Blood eosinophils as a biomarker of future COPD exacerbation risk: pooled data from 11 clinical trials

Blood eosinophils levels in a Colombian cohort of biomass-and tobacco-related COPD patients

Introduction

Chronic obstructive pulmonary disease (COPD) is a major cause of illness and death among adults. In 2019, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) strategy incorporated blood eosinophils as a biomarker to identify patients at increased risk of exacerbations which, with the history of exacerbations during the previous year, allows identification of patients who would benefit from anti-inflammatory treatment to reduce the risk of future exacerbations. The aim of this study was to describe demographic and clinical characteristics, eosinophil counts, and exacerbations in a cohort of COPD patients stratified by clinical phenotypes (non-exacerbator, frequent exacerbator, asthma-COPD overlap) in a Colombian cohort at 2600 meters above sea level.

Methods

A descriptive analysis of a historical cohort of patients with a confirmed diagnosis of moderate to severe COPD (FEV1/FVC < 0.7 and at least one risk factor for COPD) from two specialized centers with comprehensive disease management programs was performed from January 2015 to March 2019. Data were extracted from medical records 1 year before and after the index date.

Results

200 patients were included (GOLD B: 156, GOLD E: 44; 2023 GOLD classification); mean age was 77.9 (SD 7.9) years; 48% were women, and 52% had biomass exposure as a COPD risk factor. The mean FEV1/FVC was 53.4% (SD 9.8), with an FEV1 of 52.7% (20.7). No differences were observed between clinical phenotypes in terms of airflow limitation. The geometric mean of absolute blood eosinophils was 197.58 (SD 2.09) cells/μL (range 0 to 3,020). Mean blood eosinophil count was higher in patients with smoking history and frequent exacerbators. At least one moderate and one severe exacerbation occurred in the previous year in 44 and 8% of patients, respectively; during the follow-up year 152 exacerbations were registered, 122 (80%) moderate and 30 (20%) severe. The highest rate of exacerbations in the follow-up year occurred in the subgroup of patients with the frequent exacerbator phenotype and eosinophils ≥300 cells/μL.

Discussion

In this cohort, the frequency of biomass exposure as a risk factor is considerable. High blood eosinophil count was related to smoking, and to the frequent exacerbator phenotype.

Type 2 airway inflammation in COPD

Globally, nearly 400 million persons have COPD, and COPD is one of the leading causes of hospitalisation and mortality across the world. While it has been long-recognised that COPD is an inflammatory lung disease, dissimilar to asthma, type 2 inflammation was thought to play a minor role. However, recent studies suggest that in approximately one third of patients with COPD, type 2 inflammation may be an important driver of disease and a potential therapeutic target. Importantly, the immune cells and molecules involved in COPD-related type 2 immunity may be significantly different from those observed in severe asthma. Here, we identify the important molecules and effector immune cells involved in type 2 airway inflammation in COPD, discuss the recent therapeutic trial results of biologicals that have targeted these pathways and explore the future of therapeutic development of type 2 immune modulators in COPD.

Clinical utilization of airway inflammatory biomarkers in the prediction and monitoring of clinical outcomes in patients with chronic obstructive pulmonary disease

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) accounts for 545 million people living with chronic respiratory disorders and is the third leading cause of morbidity and mortality around the world. COPD is a progressive disease, characterized by episodes of acute worsening of symptoms such as cough, dyspnea, and sputum production.

AREAS COVERED

Airway inflammation is a prominent feature of COPD. Chronic airway inflammation results in airway structural remodeling and emphysema. Persistent airway inflammation is a treatable trait of COPD and plays a significant role in disease development and progression. In this review, the authors summarize the current and emerging biomarkers that reveal the heterogeneity of airway inflammation subtypes, clinical outcomes, and therapeutic response in COPD.

EXPERT OPINION

Airway inflammation can be broadly categorized as eosinophilic (type 2 inflammation) and non-eosinophilic (non-type 2 inflammation) in COPD. Currently, blood eosinophil counts are incorporated in clinical practice guidelines to identify COPD patients who are at a higher risk of exacerbations and lung function decline, and who are likely to respond to inhaled corticosteroids. As new therapeutics are being developed for the chronic management of COPD, it is essential to identify biomarkers that will predict treatment response.

Endotypes of Paediatric Cough-Do They Exist and Finding New Techniques to Improve Clinical Outcomes

Chronic cough is a common symptom of many childhood lung conditions. Given the phenotypic heterogeneity of chronic cough, better characterization through endotyping is required to provide diagnostic certainty, precision therapies and to identify pathobiological mechanisms. This review summarizes recent endotype discoveries in airway diseases, particularly in relation to children, and describes the multi-omic approaches that are required to define endotypes. Potential biospecimens that may contribute to endotype and biomarker discoveries are also discussed. Identifying endotypes of chronic cough can likely provide personalized medicine and contribute to improved clinical outcomes for children.

Predictive Role of White Blood Cell Differential Count for the Development of Acute Exacerbation in Korean Chronic Obstructive Pulmonary Disease

Purpose

Chronic obstructive pulmonary disease (COPD) is a respiratory disease characterized by chronic inflammation. Acute exacerbation of COPD (AECOPD) manifests as acute worsening of respiratory symptoms and is associated with high morbidity and mortality. The aim of the present study was to evaluate the predictive value of white blood count (WBC) and its derived inflammatory biomarkers for AECOPD.

Methods

From the Korean COPD Subgroup Study cohort, a prospective and multicenter observational study, 826 patients who had baseline complete blood count (CBC) and 3-year AECOPD data were included. Follow-up CBC data at 1 (n = 385), 2 (n = 294), and 3 (n = 231) years were collected for available patients. The primary outcome was the occurrence of AECOPD at 3 years. The risk of AECOPD was evaluated using a binary logistic analysis.

Results

The cumulative incidences of 12-, 24-, and 36-month AECOPD were 47.6%, 60.5%, and 67.6%, respectively. Patients with AECOPD at 3 years had higher baseline WBC counts, neutrophil counts, neutrophil/lymphocyte ratio (NLR), and neutrophil/monocyte ratio than those without AECOPD. Higher WBC count, neutrophil count, and NLR were associated with the 3-year occurrence of AECOPD in the univariate analysis, but only the higher neutrophil count was a significant risk factor (odds ratio [OR] = 1.468; 95% confidence interval [CI]: 1.024-2.104) in the covariates-adjusted analysis. In the analysis of changes in inflammatory parameters, a decrease in the platelet count (OR = 0.502; 95% CI: 0.280-0.902) and NLR (OR = 0.535; 95% CI: 0.294-0.974) at 2 years and an increase in the eosinophil count (OR = 2.130; 95% CI: 1.027-4.416) at 3 years were significantly associated with AECOPD in the adjusted analysis.

Conclusion

Our data suggest that a high baseline WBC count, particularly neutrophil count, was associated with a higher incidence of long-term AECOPD.

Rational use of inhaled corticosteroids for the treatment of COPD

Inhaled corticosteroids (ICS) are the mainstay of treatment for asthma, but their role in chronic obstructive pulmonary disease (COPD) is debated. Recent randomised controlled trials (RCTs) conducted in patients with COPD and frequent or severe exacerbations demonstrated a significant reduction (~25%) in exacerbations with ICS in combination with dual bronchodilator therapy (triple therapy). However, the suggestion of a mortality benefit associated with ICS in these trials has since been rejected by the European Medicines Agency and US Food and Drug Administration. Observational evidence from routine clinical practice demonstrates that dual bronchodilation is associated with better clinical outcomes than triple therapy in a broad population of patients with COPD and infrequent exacerbations. This reinforces guideline recommendations that ICS-containing maintenance therapy should be reserved for patients with frequent or severe exacerbations and high blood eosinophils (~10% of the COPD population), or those with concomitant asthma. However, data from routine clinical practice indicate ICS overuse, with up to 50-80% of patients prescribed ICS. Prescription of ICS in patients not fulfilling guideline criteria puts patients at unnecessary risk of pneumonia and other long-term adverse events and also has cost implications, without any clear benefit in disease control. In this article, we review the benefits and risks of ICS use in COPD, drawing on evidence from RCTs and observational studies conducted in primary care. We also provide a practical guide to prescribing ICS, based on the latest global treatment guidelines, to help primary care providers identify patients for whom the benefits of ICS outweigh the risks.

EVELUT®: A Real-World, Observational Study Assessing Dyspnoea and Symptom Burden in COPD Patients Switched from LABA/ICS to LAMA/LABA or LAMA/LABA/ICS

INTRODUCTION

The Global Initiative for Chronic Obstructive Lung Disease (GOLD 2023) no longer recommends a long-acting β2-agonist (LABA) plus inhaled corticosteroid (ICS) combination for the treatment of chronic obstructive pulmonary disease (COPD). In patients treated with LABA/ICS, who continue to experience symptoms without frequent or severe exacerbations, GOLD now recommends switching to long-acting muscarinic antagonist (LAMA)/LABA instead of escalating to triple therapy (TT; LAMA/LABA/ICS), which previously was also a recommended option. EVELUT®, a real-life, observational study, compared these two treatment strategies in terms of symptom relief and health status improvement.

METHODS

Patients with symptomatic COPD at low exacerbation risk (GOLD B) were switched, at their physicians' discretion, from LABA/ICS to either fixed-dose LAMA/LABA (tiotropium/olodaterol, Respimat® [Tio/Olo]) or fixed or free TT. Primary endpoints were change in modified Medical Research Council (mMRC) and COPD Assessment Test™ (CAT™) scores after 12 weeks.

RESULTS

The safety set contained 463 patients (Tio/Olo, n = 329; TT, n = 134). In a propensity score-matched set (Tio/Olo, n = 121; TT, n = 121), improvement in mMRC score was similar in patients on Tio/Olo (-0.23; 95% confidence interval [CI] -0.11, -0.36) and TT (-0.25; 95% CI -0.13, -0.38). Improvement in total CAT score was slightly larger in patients on Tio/Olo (-3.45; 95% CI -2.45, -4.45) versus TT (-2.51; 95% CI -1.62, -3.40). In both groups, Physician's Global Evaluation scores increased, with 69-89% of patients satisfied with their treatment overall. Marginally more patients on Tio/Olo responded to treatment versus TT (Δ mMRC score ≥ 1; 25% vs. 22%; Δ CAT score ≥ 2, 68% vs. 56%).

CONCLUSION

In patients with symptomatic COPD at low exacerbation risk, treatment can be switched from LABA/ICS to LAMA/LABA without compromising clinical benefit, compared with escalating to LAMA/LABA/ICS. Switching from LABA/ICS to LAMA/LABA can provide symptom relief and improve health status without exposure to the risks associated with ICS.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT03954132.

Blood Eosinophil Count as a Predictive Biomarker of Chronic Obstructive Pulmonary Disease Exacerbation in a Real-World Setting

Introduction

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death, and COPD exacerbation worsens the prognosis. Eosinophilic airway inflammation is a COPD phenotype that causes COPD exacerbation and is correlated with peripheral blood eosinophil count. We analyzed real-world data of COPD patients to assess the risk factors of COPD exacerbation focusing on blood eosinophils.

Materials and Methods

Patients with COPD who visited our hospital between January 1, 2018, and December 31, 2018, were recruited, and their background information, spirometry data, laboratory test results, and moderate-to-severe exacerbation events during the one-year follow-up period were collected from the electronic medical records and analyzed. The COPD exacerbation risk factors were assessed using univariate and multivariate logistic regression analyses.

Results

Twenty-two of 271 (8.1%) patients experienced moderate-to-severe exacerbation. Patients with exacerbation showed worse pulmonary function, and we found that a high blood eosinophil count (≥350 cells/μL; p=0.014), low % FEV1 (<50%; p=0.002), increase in white blood cell (≥9000 cells/μL; p=0.039), and use of home oxygen therapy (p=0.005) were risk factors for future exacerbations. We also found a strong correlation between eosinophil count cut-offs and exacerbation risk (r = 0.89, p < 0.001). On the other hand, there was no relation between exacerbation risk and inhalation therapy for COPD.

Conclusion

In a real-world setting, peripheral blood eosinophil count could be a predictor of future COPD exacerbation.

In 'real world' patients with COPD, exacerbation history, and not blood eosinophils, is the most reliable predictor of future exacerbations

INTRODUCTION

There is an interest in the role of blood eosinophils for predicting inhaled corticosteroid (ICS) response in chronic obstructive pulmonary disease (COPD). Most data are from interventional clinical studies; data from unselected real-world populations may help better inform treatment decisions. DACCORD is a non-interventional real-world study. Cohort 3 recruited patients with COPD who had received triple therapy for ≥ 6 months; prior to entry patients either continued triple therapy, or switched to a long-acting muscarinic antagonist/long-acting beta₂-agonist (LABA/LAMA), and were followed for 12 months.

METHODS

For these post-hoc analyses, patients were divided into four groups based on exacerbation history and baseline blood eosinophil count (< 100 vs. > 300 cells/µL). Exacerbation rates were calculated overall and for the two treatments.

RESULTS

Among the 430 patients in the current analyses, the largest groups had low exacerbation history with high (44.2%) or low eosinophils (36.7%). Most patients did not exacerbate during follow-up (68.8% overall; 83.2% and 63.7% with LABA/LAMA and triple therapy). The highest exacerbation rates were in groups with high exacerbation history, differing significantly in the overall analyses from those with low exacerbation history (matched by eosinophil count); rates did not differ when grouped by eosinophil count (matched by exacerbation history).

CONCLUSIONS

Although most patients in these analyses did not exacerbate during follow-up, whereas exacerbation history is a predictor of future exacerbations, blood eosinophil count is not. This suggests that although eosinophil count may help to guide ICS initiation, this is less of a consideration when 'stepping-down' from triple therapy to a LABA/LAMA.

Circulating eosinophil levels and lung function decline in stable chronic obstructive pulmonary disease: a retrospective longitudinal study

OBJECTIVE

Whether blood eosinophils (bEOS) in chronic obstructive pulmonary disease (COPD) are associated with disease progression is a topic of debate. We aimed to evaluate whether the differential white blood cell (WBC) count, symptoms and treatment may predict lung function decline and exacerbations in COPD patients.

METHODS

We retrospectively examined stable COPD patients with a minimum follow-up of 3 years at our outpatients' clinic. We collected information about lung volumes (FEV1, FVC), the total and differential WBC count, acute exacerbations of COPD (number in the 12 months before the beginning of the study=AE-COPD-B, and during the follow-up=AE-COPD-F), smoking status and treatment. FEV1 decline and AE-COPD-F were described by using a generalized linear model and a 2-level random intercept negative binomial regression, respectively. The models included eosinophil and neutrophil counts as potential predictors and were adjusted by sex, age, smoking status, AE-COPD-B, treatment with bronchodilators and inhaled corticosteroids (ICS).

RESULTS

Sixty-eight patients were considered, 36 bEOS- (<170 cells/μL, the median value) and 32 bEOS+ (≥170 cells/μL). ∆FEV1 was higher in bEOS+ than bEOS- (34.86 mL/yr vs 4.49 mL/yr, p=0.029). After adjusting for potential confounders, the eosinophil count was positively (β=19.4; CI 95% 2.8, 36.1; p=0.022) and ICS negatively (β=-57.7; CI 95% -91.5,-23.9; p=0.001) associated with lung function decline. bEOS were not found to be associated with the number of AE-COPD-F.

CONCLUSION

In stable COPD patients, a higher level of blood eosinophils (albeit in the normal range) predicts a greater FEV1 decline, while ICS are associated with a slower progression of airflow obstruction.

Blood Eosinophil Endotypes across Asthma and Chronic Obstructive Pulmonary Disease (COPD)

Background

Eosinophils were common inflammatory cells involved in the occurrence and development of various inflammatory diseases. Multiple recent studies have pointed to the increasingly important role of eosinophils in respiratory diseases. This article aims to compare the expression differences of blood eosinophil counts between asthma, chronic obstructive pulmonary disease (COPD), and asthma-COPD overlap (ACO).

Methods

Patients with asthma, COPD, and ACO who were seen in the First Affiliated Hospital of Guangzhou Medical University from January 2012 to June 2019 were included. We collected information such as age, gender, diagnosis, the eosinophil counts from the medical records. Moreover, the levels of 10 cytokines in the plasma of each group were detected by using the Meso Scale Discovery method.

Results

We included 9787 patients with asthma, 15806 patients with COPD, and 831 ACO patients. From our results, it can be first found that eosinophil levels were age-related in the three diseases (asthma and ACO: p < 0.001; COPD: P = 0.001); in asthma and COPD, the number of eosinophils in males was more significant than that in females (asthma: p < 0.001; COPD: p = 0.012). Second, asthma patients had higher blood eosinophil counts than those with COPD and ACO (p < 0.001). Moreover, we found out that eosinophil levels were highly expressed in the stable group of all three diseases. Finally, we found that most cytokines in ACO patients showed a downward trend when the level of eosinophils was low, whereas the results were reversed in asthma patients; 7 cytokines had similar trends in COPD and ACO patients.

Conclusions

In conclusion, eosinophils have their own unique endotypes in asthma, COPD, and ACO patients, which were reflected in the fluctuation of their levels and changes in cytokine secretion.

Towards the elimination of chronic obstructive pulmonary disease: a Lancet Commission

Despite substantial progress in reducing the global impact of many non-communicable diseases, including heart disease and cancer, morbidity and mortality due to chronic respiratory disease continues to increase. This increase is driven primarily by the growing burden of chronic obstructive pulmonary disease (COPD), and has occurred despite the identification of cigarette smoking as the major risk factor for the disease more than 50 years ago. Many factors have contributed to what must now be considered a public health emergency: failure to limit the sale and consumption of tobacco products, unchecked exposure to environmental pollutants across the life course, and the ageing of the global population (partly as a result of improved outcomes for other conditions). Additionally, despite the heterogeneity of COPD, diagnostic approaches have not changed in decades and rely almost exclusively on post-bronchodilator spirometry, which is insensitive for early pathological changes, underused, often misinterpreted, and not predictive of symptoms. Furthermore, guidelines recommend only simplistic disease classification strategies, resulting in the same therapeutic approach for patients with widely differing conditions that are almost certainly driven by variable pathophysiological mechanisms. And, compared with other diseases with similar or less morbidity and mortality, the investment of financial and intellectual resources from both the public and private sector to advance understanding of COPD, reduce exposure to known risks, and develop new therapeutics has been woefully inadequate.

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.

Defining Asthma-Chronic Obstructive Pulmonary Disease Overlap

Much interest has been given to the asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) in the past 2 decades, but the condition is still ill-defined. There is general agreement that a patient with longstanding asthma who develops fixed airflow obstruction after years of smoking has ACO although defining asthma in the face of COPD can be challenging. Many features of asthma are also found in patients with COPD without indicating an overlap and no consensus exists on which characteristics should be included in the definition of ACO. Nevertheless, some guidance has been issued to help clinicians and researchers to make a diagnosis of ACO and these will be reviewed here.

Blood Eosinophils and Chronic Obstructive Pulmonary Disease: A GOLD Science Committee 2022 Review

COPD is a heterogeneous condition. Some patients benefit from treatment with inhaled corticosteroids (ICS) but this requires a precision medicine approach, based on clinical characteristics (phenotyping) and biological information (endotyping) in order to select patients most likely to benefit. The GOLD 2019 report recommended using exacerbation history combined with blood eosinophil counts (BEC) to identify such patients. Importantly, the relationship between BEC and ICS effects is continuous; no / small effects are observed at lower BEC, with increasing effects at higher BEC. The GOLD 2022 report has added additional evidence and recommendations concerning the use of BEC in COPD in clinical practice. Notably, associations have been demonstrated in COPD patients between higher BEC and increased levels of type-2 inflammation in the lungs. These differences in type-2 inflammation can explain the differential ICS response according to BEC. Additionally, lower BEC are associated with greater presence of proteobacteria, notably haemophilus, and increased bacterial infections and pneumonia risk. These observations support management strategies that use BEC to help identify subgroups with increased ICS response (higher BEC) or increased risk of bacterial infection (lower BEC). Recent studies in younger individuals without COPD have also shown that higher BEC are associated with increased risk of FEV1 decline and the development of COPD. Here we discuss and summarise the GOLD 2022 recommendations concerning the use of BEC as a biomarker that can facilitate a personalised management approach in COPD.

PREVALENCE AND IMPACT OF COMORBIDITIES IN INDIVIDUALS WITH COPD: A SYSTEMATIC REVIEW

This study aimed to describe the prevalence of comorbidities associated with chronic obstructive pulmonary disease (COPD) and their relation with relevant outcomes. A systematic review based on the PRISMA methodology was performed from January 2020 until July 2021. The MEDLINE, Lilacs, and Scielo databases were searched to identify studies related to COPD and its comorbidities. Observational studies on the prevalence of comorbidities in COPD patients and costs with health estimates, reduced quality of life, and mortality were included. Studies that were restricted to one or more COPD pain assessments and only specific comorbidities such as osteoporosis, bronchitis, and asthma were excluded. The initial search identified 1,409 studies and after applying the inclusion and exclusion criteria, 20 studies were finally selected for analysis (comprising data from 447,459 COPD subjects). The most frequent COPD comorbidities were: hypertension (range, 17%–64.7%), coronary artery disease (19.9%–47.8%), diabetes (10.2%–45%), osteoarthritis (18%–43.8%), psychiatric conditions (12.1%–33%), and asthma (14.7%–32.5%). Several comorbidities had an impact on the frequency and severity of COPD exacerbations, quality of life, and mortality risk, in particular malignancies, coronary artery disease, chronic heart failure, and cardiac arrhythmias. Comorbidities, especially cardiovascular diseases and diabetes, are frequent in COPD patients, and some of them are associated with higher mortality.

Characterization of Eosinophilic Bronchiectasis: A European Multicohort Study

Rationale: Bronchiectasis is classically considered a neutrophilic disorder, but eosinophilic subtypes have recently been described. Objectives: To use multiple datasets available through the European Multicentre Bronchiectasis Audit and Research Collaboration to characterize eosinophilic bronchiectasis as a clinical entity focusing on the impact of eosinophils on bronchiectasis exacerbations. Methods: Patients were included from five countries to examine the relationships between blood eosinophil counts and clinical phenotypes after excluding coexisting asthma. 16S rRNA sequencing was used to examine relationships between eosinophil counts and the sputum microbiome. A post hoc analysis of the PROMIS (Inhaled Promixin in the Treatment of Non-Cystic Fibrosis Bronchiectasis) phase 2 trial was used to examine the impact of blood eosinophil counts on exacerbations in patients with Pseudomonas aeruginosa infection. Measurements and Main Results: A relationship between sputum and blood eosinophil counts was demonstrated in two cohorts. In analysis of 1,007 patients from five countries, 22.6% of patients had blood eosinophil counts of ⩾300 cells/μl. Counts of <100 cells/μl were associated with higher bronchiectasis severity and increased mortality. There was no clear relationship with exacerbations. Blood eosinophil counts of ⩾300 cells/μl were associated with both Streptococcus- and Pseudomonas-dominated microbiome profiles. To investigate the relationship of eosinophil counts with exacerbations after controlling for the confounding effects of infection, 144 patients were studied in a clinical trial after treatment with antipseudomonal antibiotics. Compared with patients with blood eosinophil counts of <100 cells/μl (reference), elevated eosinophil counts of 100-299 cells/μl (hazard ratio, 2.38; 95% confidence interval, 1.33-4.25; P = 0.003) and ⩾300 cells/μl (hazard ratio, 3.99; 95% confidence interval, 2.20-7.85; P < 0.0001) were associated with shorter time to exacerbation. Conclusions: Eosinophilic bronchiectasis affects approximately 20% of patients. After accounting for infection status, raised blood eosinophil counts are associated with shortened time to exacerbation.

Determinants of blood eosinophil levels in the general population and patients with COPD: a population-based, epidemiological study

Background

Blood eosinophils are considered a biomarker for the treatment of chronic obstructive pulmonary disease (COPD). Population-based studies are needed to better understand the determinants of the blood eosinophil count (BEC) in individuals with and without COPD.

Methods

EPISCAN II is a multicentre, cross-sectional, population-based epidemiological study aimed at investigating the prevalence and determinants of COPD in Spain. Study subjects were randomly selected from the general population, and COPD was defined by a post-bronchodilator FEV₁/FVC < 0.7. For the pre-specified outcomes related to BEC, the first 35 COPD and 35 non-COPD subjects were consecutively recruited in 12 of the participating centres with the objective of analysing 400 individuals in each group. Baseline BEC and its association with demographic, clinical and functional variables were analysed.

Results

A total of 326 COPD and 399 non-COPD subjects were included in the analysis. The mean age (standard deviation [SD]) was 63.2 years (11.0), 46.3% were male, and 27.6% were active smokers. BEC was significantly higher in individuals with COPD [192 cells/μL (SD: 125) vs. 160 cells/μL (SD: 114); p = 0.0003]. In a stepwise multivariate model, being male, active smoker and having a previous diagnosis of asthma were independently associated with having a higher BEC.

Conclusions

This population-based study estimated the distribution of eosinophils in the healthy adult population and concluded that COPD patients have a significantly higher BEC. Male sex, active smoking and concomitant asthma were significantly associated with a higher BEC.

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.

T2 Biomarkers as Predictors of Exacerbations of Chronic Obstructive Pulmonary Disease

INTRODUCTION

Type 2 (T2) biomarkers such as blood eosinophil count (BEC) and FeNO have been related to a higher risk of exacerbations in COPD. It is unknown whether combining these biomarkers could be useful in forecasting COPD exacerbations.

METHODS

COPD patients were enrolled in this prospective, multicenter, observational study and followed up for 1 year, during which BEC were analysed at baseline (V0) while FeNO analyses were performed at baseline (V0), 6 months (V1) and 12 months (V2). The risk of moderate or severe exacerbation during follow up was assessed by Cox regression analysis, and the predictive capacity of both measurements was assessed by ROC curves and the DeLong test. Statistical significance was assumed at P<.05.

RESULTS

Of the 322 COPD patients initially recruited, 287 were followed up. At baseline, 28.0% were active smokers, and experienced moderate airflow limitation (mean FEV₁ 56.4%±17.0% predicted). Patients with at least one elevated T2 biomarker (n=125, 42.5%) were at increased risk of COPD exacerbation (HR 1.75, 95% CI 1.25-2.45, P=.001) and of shorter time to first COPD exacerbation. There was no difference between BEC and FeNO regarding the predictive capacity for moderate to severe exacerbation (AUC 0.584 vs 0.576, P=.183) but FeNO predicted severe episodes more accurately than BEC (AUC 0.607 vs 0.539, P<.05). Combining the two biomarkers enhanced the detection of moderate and severe COPD exacerbations.

CONCLUSIONS

Both eosinophil count and FeNO have limited utility for predicting COPD exacerbations. Combining these T2 biomarkers could enhance the detection of future COPD exacerbations.

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.

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.

Real-World Effectiveness of Inhalation Therapy Among Patients With Symptomatic COPD in China: A Multicenter Prospective Study

Purpose: This real-world study evaluated the effectiveness of different inhalation therapies in patients with symptomatic chronic obstructive pulmonary disease (COPD) in China and also explored the relevant factors that influence the effectiveness of inhalation therapy.

Patients and Methods: We conducted a multicenter prospective longitudinal study that was carried out in 12 hospitals in China from December 2016 to June 2021. A face-to-face interview was conducted to collect data. Baseline data were collected at the first visit. Minimum clinically important difference (MCID) was defined as attaining a COPD assessment test (CAT) decrease ≥2. We mainly assessed the MCID and the incidence of exacerbations at the 6 months follow-up.

Results: In 695 patients, the mean age was 62.5 ± 8.2 years, with a mean CAT score of 15.1 ± 6.0. Overall, 341 (49.1%) patients attained the MCID of CAT and the incidence of exacerbation during follow-up was 22.3%. Females were significantly more likely to attain MCID than male in COPD patients (adjusted odd ratio (aOR) = 1.93, adjusted 95% confidence interval (a95%CI) = 1.09–3.42, p = 0.024). Patients treated with LABA/LAMA or ICS/LABA/LAMA (ICS, inhaled corticosteroid; LABA, long-acting β2-agonist; LAMA, long-acting muscarinic antagonist) were more likely to attain MCID than patients treated with LAMA (aOR = 3.97, a95%CI = 2.48–6.35, p < 0.001; aOR = 3.17, a95%CI = 2.09–4.80, p < 0.001, respectively). Patients treated with LABA/LAMA had a higher incidence of severe exacerbation than patients treated with ICS/LABA/LAMA (aOR = 1.95, a95%CI = 1.04–3.66, p = 0.038).

Conclusion: The incidence of MCID in symptomatic COPD patients treated with inhalation therapy was nearly 50%. Patients treated with LABA/LAMA or ICS/LABA/LAMA were more likely to attain MCID than patients treated with LAMA. Patients treated with LABA/LAMA had a higher incidence of severe exacerbations than with ICS/LABA/LAMA.

Inhaled Corticosteroids and the Lung Microbiome in COPD

The Global Initiative for Chronic Obstructive Lung Disease 2021 Report recommends inhaled corticosteroid (ICS)-containing regimens as part of pharmacological treatment in patients with chronic obstructive lung disease (COPD) and frequent exacerbations, particularly with eosinophilic inflammation. However, real-world studies reveal overprescription of ICS in COPD, irrespective of disease presentation and inflammatory endotype, leading to increased risk of side effects, mainly respiratory infections. The optimal use of ICS in COPD therefore remains an area of intensive research, and additional biomarkers of benefit and risk are needed. Although the interplay between inflammation and infection in COPD is widely acknowledged, the role of the microbiome in shaping lower airway inflammation has only recently been explored. Next-generation sequencing has revealed that COPD disease progression and exacerbation frequency are associated with changes in the composition of the lung microbiome, and that the immunosuppressive effects of ICS can contribute to potentially deleterious airway microbiota changes by increasing bacterial load and the abundance of potentially pathogenic taxa such as Streptococcus and Haemophilus. Here, we explore the relationship between microbiome, inflammation, ICS use and disease phenotype. This relationship may inform the benefit:risk assessment of ICS use in patients with COPD and lead to more personalised pharmacological management.

Step-Up and Step-Down Treatment Approaches for COPD: A Holistic View of Progressive Therapies

Recent advances in inhaled drugs and a clearer definition of the disease have made the task of managing COPD more complex. Different proposals have been put forward which combine all the available treatments and the different clinical presentations in an effort to select the best therapeutic options for each clinical context. As COPD is a chronic progressive disease, the escalation of therapy has traditionally been considered the most natural way to tackle it. However, the notion of COPD as a constantly progressing disease has recently been challenged and, in specific areas, this points to the possibility of a de-escalation in treatment. In this context, the clinician requires simple, specific recommendations to guide these changes in treatment in their daily clinical practice. To accomplish this, the first step must be a correct evaluation and an accurate initial preliminary diagnosis of the patient's condition. Thereafter, the first escalation in therapy must be introduced with caution as the disease progresses, since clinical trials are not designed with clinical decision-making in mind. During this escalation, three possibilities are open to change the current treatment for a different one within the same family, to increase non-pharmacological interventions or to increase the pharmacological therapies. Beyond that point, a patient with persistent symptoms represents a complex clinical scenario which requires a specialized approach, including the evaluation of different respiratory and non-respiratory comorbidities. Unfortunately, there are few de-escalation studies available, and these are mainly observational in nature. The debate on de-escalation in pharmacological treatment, therefore, involves two main discussion points: the withdrawal of bronchodilators and the withdrawal of inhaled steroids. Altogether, the scheme for modifying treatment must be more personalized than just adding molecules, and the therapeutic response and its conditioning factors should be evaluated at each step before proceeding further.

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.

How might endotyping guide chronic obstructive pulmonary disease treatment? Current understanding, knowledge gaps and future research needs

PURPOSE OF REVIEW

This review discusses emerging therapies directed at chronic obstructive pulmonary disease (COPD) endotypes and pathobiological processes that manifest as the disease.

RECENT FINDINGS

Specific endotypes have been targeted in COPD. These include eosinophilic inflammation, overproduction of interleukin-17, chronic bronchitis and altered nature of mucous, and chronic infection. Therapies exactly directed at the cause of these endotypes or their resultant clinical findings have been assessed. Although some intermediate outcomes have seemed promising, there have been no findings that shift the paradigm of COPD therapy.

SUMMARY

Basic and clinical scientists continue to define endotypes that may be directly addressed with therapeutics. As of the time of this up-to-date review, there is yet to be an endotype-directed therapy to demonstrate great clinical effect.