator reversibility (39 studies), comorbidities (34 studies), higher symptom burden (17 studies), and higher blood eosinophil count (16 studies).

Conclusions

This systematic literature review identified several demographic and clinical characteristics that predict the future risk of COPD exacerbations. Prior exacerbation history was confirmed as the most important predictor of future exacerbations. These prognostic factors may help clinicians identify patients at high risk of exacerbations, which are a major driver of the global burden of COPD, including morbidity and mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02123-5.

Incorporating Biomarkers in COPD Management: The Research Keeps Going

Globally, chronic obstructive pulmonary disease (COPD) remains a major cause of morbidity and mortality, having a significant socioeconomic effect. Several molecular mechanisms have been related to COPD including chronic inflammation, telomere shortening, and epigenetic modifications. Nowadays, there is an increasing need for novel therapeutic approaches for the management of COPD. These treatment strategies should be based on finding the source of acute exacerbation of COPD episodes and estimating the patient’s own risk. The use of biomarkers and the measurement of their levels in conjunction with COPD exacerbation risk and disease prognosis is considered an encouraging approach. Many types of COPD biomarkers have been identified which include blood protein biomarkers, cellular biomarkers, and protease enzymes. They have been isolated from different sources including peripheral blood, sputum, bronchoalveolar fluid, exhaled air, and genetic material. However, there is still not an exclusive biomarker that is used for the evaluation of COPD but rather a combination of them, and this is attributed to disease complexity. In this review, we summarize the clinical significance of COPD-related biomarkers, their association with disease outcomes, and COPD patients’ management. Finally, we depict the various samples that are used for identifying and measuring these biomarkers.

Low Eosinophil Phenotype Predicts Noninvasive Mechanical Ventilation Use in Patients with Hospitalized Exacerbations of COPD

Rationale

Objective

Methods

Results

Conclusion

Long‐term oxygen treatment need is less frequent in eosinophilic COPD patients

Introduction

Methods

Results

Conclusion

Blood eosinophils in COPD: friend or foe?

INTRODUCTION

The pathogenesis of chronic obstructive pulmonary disease (COPD) is highly complex and the underlying cellular and molecular mechanisms remain poorly understood.

AREAS COVERED

COPD has been traditionally associated with neutrophilic inflammation of the bronchi, but in the last decade, studies have demonstrated that eosinophils may also migrate into the lower airways of patients with COPD and their increased numbers can be noticed during exacerbations as well as stable disease. In this review, we present clinical characteristics of eosinophilic COPD, as well as the role of eosinophils as a biomarker-guided therapy in COPD. A systematic research using the database of Pubmed up to February 2021 was performed. The terms we searched were eosinophilic inflammation, COPD, COPD phenotypes, COPD exacerbations, corticosteroids in COPD, and monoclonal antibodies in COPD.

EXPERT OPINION

Blood eosinophil levels show strong potential as a prognostic and theragnostic biomarker in the clinical management of COPD being at the moment the most reliable biomarker. The lack of a certain cutoff value of blood eosinophils as guidance for treatment with ICS and biologic therapies and the uncertainty regarding the stability of eosinophilia and eosinophilic phenotype through the course of COPD remain as unmet dilemmas and problems.

Variability of blood eosinophil count and prognosis of COPD exacerbations

BACKGROUND

Eosinophils in peripheral blood are one of the emerging biomarkers in chronic obstructive pulmonary disease (COPD) patients. However, when analysing the relationship between peripheral eosinophilia and COPD prognosis, highly variable results are obtained. The aim of our study is to describe the serum eosinophilia levels in COPD patients and to analyse their relationship to prognosis following hospital admission.

METHODS

A prospective observational study was conducted from 1 October 2016 to 1 October 2018 in the following Spanish centres: Salnés County Hospital in Vilagarcía de Arousa, Arquitecto Marcide Hospital in Ferrol and the University Hospital Complex in Santiago de Compostela. The patients were classified using three cut-off points of blood eosinophil count (BEC): 150 cells/µL, 300 cells/µL, and 400 cells/µL; in addition, the peripheral BEC was analysed on admission.

RESULTS

615 patients were included in the study, 86.2% male, mean age 73.9 years, and mean FEV1 52.7%. The mean stay was 8.4 days, and 6% of all patients were readmitted early. No significant relationship was observed between the BEC, neither in the stable phase nor in the acute phase, and hospital stay, readmissions, deaths during admission, the need for intensive care, or the condition of frequent exacerbator.

CONCLUSION

The results of our study do not seem to support the usefulness of BEC as a COPD biomarker.KEY MESSAGESThere is evidence that BEC participates in pathophysiological mechanisms of the COPD.BEC may be useful as a biomarker in COPD for aspects such as the optimization of treatments.We did not find any relationship between BEC levels and prognosis following hospital admission for AECOPD.

Stability of blood eosinophils in acute exacerbation of chronic obstructive pulmonary disease and its relationship to clinical outcomes: a prospective cohort study

BACKGROUND

The clinical value of blood eosinophils and their stability in chronic obstructive pulmonary disease (COPD) remains controversial. There are limited studies on association between the stability of blood eosinophils in acute exacerbation of COPD (AECOPD) and clinical outcomes. This study aimed to evaluate the stability of blood eosinophils in hospitalized AECOPD and its relationship to clinical outcomes.

METHODS

This prospective observational study recruited patients hospitalized with AECOPD from November 2016 to July 2020. The eligible patients were divided into four groups according to their blood eosinophil counts at admission and discharge: persistently < 300 cells/μl (LL), < 300 cells/μl at admission but ≥ 300 cells/µl at discharge (LH), ≥ 300 cells/μl at admission but < 300 cells/µl at discharge (HL), and persistently ≥ 300 cells/μl (HH). Cox hazard analyses were used to study the association between eosinophil changes and exacerbations or mortality.

RESULTS

In 530 patients included, 90 (17.0%) had a high blood eosinophil count (BEC) ≥ 300 cells/µl at admission but 32 (35.6%) of them showed a decreased BEC at discharge. The proportions and distribution for group LL, LH, HL, and HH were 381 (71.9%), 59 (11.1%), 32 (6.0%), and 58 (10.9%), respectively. During hospitalization, the LH group had a higher C-reactive protein level, higher rate of intensive care unit (ICU) admission, and higher total cost. The length of hospital stay of the LH group was longer compared with group LL, HL, or HH (P = 0.002, 0.017, and 0.001, respectively). During a follow-up of 12 months, the HH group was associated with a higher risk of moderate-to-severe exacerbations compared to the LL group (hazard ratio 2.00, 95% confidence interval 1.30-3.08, P = 0.002). Eosinophil changes had no significant association with mortality at 12 months. Sensitivity analyses in patients without asthma and without use of systemic corticosteroids prior to admission did not alter the results.

CONCLUSIONS

More attention should be paid to the LH group when evaluating the short-term prognosis of AECOPD. A persistently high BEC was a risk factor for long-term exacerbations. Eosinophil changes during hospitalization could help to predict outcomes.

From Biomarkers to Novel Therapeutic Approaches in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a heterogeneous and complex disorder. In this review, we provided a comprehensive overview of biomarkers involved in COPD, and potential novel biological therapies that may provide additional therapeutic options for COPD. The complex characteristics of COPD have made the recommendation of a generalized therapy challenging, suggesting that a tailored, personalized strategy may lead to better outcomes. Existing and unmet needs for COPD treatment support the continued development of biological therapies, including additional investigations into the potential clinical applications of this approach.

Eosinophilic Chronic Obstructive Pulmonary Disease

Recent therapeutic advances in the management of asthma have underscored the importance of eosinophilia and the role of pro-eosinophilic mediators such as IL-5 in asthma. Given that a subset of patients with COPD may display peripheral eosinophilia similar to what is observed in asthma, a number of recent studies have implied that eosinophilic COPD is a distinct entity. This review will seek to contrast the mechanisms of eosinophilia in asthma and COPD, the implications of eosinophilia for disease outcome, and review current data regarding the utility of peripheral blood eosinophilia in the management of COPD patients.

The Role of Blood Eosinophils in the Management of COPD: An Attempt to Answer the Important Clinical Questions

Blood eosinophils have been proposed as a surrogate biomarker of airway eosinophilia that can be used for treatment decisions in patients with COPD, mainly for the identification of candidates for the initiation or withdrawal of therapy with inhaled corticosteroids, as well as for the identification of patients at future risk of exacerbations. In this manuscript we review the recent literature on blood eosinophils in the management of patients with COPD, in an attempt to answer the major questions that are relevant for the practicing clinician. A growing body of evidence suggests that eosinophilic COPD may constitute a separate phenotype of the disease with distinct clinical features and blood eosinophils may represent a potential candidate surrogate marker for specific COPD patients. Several points still need to be clarified, including the role of eosinophils for the identification of candidates for future COPD therapies, yet blood eosinophils plausibly represent the most dependable and promising biomarker for the precision management of COPD today.

Characterization Associated with the Frequent Severe Exacerbator Phenotype in COPD Patients

Background

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease with exacerbations causing hospitalizations, morbidity, and mortality. COPD exacerbation causes a substantial health impact, and its subtypes might differ in prognosis and treatment response.

Methods

This study evaluated the factors of COPD exacerbations and explored the probabilities of frequent severe COPD exacerbations. Categorical and continuous variables between groups were compared. The hazard ratio (HR) and the probability of no hospital readmission were also estimated.

Results

A total of 617 COPD patients were enrolled and comprised the frequent exacerbator (N = 226) and the non-frequent exacerbator (N = 391) groups. The frequent exacerbator group significantly displayed a higher eosinophil count (EC; p=0.004), a higher percentage of the frequent severe acute exacerbation history before the index hospitalization (IH; p < 0.001), a lower FEV1 value (p=0.001), and a higher triple combination inhaler prior and following the IH (p < 0.001 and p=0.002) than the non-frequent exacerbator one. Increasing age (aOR of 1.02), higher EC (aOR of 1.09), and lower FEV1 value (aOR of 0.72) were significantly associated with an increased hospital readmission risk. The readmission rate and risk were higher in patients with a history of frequent severe acute exacerbation (aHR of 3.38) than those without severe acute exacerbation. Cases treated with the triple combination inhaler before the IH had a higher readmission rate and risk than non-users.

Conclusion

Patients with EC ≥2%, FEV1 <50%, or frequent severe acute exacerbation history before the IH have a higher risk of being diagnosed with a frequent exacerbator phenotype. Besides, higher age, triple combination inhaler before the IH, and smoking might be independently correlated with the frequent readmission risk within 1-year post-exacerbation. A better comprehension of the COPD exacerbation mechanism may further identify the best course of preventative strategy and lead to novel interventions.

Treatment Response Biomarkers in Asthma and COPD

Chronic obstructive pulmonary disease (COPD) and asthma are two of the most common chronic diseases worldwide. Both diseases are heterogenous and complex, and despite their similarities, they differ in terms of pathophysiological and immunological mechanisms. Mounting evidence supports the presence of several phenotypes with various responses to treatment. A systematic and thorough assessment concerning the diagnosis of both asthma and COPD is crucial to the clinical management of the disease. The identification of different biomarkers can facilitate targeted treatment and monitoring. Thanks to the presence of numerous immunological studies, our understanding of asthma phenotypes and mechanisms of disease has increased markedly in the last decade, and several treatments with monoclonal antibodies are available. There are compelling data that link eosinophilia with an increased risk of COPD exacerbations but a greater treatment response and lower all-cause mortality. Eosinophilia can be considered as a treatable trait, and the initiation of inhaled corticosteroid in COPD patients with eosinophilia is supported in many studies. In spite of advances in our understanding of both asthma and COPD in terms pathophysiology, disease mechanisms, biomarkers, and response to treatment, many uncertainties in the management of obstructive airways exist.

Eosinophilic phenotype was associated with better early clinical remission in elderly patients but not middle-aged patients with acute exacerbations of COPD

BACKGROUND

There is limited evidence of the relationship between peripheral blood eosinophils and clinical remission of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) at different ages, especially in elderly patients, which was the objective of the present study.

METHODS

This retrospective study stratified patients by age (elderly patients >65 years old or middle-aged patients between 45 and 65 years old) and analysed the relationship between blood eosinophils (≥2% or <2%) and AECOPD clinical remission at observing time points of 7, 14, 21 and 28 days of hospitalisation. Student's t tests, Mann-Whitney U tests, Chi-squared or Fisher's exact tests were conditionally used to compare difference between groups. The unadjusted or adjusted Cox proportional hazards model was used to analyse the association between blood eosinophilic levels and cumulative clinical remission.

RESULTS

Of 703 AECOPD cases analysed, 616 were elderly people (>65 years), 312 of whom had eosinophilic exacerbations. There were statistically significant differences in leucocytes, eosinophils, neutrophils, lymphocytes, monocytes, high-sensitivity C-reactive protein levels (hs-CRP), and hospital costs between groups (P < .05, respectively). According to the chi-square analysis, eosinophilic exacerbation had a higher clinical remission rate at 7, 14 and 21 days (all P < .05), but not 28 days (P > .05). Among analysis through adjusted Cox proportional hazards model, eosinophilic exacerbation was significantly associated with a higher cumulative remission rate in elderly patients at 7, 14, 21 days (all P < .05), but not 28 days (P > .05). No significant association was observed in meddle-aged patients at any time points (all P > .05).

CONCLUSION

Eosinophilic exacerbation was associated with better early clinical remission of AECOPD patients during hospitalisation. As stratified by ages, similar results were observed in elderly patients but not middle-aged patients. Blood eosinophils at different ages may be valuable in personalised management for AECOPD.

Effect of COVID-19-Related Lockdown οn Hospital Admissions for Asthma and COPD Exacerbations: Associations with Air Pollution and Patient Characteristics

We conducted a retrospective observational study to assess the hospitalization rates for acute exacerbations of asthma and COPD (chronic obstructive pulmonary disease) during the first imposed lockdown in Athens, Greece. Patient characteristics and the concentration of eight air pollutants [namely, NO (nitrogen monoxide), NO2 (nitrogen dioxide), CO (carbon monoxide), PM2.5 (particulate matter 2.5), PM10 (particulate matter 10), O3 (ozone), SO2 (sulfur dioxide) and benzene] were considered. A total of 153 consecutive hospital admissions were studied. Reduced admissions occurred in the Lockdown period compared to the Pre-lockdown 2020 (p < 0.001) or the Control 2019 (p = 0.007) period. Furthermore, the concentration of 6/8 air pollutants positively correlated with weekly hospital admissions in 2020 and significantly decreased during the lockdown. Finally, admitted patients for asthma exacerbation during the lockdown were younger (p = 0.046) and less frequently presented respiratory failure (p = 0.038), whereas patients with COPD presented higher blood eosinophil percentage (p = 0.017) and count (p = 0.012). Overall, admissions for asthma and COPD exacerbations decreased during the lockdown. This might be partially explained by reduction of air pollution during this period while medical care avoidance behavior, especially among elderly patients cannot be excluded. Our findings aid in understanding the untold impact of the pandemic on diseases beyond COVID-19, focusing on patients with obstructive diseases.

Biomarkers in Chronic Obstructive Pulmonary Disease: Emerging Roles of Eosinophils and Procalcitonin

Antibiotics can improve the prognosis in patients with exacerbation of chronic obstructive pulmonary disease. However, the overuse of antibiotics can carry serious adverse effects for patients (gastrointestinal infections) and for society (bacterial resistance). Likewise, systemic corticosteroids may also help these patients, but also carries severe adverse effects like osteoporosis, muscle loss, and diabetes, in many patients. Whenever safe methods exist to reduce these two treatment modalities, they should be implemented. The blood biomarkers procalcitonin and the fraction of leukocytes known as eosinophil granulocytes have been proven in randomized controlled trials (RCTs), to effectively, significantly, and substantially assist in reducing the use of these two potent, yet toxic medication types. In this review, the background and main clinical results are discussed, explaining the rationale for biomarker-guided clinical decisions. Also, the main expected effects, their sizes, and importantly the limitations to such a strategy are described. Clinical evidence is prioritized with main weight on RCTs and meta-analyses of these and regarding outcomes, and focus is set on the safety of such a biomarker-guided strategy, as well as the effects on medicine reduction. In an epoch of increasing demands to physicians from patients and politicians to cure and reduce symptoms, the Hippocratic phrase of "primum non nocere" or "first, do no harm" seems more than ever of contemporary importance.

Determinants of blood eosinophilia in moderate and severe asthmatic patients during childhood: Evidence from the severe asthma molecular phenotype (SAMP) cohort

BACKGROUND

Asthma is a heterogeneous disease in which the interaction between genetic and environmental factors plays a major role. The significance of blood eosinophil is unclear. The aim of the study was to determine the significance of blood eosinophil count in moderate-to-severe asthmatic children of preschool age and school age.

METHODS

This was a prospective cross-sectional study performed from 2011 to 2015 including children from the severe asthma molecular phenotype (SAMP) cohort at Trousseau Hospital (Paris, France). We included children with severe and moderate asthma, or severe and moderate recurrent wheeze, aged from 1 to 15 years at the time of exploration.

RESULTS

We analyzed data from 402 children: 248 of preschool age and 154 of school age. Blood eosinophil count third quartile thresholds were 322 and 600 cells/μL for the preschool- and school-age groups, respectively. In multivariate analysis, a blood eosinophil count over this threshold was associated with elevated total IgE (OR = 5.33, P < .01), multiple hospitalizations for asthma attacks (OR = 4.96, P = .03), and a maternal history of asthma (OR = 4.91, P = .01) in preschool children; and with staphylococcal toxin-specific IgE (OR = 2.75, P = .03) in children of school age. Random forest analysis reinforced these results.

CONCLUSION

High blood eosinophil count is linked to both atopic features and control of asthma with different parameters associated with these features depending on age.

Blood eosinophil count-guided corticosteroid therapy and as a prognostic biomarker of exacerbations of chronic obstructive pulmonary disease: a systematic review and meta-analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and dyspnea, as well as an increase in the number of leukocytes in the airways, lungs, and pulmonary vessels. A 'One size fits all' approach to COPD patients with different clinical features may be considered outdated. The following are the two major objectives of this meta-analysis: the first is to determine if blood eosinophil counts (BEC) can serve as a prognostic biomarker of COPD outcomes, and the second is to determine which level of BEC is effective for inhaled corticosteroid (ICS) treatment.

METHODS

We searched articles published before 15 May 2021 in the following four electronic databases: Web of Science, Cochrane Library, EMBASE, and PubMed.

RESULTS

A total of 42 studies, comprising a sampling of 188,710 subjects, were summarized and compared in this meta-analysis. The rate ratio (RR) of exacerbations of COPD (ECOPD) between ICS and non-ICS treatment was statistically significant for the COPD patients with a baseline BEC ⩾ 2% or ⩾ 200 cells/μl, RR = 0.82 (0.73, 0.93) or 0.79 (0.70, 0.89) respectively, while the RR of ECOPD between ICS and non-ICS treatment was statistically insignificant for the COPD patients with baseline BEC < 2% or <200 cells/μl, RR = 0.97 (0.87, 1.08) or 0.97 (0.86, 1.08), suggested that ICS therapy was beneficial to the improvement of ECOPD in patients with a baseline BEC ⩾ 2% or BEC ⩾ 200 cells/μl.

CONCLUSION

Our research shows that a BEC ⩾ 200 cells/μl or ⩾2% is likely to become the cutoff value of ICS treatment for ECOPD. Moreover, we believe that the baseline BEC can be used as a biomarker for predicting ECOPD. The stability of BEC requires special attention.

Blood Eosinophils and Clinical Outcomes in Patients With Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Propensity Score Matching Analysis of Real-World Data in China

Background and Objective: Elevated eosinophils in chronic obstructive pulmonary disease (COPD) are recognized as a biomarker to guide inhaled corticosteroids use, but the value of blood eosinophils in hospitalized exacerbations of COPD remains controversial. This study aimed to evaluate the accuracy of eosinophils in predicting clinical outcomes in acute exacerbation of COPD (AECOPD).

Methods: We analyzed data from the acute exacerbation of chronic obstructive pulmonary disease inpatient registry (ACURE) study, which is an ongoing nationwide multicenter, observational real-world study in patients admitted for AECOPD. Data collected between January 2018 and December 2019 in 163 centers were first reviewed. The eligible patients were divided into eosinophilic and non-eosinophilic groups, according to blood eosinophil with 2% of the total leukocyte count as the threshold. Propensity score (PS) matching was performed to adjust for confounders.

Results: A total of 1,566 patients (median age: 69 years; 80.3% male) were included and 42.7% had an eosinophilic AECOPD. Eosinophil count <2% was associated with the development of respiratory failure and pneumonia. After PS matching, 650 pairs in overall patients, 468 pairs in patients with smoking history and 177 pairs in patients without smoking were selected, respectively. Only in patients with smoking history, the non-eosinophilic AECOPD was associated with longer median hospital stays (9 vs. 8 days, P = 0.034), higher dosage of corticosteroid use, higher economic burden of hospitalization, and poorer response to corticosteroid therapy compared to the eosinophilic AECOPD. No significant difference was found in patients without smoking. Eosinophil levels had no relationship with the change of COPD Assessment Test scores and readmissions or death after 30 days.

Conclusion: Elevated eosinophils were associated with better short-term outcomes only in patients with a smoking history. Eosinophil levels cannot be confidently used as a predictor alone for estimating prognosis.

Comparison of Immediate and Sequential Withdrawal of a Systemic Glucocorticoid in the Treatment of Acute Exacerbations of Chronic Obstructive Pulmonary Disease: A Multicenter, Randomized, Double-Blind, Parallel-Controlled, Open-Label Study

Patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) were treated with immediate or sequential withdrawal after 5 days of systemic glucocorticoids. The effects of the two withdrawal methods on the prognosis of patients were compared at 30, 90, 180, and 360 days after discharge. A multicenter, randomized, double-blind, parallel-controlled, open-label study was conducted in the respiratory department of tertiary hospitals in Central China. Patients met inclusion criteria for AECOPD and needed to use systemic glucocorticoids. They were randomly assigned to immediate and sequential withdrawal groups at a 1:1 ratio. The study was completed in August 2020 and is registered at the China Clinical Trials Registry (Chictr.org) (ChiCTR1800018894). According to general data and clinical characteristics, there were no statistically significant differences between the 329 patients in the immediate withdrawal group and the 310 patients in the sequential withdrawal group (P > 0.05). At the 30, 90, 180, and 360-days follow-up, the acute exacerbation frequency, rehospitalization rate, mortality, and intensive care unit (ICU) treatment rate were not significantly different between the immediate withdrawal group and sequential withdrawal group (P > 0.05). The modified Medical Research Council (mMRC) and COPD assessment test (CAT) scores were also not significantly different between the two groups. At the 180- and 360-day follow-up, forced expiratory volume in 1 s (FEV1%) and peak expiratory flow (PEF) were not significantly different between the two groups (P > 0.05). The time from discharge to first acute exacerbation was significantly lower in the immediate withdrawal group (46.12 days) than in sequential withdrawal group (49.02 days) (P < 0.05). The time of stay in the hospital for the first time after discharge was not significantly different between the two groups (P > 0.05). Adverse events were not significantly different between the immediate withdrawal group and sequential withdrawal group (P < 0.05). Subgroup analysis was performed according to age, degree of disease, and relevant indicators. At the 30-day follow-up, the acute exacerbation frequency of patients with advanced age, high global strategy for chronic obstructive lung disease (GOLD), and high fractional exhaled nitric oxide was significantly higher in the immediate withdrawal group than in the sequential withdrawal group (P < 0.05). In addition, according to receiver operating characteristic (ROC) curve analysis, the frequency of acute exacerbations at the 30-day follow-up was significantly higher in patients with age > 63.5 years or GOLD > 3 in the immediate withdrawal group than in the sequential withdrawal group, suggesting that the short-term efficacy was poor.

Peripheral Blood Eosinophils and Nine Years Mortality in COPD Patients

BACKGROUND

Eosinophil counts increase during chronic obstructive pulmonary disease (COPD) exacerbation and influence the response to different agents (such as inhaled and systemic corticosteroids), as well as increase the production of other inflammatory cytokines. However, few studies have evaluated the association between peripheral blood eosinophils with mortality rate.

OBJECTIVE

To evaluate the association between peripheral blood eosinophils and mortality rate in COPD patients over a nine-year period.

STUDY DESIGN AND METHODS

This cohort included 133 COPD patients assessed at baseline by spirometry, pulse oximetry (SpO2), complete blood count, body composition, dyspnea intensity [Modified Medical Research Council (mMRC)] and the six-minute distance test (6MWD). The Kaplan-Meier curve followed by a Log rank test was used to evaluate mortality rate related to eosinophil cutoff point categorization. Multivariate Cox regression analysis was performed to identify the association between eosinophils and mortality with all subjects evaluated at baseline, adjusted for age, gender, mMRC, 6MWT, forced expiratory volume in the first second (FEV1) and SpO2.

RESULTS

Nineteen patients did not complete follow-up and it was not possible to identify the date of death in four others. Therefore, 110 patients were included in the analysis. At baseline, 81% presented ≥150 eosinophil cells and 72% presented ≥2%. We identified a three-fold higher risk of death in those with <2% eosinophils and <150 cells. We did not identify statistical differences when using other cutoff points.

CONCLUSION

The decrease in number of peripheral eosinophils, with cutoff points at 2% and 150 cells, may be associated with a higher risk of death in COPD patients over nine years.

Blood eosinophils as predictor of outcomes in patients hospitalized for COPD exacerbations: a prospective observational study

PURPOSE

In the present prospective multicentre observational study, we evaluated the potential role of blood eosinophils on the outcomes of patients hospitalized for COPD exacerbations.

MATERIAL AND METHODS

Consecutive patients >40 years with a previous COPD diagnosis were recruited. Blood eosinophils were measured on admission prior to the initiation of treatment and were evaluated in three groups (<50, 50-149 and ≥150 cells/μL). Patients received standard care and were followed up for a year.

RESULTS

A total of 388 patients were included (83.5% male, mean age 72 years). Patients with higher blood eosinophils had less dyspnoea (Borg scale), lower C-reactive protein (CRP) and higher PaO₂/FiO₂ (partial pressure for oxygen/fraction of inhaled oxygen), and were discharged earlier (median 11 vs. 9 vs. 5 days for patients with <50, 50-149 and ≥150 cells/μL, respectively). Patients with <50 cells/μL presented higher 30-day and 1-year mortality, whereas there were no differences in moderate/severe COPD exacerbations between the three groups. In a post hoc analysis, treatment with inhaled corticosteroids as per physicians' decision was associated with better exacerbation prevention during follow-up in patients with ≥150 cells/μL.

CONCLUSIONS

Higher blood eosinophils were associated with better outcomes in hospitalized COPD patients, further supporting their use as a prognostic biomarker.

High Blood Eosinophil and YKL-40 Levels, as Well as Low CXCL9 Levels, are Associated with Increased Readmission in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Background

Readmission after hospital discharge is common among patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Predictive biomarkers of readmission would facilitate stratification strategies and individualized prognosis. Therefore, this study aimed to investigate the utility of type 2 biomarkers (eosinophils, periostin, and YKL-40) and a type 1 biomarker (CXCL9) in predicting readmission events in patients with AECOPD.

Methods

This is a prospective observational study design. Blood levels of eosinophils, periostin, YKL-40, and CXCL9 were measured at admission. The clinical outcomes were 12-month COPD-related readmission, time to COPD-related readmission, and number of 12-month COPD-related readmissions. These outcomes were analyzed using logistic and Cox regression models and Spearman's rank test.

Results

A total of 123 patients were included, of whom 51 had experienced at least one readmission for AECOPD. High levels of eosinophils (≥200 cells/μL or 2% of the total white blood cell count, adjusted odds ratio [aOR] =3.138, P=0.009) and YKL-40 (≥14.5 ng/mL, aOR =2.840, P=0.015), as well as low CXCL9 levels (≤30.1 ng/mL, aOR =2.551, P=0.028), were associated with an increased COPD-related readmission. The highest relative readmission rate was observed in patients with both high eosinophil and YKL-40 levels. Moreover, high eosinophil and YKL-40 levels were associated with a shorter time to first COPD-related readmission and an increased number of 12-month COPD-related readmissions.

Conclusion

High blood eosinophil and YKL-40 levels, as well as low CXCL9 levels, have predictive utility for the 12-month COPD-related readmission rate. Using eosinophils and YKL-40 together allows more precise identification of patients at high risk of COPD-related readmission.

Glycated Hemoglobin (HbA1c) as a Predictor of Outcomes during Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Systemic inflammation may be the common denominator between COPD and type 2 diabetes and may explain the correlation in both diseases' development and progress. The aim of this prospective observational study is to examine the prognostic value of glycated hemoglobin levels (HbA1c) and HbA1c-adjusted glycemic variables (glycemic gap, stress hyperglycemia ratio και modified stress hyperglycemia ratio) in an acute exacerbation of COPD (AECOPD) as well as in COPD disease's morbidity and mortality during the following year. We evaluated patients hospitalized only for COPD exacerbations. Levels of HbA1c and HbA1c-adjusted glycemic variables were recorded upon admission. The study outcomes included duration of hospital stay, need for mechanical ventilation and exacerbation outcome. All subjects were followed up for one year. A total of 156 patients were included in the study (74.4% men, age [mean ± SD] 72 ± 7 years). Patients (21.8%) had type 2 diabetes and 67.9% of patients were receiving ICS treatment. The median value of HbA1c was 5.9 (IQR: 5.4, 6.5). Necessity for mechanical ventilation was significantly higher for patients with lower values of HbA1c [median: 5.3 (IQR 5.02, 6.3) vs. 5.9 (IQR 5.5, 6.5), p = .038]. However, duration of hospitalization, death during hospitalization as well as the number of new exacerbation events, time to next exacerbation and mortality during the following year did not differ significantly. Moreover, none of the HbA1c-adjusted glycemic variables examined, demonstrated any statistical significance. In conclusion neither the preceding nor the present glycemic state exhibit a predictive value regarding short- or long-term outcomes of an AECOPD.

Review on the correlation between chronic obstructive pulmonary disease and eosinophil in peripheral blood

Chronic obstructive pulmonary disease (COPD) is an irreversible disease characterized by the limitation of continuous airflow. Eosinophil (EOS) in peripheral blood plays a key role in the acute exacerbation of COPD. Eosinophil-increased COPD has become an important variant of COPD and the focus of individualized treatment of COPD. Numerous studies have shown that an increased eosinophil count or an increased percentage in the peripheral blood closely correlates to the acute exacerbation and prognosis of COPD. Therefore, this study intends to review the progress of domestic and foreign research on the correlation between COPD and EOS.

The association between eosinophilic exacerbation and eosinophilic levels in stable COPD

Background

Blood eosinophil count may predict treatment response in patients with chronic obstructive pulmonary disease (COPD) during acute exacerbations (AE). However, the ability and thresholds of blood eosinophil counts in stable status to predict eosinophilic AECOPD have not been completely investigated.

Methods

This was a retrospective multicenter study performed January 2010 to December 2014. COPD subjects hospitalized with exacerbations, were included. Blood samples were obtained at the time of AE and stable disease at outpatient clinic before or after admission. We identified a blood eosinophil count cut-off point at stable COPD, either taken as a percentage or as absolute value, for identification of eosinophilic exacerbation.

Results

There was significant positive correlation of eosinophil counts between stable COPD and AECOPD. The best cut-off value of blood eosinophil count in stable status for the prediction of eosinophilic COPD exacerbation based on blood eosinophil count ≥ 2% was 300 cells/µL (area under the ROC curve [AUC] 0.614, P = 0.001, 39% sensitivity, 83.8% specificity). When the eosinophilic COPD exacerbation was based on blood eosinophil count ≥ 300 cells/µL, the best cut-off value of blood eosinophil count in stable status for the prediction of eosinophilic COPD exacerbation was also 300 cells/uL (AUC 0.634, P = 0.046, 45.8% sensitivity, 80.9% specificity).

Conclusions

We demonstrated association between blood eosinophil counts at stable COPD and those with AECOPD. The thresholds of blood counts at stable COPD to predict eosinophilic exacerbations was 300 cells/µL. Further and prospective studies in other populations should validate our results.

Blood eosinophils on hospital admission for COPD exacerbation do not predict the recurrence of moderate and severe relapses

Background and objective

The relationship between hospitalisation with an eosinophilic acute exacerbation of COPD (AE-COPD) and future relapses is unclear. We aimed to explore this association by following 152 patients for 12 months after hospital discharge or until their first moderate or severe flare-up.

Methods

Patients hospitalised with AE-COPD were divided into eosinophilic and non-eosinophilic groups based on full blood count results on admission. All patients were treated with a course of systemic corticosteroid. The Cox proportional hazards model was used to study the association with the time to first re-exacerbation; a generalised linear regression model was applied to identify clinical variables related to the recurrence of relapses.

Results

We did not find a difference in the time to the next moderate or severe exacerbation between the eosinophilic (≥2% of total leukocytes and/or ≥200 eosinophils·µL⁻¹, n=51, median (interquartile range): 21 (10–36) weeks) and non-eosinophilic groups (n=101, 17 (9–36) weeks, log-rank test: p=0.63). No association was found when other cut-off values (≥3% of total leukocytes and/or ≥300 eosinophils·µL⁻¹) were used for the eosinophilic phenotype. However, the higher number of past severe exacerbations, a lower forced expiratory volume in 1 s (FEV₁) at discharge and higher pack-years were related to shorter exacerbation-free time. According to a subgroup analysis (n=73), 48.1% of patients with initial eosinophilic exacerbations had non-eosinophilic relapses on readmission.

Conclusions

Our data do not support an increased risk of earlier recurring moderate or severe relapses in patients hospitalised with eosinophilic exacerbations of COPD. Eosinophilic severe exacerbations present a variable phenotype.

Shorter time to the next relapse after severe COPD exacerbation is related to the number of prior hospitalisations, smoking history and more severe airflow limitation. Blood eosinophils are not predictive of the recurrence of moderate or severe relapses.https://bit.ly/2VkbBNC

Protocol for an observational study to identify potential predictors of an acute exacerbation in patients with chronic obstructive pulmonary disease (the PACE Study)

INTRODUCTION

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are the most critical events for patients with COPD that have a negative impact on patients' quality of life, accelerate disease progression, and can result in hospital admissions and death. Although there is no distinct definition or detailed knowledge about AECOPD, it is commonly used as primary outcome in clinical studies. Furthermore, it may be difficult in clinical practice to differentiate the worsening of symptoms due to an AECOPD or to the development of heart failure. Therefore, it is of major clinical importance to investigate the underlying pathophysiology, and if possible, predictors of an AECOPD and thus to identify patients who are at high risk for developing an acute exacerbation.

METHODS AND ANALYSIS

In total, 355 patients with COPD will be included prospectively to this study during a 3-week inpatient pulmonary rehabilitation programme at the Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee (Germany). All patients will be closely monitored from admission to discharge. Lung function, exercise tests, clinical parameters, quality of life, physical activity and symptoms will be recorded, and blood samples and exhaled air will be collected. If a patient develops an AECOPD, there will be additional comprehensive diagnostic assessments to differentiate between cardiac, pulmonary or cardiopulmonary causes of worsening. Follow-up measures will be performed at 6, 12 and 24 months.Exploratory data analyses methods will be used for the primary research question (screening and identification of possible factors to predict an AECOPD). Regression analyses and a generalised linear model with a binomial outcome (AECOPD) will be applied to test if predictors are significant.

ETHICS AND DISSEMINATION

This study has been approved by the Ethical Committee of the Philipps University Marburg, Germany (No. 61/19). The results will be presented in conferences and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT04140097.

Using Blood Eosinophil Count as a Biomarker to Guide Corticosteroid Treatment for Chronic Obstructive Pulmonary Disease

Treating patients hospitalised with acute exacerbations of chronic obstructive pulmonary disease (COPD) usually involves administering systemic corticosteroids. The many unwanted side effects associated with this treatment have led to increased interest in minimising the accumulated corticosteroid dose necessary to treat exacerbations. Studies have shown that short-term treatment with corticosteroids is preferred, and recent trials have shown that biomarkers can be used to further reduce exposure to corticosteroids. Interestingly, high eosinophil counts in patients with acute exacerbations of COPD are indicative of an eosinophilic phenotype with a distinct response to treatment with corticosteroids. In addition, post-hoc analysis of randomised control trials have shown that higher blood eosinophil counts at the start of the study predict a greater response to inhaled corticosteroids in stable COPD. In this review, we examine the studies on this topic, describe how blood eosinophil cell count may be used as a biomarker to guide treatment with corticosteroids, and identify some relevant challenges.

Eosinophilic inflammation in COPD: from an inflammatory marker to a treatable trait

The heterogeneity of chronic obstructive pulmonary disease (COPD) creates many diagnostic, prognostic, treatment and management challenges, as the pathogenesis of COPD is highly complex and the underlying cellular and molecular mechanisms remain poorly understood. A reliable, easy-to-measure, clinically relevant biomarker would be invaluable for improving outcomes for patients. International and national guidance for COPD suggests using blood eosinophil counts as a biomarker to help estimate likely responsiveness to inhaled corticosteroids (ICS) and, potentially, to aid effective management strategies. However, with the mechanism underlying the association between higher eosinophil levels and ICS effect unknown, use of the blood eosinophil count in COPD continues to be widely debated by the respiratory community.Two international meetings involving respiratory medicine specialists, immunologists and primary and secondary care clinicians were held in November 2018 and March 2019, facilitated and funded by GlaxoSmithKline plc. The aims of these meetings were to explore the role of eosinophils in the disease processes of COPD and as prognostic and diagnostic markers, and to identify areas of deficient knowledge that warrant further research. The consensus views of the attendees on key topics, contextualised with current literature, are summarised in this review article, with the aim of aiding ongoing research into the disease processes of COPD and the development of biomarkers to aid clinical management.Under certain conditions, eosinophils can be recruited to the lung, and increasing evidence supports a role for eosinophilic inflammation in some patients with COPD. Infiltration of eosinophils across the bronchial vascular epithelium into the airways is promoted by the actions of immunoregulatory cells, cytokines and chemokines, where eosinophil-mediated inflammation is driven by the release of proinflammatory mediators.Multiple studies and two meta-analyses suggest peripheral blood eosinophils may correlate positively with an increased likelihood of exacerbation reduction benefits of ICS in COPD. The studies, however, vary in design and duration and by which eosinophil levels are viewed as predictive of an ICS response. Generally, the response was seen when eosinophil levels were 100-300 cells/µL (or higher), levels which are traditionally viewed within the normal range. Some success with interleukin-5-targeted therapy suggests that the eosinophilic phenotype may be a treatable trait.The use of biomarkers could help to stratify treatment for COPD-the goal of which is to improve patient outcomes. Some evidence supports eosinophils as a potential biomarker of a treatable trait in COPD, though it is still lacking and research is ongoing. A unified consensus and a practical, accessible and affordable method of utilising any biomarker for COPD was thought to be of most importance. Challenges around its utilisation may include presenting a clear and pragmatic rationale for biomarker-driven therapy, guidance on ICS withdrawal between primary and secondary care and a lack of financial incentives supporting broad application in clinical practice. Future treatments should, perhaps, be more targeted rather than assuming the primary disease label (COPD or asthma) will define treatment response.

Blood Eosinophils and Clinical Outcome of Acute Exacerbations of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Numerous studies have shown the association between eosinophilia and clinical outcomes of patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). But the evidences are lack of consensus.

OBJECTIVE

The aim of this meta-analysis was to conduct a pooled analysis of outcome comparing eosinophilic (EOS) AECOPD and non-EOS AECOPD patients.

METHODS

We included PubMed, EMBASE, Web of Science, and Cochrane databases up to 2020 to retrieve articles. Randomized controlled trials and quasi-experimental studies about patients with and without EOS AECOPD in terms of in-hospital mortality, length of hospital stay, comorbidities, forced expiratory volume in 1 s (FEV1), gender, and BMI were included preclinical studies, review articles, editorials, commentaries, conference abstracts, and book chapters were excluded. The methodologic assessment of studies was performed with the Newcastle-Ottawa Scale and Cochran scale. Comprehensive Rev Man 5 was used for the statistical analysis.

RESULTS

Twenty-one studies with 18,041 patients fulfilled the inclusion criteria and were used in this meta-analysis. Comparing to the non-EOS group, those with EOS AECOPD patients had a lower risk for in-hospital mortality (odds ratio (OR) = 0.59, 95% confidence interval [CI] 0.36-0.95, p = 0.03), shorter length of hospital stay (OR = -0.72, 95% CI -1.44 to -0.00, p = 0.05), better FEV1 (mean difference = 0.14, 95% CI 0.08-0.20, p < 0.00001), and a lower risk of arrhythmias (OR = 1.50, 95% CI 1.01-2.21, p = 0.04). In addition, the non-EOS group had a higher percentage of male (OR = 1.34, 95% CI 1.15-1.56, p = 0.0002) than EOS group. The rate of steroid use (OR = 0.82, 95% CI 0.47-1.42, p = 0.48) and BMI (mean difference = 0.43, 95% CI -0.18 to 1.05, p = 0.17] had no difference between 2 groups.

CONCLUSION

The results of our meta-analysis suggest that EOS AECOPD patients have a better clinical outcome than non-EOS AECOPD patients in terms of length of hospital stay, in-hospital mortality, FEV1, and risk of arrhythmias. In addition, the non-EOS AECOPD patients have higher percentage of male than EOS AECOPD patients.

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.

Richness of sputum microbiome in acute exacerbations of eosinophilic chronic obstructive pulmonary disease

BACKGROUND

The eosinophilic chronic obstructive pulmonary disease (COPD) is known to be more sensitive to corticosteroid. The sputum microbiome has been shown to affect COPD prognosis, but its role in acute exacerbations of eosinophilic COPD is unclear. This study aimed to investigate the dynamic changes of the airway microbiome in patients with acute exacerbations of eosinophilic COPD.

METHODS

Fifty-seven patients with acute exacerbations of COPD from the First Affiliated Hospital of Guangxi Medical University between June 2017 and June 2018 were divided into two groups. Patients with eosinophils ≥300 cells/μL in the peripheral venous blood were assigned to the eosinophilic group (Eos) and the rest to the non-eosinophilic group (Noneos). All patients received similar treatment including inhaled budesonide according to the guidelines. The induced sputum microbiome was analyzed on the 1st and 7th day of treatment using the 16S ribosomal RNA (rRNA) method. The levels of interleukin (IL)-6 and IL-8 were measured in the plasma and the sensitivity to corticosteroids was determined in isolated peripheral blood mononuclear cells. Quantitative data were compared between the two groups using the independent samples t test or Mann-Whitney U test. Categorical data were evaluated using Chi-squared test or Fisher's exact test.

RESULTS

Twenty-six patients were classified into Eos group and 31 patients were classified into Noneos group. Prior to treatment, the alpha diversity (Shannon index) (2.65 ± 0.63 vs. 2.56 ± 0.54, t = 0.328, P = 0.747) and the structure of the sputum microbiome were similar in the Eos group and the Noneos group. After 7 days of treatment, alpha diversity increased in both groups, while the microbiome richness (Ace index) was significantly lower in the Eos group (561.87 ± 109.13 vs. 767.88 ± 148.48, t = -3.535, P = 0.002). At the same time, IL-6 (12.09 ± 2.85 pg/mL vs. 15.54 ± 2.45 pg/mL, t = -4.913, P < 0.001) and IL-8 (63.64 ± 21.69 pg/mL vs. 78.97 ± 17.13 pg/mL, t = -2.981, P = 0.004) decreased more significantly in the Eos group, and the percentages of inhibition of IL-8 at dexamethasone concentrations 10 to 10 mol/L were significantly higher in the Eos group than those in the Noneos group (all P < 0.05).

CONCLUSIONS

The induced sputum microbiome richness decreased more significantly following treatment in the Eos patients compared to the Noneos patients. The lower plasma inflammatory factor levels and the higher percentage of inhibition of IL-8 might be due to higher corticosteroid sensitivity in Eos patients.

Blood Eosinophil and Risk of Exacerbation in Chronic Obstructive Pulmonary Disease Patients: A Retrospective Cohort Analysis

Purpose

Blood eosinophil is a readily available biomarker to reflect the eosinophilic inflammation in chronic obstructive pulmonary disease (COPD) patients, yet its association with exacerbation is inconclusive. It is uncertain which measurement, eosinophil percentage or absolute eosinophil count, should be used and what is the optimal cutoff for exacerbation prediction.

Patients and Methods

A total of 247 COPD patients were included in this retrospective cohort study. Blood eosinophil during stable disease state, baseline demographics, and clinical characteristics in 12 months after the index complete blood count (CBC) were recorded. Exacerbation frequencies were compared between patients with high and low blood eosinophil percentage using 2% as cut-off. Logistic regression and receiver operating characteristics (ROC) curve analyses were conducted.

Results

Patients with blood eosinophil ≥2% were associated with more frequent exacerbations than patients with eosinophil <2% in the 12 months after the index CBC (mean exacerbation 1.07 vs 0.34, p < 0.001). Higher blood eosinophil percentage conferred a higher risk of exacerbation. Adjusted odds ratio for exacerbation in 12 months after the index CBC for blood eosinophil ≥2% was 2.98 (95% confidence interval = 1.42–6.25). The area under the ROC curve of eosinophil percentage was significantly higher than that of absolute eosinophil count (0.678 vs 0.640, p = 0.010). The optimal cutoff of blood eosinophil percentage for exacerbation prediction was 2.8%.

Conclusion

Blood eosinophilia was associated with higher exacerbation risk in COPD patients. Further studies are required to elucidate the mechanism of eosinophilic inflammation in COPD and determine the optimal treatment strategy to reduce exacerbations.