Blood eosinophil count thresholds and exacerbations in patients with chronic obstructive pulmonary disease

Clinical Characteristics and 2-Year Outcomes of Chronic Obstructive Pulmonary Disease Patients With High Blood Eosinophil Counts: A Population-based Prospective Cohort Study in China

BACKGROUND

High blood eosinophil count (BEC) is a useful biomarker for guiding inhaled corticosteroid therapy in patients with chronic obstructive pulmonary disease (COPD), yet its implications in a community setting remain underexplored. This study aimed to elucidate the clinical characteristics and outcomes of COPD patients with high BEC within the Chinese community.

METHODS

We obtained baseline and 2-year follow-up data from COPD patients (post-bronchodilator forced expiratory volume in 1 second/forced vital capacity <0.70) in the early COPD study. Patients with a BEC ≥300cells/μL were classified as the high BEC group. We assessed differences in the clinical characteristics and outcomes between high and low BEC patients. Subgroup analyses were conducted on COPD patients without a history of corticosteroid use or asthma.

RESULTS

Of the 897 COPD patients, 205 (22.9%) had high BEC. At baseline, high BEC patients exhibited a higher proportion of chronic respiratory symptoms, lower lung function, and more severe small airway dysfunction than low BEC patients. Over the 2-year period, high BEC patients experienced a significantly higher risk of acute exacerbations (relative risk: 1.28, 95% confidence interval: 1.09-1.49; P=0.002), even after adjusting for confounders. No significant difference was observed in lung function decline rates. The subgroup analysis yielded consistent results.

CONCLUSIONS

COPD patients with high BEC in a Chinese community exhibited poorer health status, more severe small airway dysfunction, and a higher risk of exacerbations. Future research should explore the pathological mechanisms underlying the poorer prognosis in patients with high BEC.

Dupilumab for COPD with Blood Eosinophil Evidence of Type 2 Inflammation

BACKGROUND

Dupilumab, a fully human monoclonal antibody that blocks the shared receptor component for interleukin-4 and interleukin-13, key and central drivers of type 2 inflammation, has shown efficacy and safety in a phase 3 trial involving patients with chronic obstructive pulmonary disease (COPD) and type 2 inflammation and an elevated risk of exacerbation. Whether the findings would be confirmed in a second phase 3 trial was unclear.

METHODS

In a phase 3, double-blind, randomized trial, we assigned patients with COPD who had a blood eosinophil count of 300 cells per microliter or higher to receive subcutaneous dupilumab (300 mg) or placebo every 2 weeks. The primary end point was the annualized rate of moderate or severe exacerbations. Key secondary end points, analyzed in a hierarchical manner to adjust for multiplicity, included the changes from baseline in the prebronchodilator forced expiratory volume in 1 second (FEV1) at weeks 12 and 52 and in the St. George's Respiratory Questionnaire (SGRQ; scores range from 0 to 100, with lower scores indicating better quality of life) total score at week 52.

RESULTS

A total of 935 patients underwent randomization: 470 were assigned to the dupilumab group and 465 to the placebo group. As prespecified, the primary analysis was performed after a positive interim analysis and included all available data for the 935 participants, 721 of whom were included in the analysis at week 52. The annualized rate of moderate or severe exacerbations was 0.86 (95% confidence interval [CI], 0.70 to 1.06) with dupilumab and 1.30 (95% CI, 1.05 to 1.60) with placebo; the rate ratio as compared with placebo was 0.66 (95% CI, 0.54 to 0.82; P<0.001). The prebronchodilator FEV1 increased from baseline to week 12 with dupilumab (least-squares mean change, 139 ml [95% CI, 105 to 173]) as compared with placebo (least-squares mean change, 57 ml [95% CI, 23 to 91]), with a significant least-squares mean difference at week 12 of 82 ml (P<0.001) and at week 52 of 62 ml (P = 0.02). No significant between-group difference was observed in the change in SGRQ scores from baseline to 52 weeks. The incidence of adverse events was similar in the two groups and consistent with the established profile of dupilumab.

CONCLUSIONS

In patients with COPD and type 2 inflammation as indicated by elevated blood eosinophil counts, dupilumab was associated with fewer exacerbations and better lung function than placebo. (Funded by Sanofi and Regeneron Pharmaceuticals; NOTUS ClinicalTrials.gov number, NCT04456673.).

Type 2 Biomarkers and Their Clinical Implications in Bronchiectasis: A Prospective Cohort Study

PURPOSE

Bronchiectasis is predominantly marked by neutrophilic inflammation. The relevance of type 2 biomarkers in disease severity and exacerbation risk is poorly understood. This study explores the clinical significance of these biomarkers in bronchiectasis patients.

METHODS

In a cross-sectional cohort study, bronchiectasis patients, excluding those with asthma or allergic bronchopulmonary aspergillosis, underwent clinical and radiological evaluations. Bronchoalveolar lavage samples were analyzed for cytokines and microbiology. Blood eosinophil count (BEC), serum total immunoglobulin E (IgE), and fractional exhaled nitric oxide (FeNO) were measured during stable disease states. Positive type 2 biomarkers were defined by established thresholds for BEC, total IgE, and FeNO.

RESULTS

Among 130 patients, 15.3% demonstrated BEC ≥ 300 cells/μL, 26.1% showed elevated FeNO ≥ 25 ppb, and 36.9% had high serum total IgE ≥ 75 kU/L. Approximately 60% had at least one positive type 2 biomarker. The impact on clinical characteristics and disease severity was variable, highlighting BEC and FeNO as reflective of different facets of disease severity and exacerbation risk. The combination of low BEC with high FeNO appeared to indicate a lower risk of exacerbation. However, Pseudomonas aeruginosa colonization and a high neutrophil-to-lymphocyte ratio (NLR ≥ 3.0) were identified as more significant predictors of exacerbation frequency, independent of type 2 biomarker presence.

CONCLUSIONS

Our study underscores the distinct roles of type 2 biomarkers, highlighting BEC and FeNO, in bronchiectasis for assessing disease severity and predicting exacerbation risk. It advocates for a multi-biomarker strategy, incorporating these with microbiological and clinical assessments, for comprehensive patient management.

Correlation of fractional exhaled nitric oxide (FeNO) and clinical outcomes in patients with chronic obstructive pulmonary disease: A prospective cohort study

BACKGROUND

Fractional exhaled nitric oxide (FeNO) is an acceptable and noninvasive marker for defining eosinophilic airway inflammation. Further study is necessary to clarify the role of FeNO in patients with chronic obstructive pulmonary disease (COPD). This study aimed to determine the association between FeNO levels and clinical outcomes.

METHODS

A prospective observational study was conducted at Songklanagarind Hospital from October 2020 to November 2022. FeNO testing and spirometry were performed at the initial visit and 12-month follow-up. Exacerbation, hospitalization, lung function decline, and all-cause mortality were analyzed to determine the association between FeNO levels and clinical outcomes.

RESULTS

A total of 60 patients with COPD were enrolled, 88.3 % of whom were male, with a mean age of 71.3 ± 9.5 years. There were 18 patients (30 %) in the high FeNO group (≥25 ppb) and 42 patients (70 %) in the low (<25 ppb) FeNO group. The mean blood eosinophil count (BEC) was significantly higher in the high FeNO group (p < 0.001). After a 12-month follow-up period, high FeNO group had higher exacerbation events (HR of 1.26, 95 % confidence interval (CI), 1.10-1.97, p= 0.025). Hospitalization and mortality rates were significantly higher in the high FeNO group. Regardless of the inhaled corticosteroids used, patients with high BEC and FeNO levels tended to have a greater risk of exacerbation.

CONCLUSION

In patients with COPD, FeNO levels are strongly correlated with BEC. Poor clinical outcomes were reported in patients with high FeNO levels. FeNO may be a useful biomarker for predicting clinical outcomes in patients with COPD.

Clinical Characteristics and Frequency of Chronic Obstructive Pulmonary Disease Exacerbations in Korean Patients: Findings From the KOCOSS Cohort 2012-2021

BACKGROUND

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) exert a substantial burden on patients and healthcare systems; however, data related to the frequency of AECOPD in the Korean population are limited. Therefore, this study aimed to describe the frequency of severe, and moderate or severe AECOPD, as well as clinical and demographic characteristics of patients with chronic obstructive pulmonary disease (COPD) in South Korea.

METHODS

Data from patients aged > 40 years with post-bronchodilator forced expiratory volume in 1 second (FEV1)/forced vital capacity ≤ 70% of the normal predicted value from the Korea COPD Subgroup Study database were analyzed (April 2012 to 2021). The protocol was based on the EXAcerbations of COPD and their OutcomeS International study. Data were collected retrospectively for year 0 (0-12 months before study enrollment) based on patient recall, and prospectively during years 1, 2, and 3 (0-12, 13-24, and 25-36 months after study enrollment, respectively). The data were summarized using descriptive statistics.

RESULTS

Data from 3,477 Korean patients (mean age, 68.5 years) with COPD were analyzed. Overall, most patients were male (92.3%), former or current smokers (90.8%), had a modified Medical Research Council dyspnea scale score ≥ 1 (83.3%), and had moderate airflow limitation (54.4%). The mean body mass index (BMI) of the study population was 23.1 kg/m², and 27.6% were obese or overweight. Hypertension was the most common comorbidity (37.6%). The mean blood eosinophil count was 226.8 cells/μL, with 21.9% of patients having ≥ 300 cells/μL. A clinically insignificant change in FEV1 (+1.4%) was observed a year after enrollment. Overall, patients experienced a mean of 0.2 severe annual AECOPD and approximately 1.1 mean moderate or severe AECOPD. Notably, the rates of severe AECOPD remained generally consistent over time. Compared with patients with no exacerbations, patients who experienced severe exacerbations had a lower mean BMI (21.7 vs. 23.1 kg/m²; P < 0.001) and lower lung function parameters (all P values < 0.001), but reported high rates of depression (25.5% vs. 15.1%; P = 0.044) and anxiety (37.3% vs. 16.7%; P < 0.001) as a comorbidity.

CONCLUSION

Findings from this Korean cohort of patients with COPD indicated a high exacerbation burden, which may be attributable to the unique characteristics of the study population and suboptimal disease management. This highlights the need to align clinical practices with the latest treatment recommendations to alleviate AECOPD burden in Korea.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05750810.

Monitoring COPD patients: systemic and bronchial eosinophilic inflammation in a 2-year follow-up

BACKGROUND

High blood eosinophils seem to predict exacerbations and response to inhaled corticosteroids (ICS) treatment in patients with chronic obstructive pulmonary disease (COPD). The aim of our study was to prospectively evaluate for 2 years, blood and sputum eosinophils in COPD patients treated with bronchodilators only at recruitment.

METHODS

COPD patients in stable condition treated with bronchodilators only underwent monitoring of lung function, blood and sputum eosinophils, exacerbations and comorbidities every 6 months for 2 years. ICS was added during follow-up when symptoms worsened.

RESULTS

63 COPD patients were enrolled: 53 were followed for 1 year, 41 for 2 years, 10 dropped-out. After 2 years, ICS was added in 12/41 patients (29%) without any statistically significant difference at time points considered. Blood and sputum eosinophils did not change during follow-up. Only FEV1/FVC at T0 was predictive of ICS addition during the 2 year-follow-up (OR:0.91; 95% CI: 0.83-0.99, p = 0.03). ICS addition did not impact on delta (T24-T0) FEV1, blood and sputum eosinophils and exacerbations. After 2 years, patients who received ICS had higher blood eosinophils than those in bronchodilator therapy (p = 0.042). Patients with history of ischemic heart disease increased blood eosinophils after 2 years [p = 0.03 for both percentage and counts].

CONCLUSIONS

Blood and sputum eosinophils remained stable during the 2 year follow-up and were not associated with worsened symptoms or exacerbations. Almost 30% of mild/moderate COPD patients in bronchodilator therapy at enrollment, received ICS for worsened symptoms in a 2 year-follow-up and only FEV1/FVC at T0 seems to predict this addition. History of ischemic heart disease seems to be associated with a progressive increase of blood eosinophils.

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.

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.

Immune Dysregulation in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a disease whose incidence increase with age and is characterised by chronic inflammation and significant immune dysregulation. Inhalation of toxic substances cause oxidative stress in the lung tissue as well as airway inflammation, under the recruitment of chemokines, immune cells gathered and are activated to play a defensive role. However, persistent inflammation damages the immune system and leads to immune dysregulation, which is mainly manifested in the reduction of the body's immune response to antigens, and immune cells function are impaired, further destroy the respiratory defensive system, leading to recurrent lower respiratory infections and progressive exacerbation of the disease, thus immune dysregulation play an important role in the pathogenesis of COPD. This review summarizes the changes of innate and adaptive immune-related cells during the pathogenesis of COPD, aiming to control COPD airway inflammation and improve lung tissue remodelling by regulating immune dysregulation, for further reducing the risk of COPD progression and opening new avenues of therapeutic intervention in COPD.

High Blood Eosinophil Count at Stable State is Not Associated with Airway Microbiota Distinct Profile in COPD

Purpose

The heterogeneity of clinical features in COPD at stable state has been associated with airway microbiota. Blood eosinophil count (BEC) represents a biomarker for a pejorative evolution of COPD, including exacerbations and accelerated FEV1 decline. We aimed to analyse the associations between BEC and airway microbiota in COPD at stable state.

Patients and Methods

Adult COPD patients at stable state (RINNOPARI cohort) were included and characterised for clinical, functional, biological and morphological features. BEC at inclusion defined 2 groups of patients with low BEC <300/mm3 and high BEC ≥300/mm3. Sputa were collected and an extended microbiological culture was performed for the identification of viable airway microbiota.

Results

Fifty-nine subjects were included. When compared with the low BEC (n=40, 67.8%), the high BEC group (n=19, 32.2%) had more frequent exacerbations (p<0.001) and more pronounced cough and sputum (p<0.05). The global composition, the number of bacteria per sample and the α-diversity of the microbiota did not differ between groups, as well as the predominant phyla (Firmicutes), or the gender repartition.

Conclusion

In our study, high BEC in COPD at stable state was associated with a clinical phenotype including frequent exacerbation, but no distinct profile of viable airway microbiota compared with low BEC.

Inhaled Corticosteroids in Subjects with Chronic Obstructive Pulmonary Disease: An Old, Unfinished History

Chronic obstructive pulmonary disease (COPD) is one of the major causes of disability and death. Maintenance use of inhaled bronchodilator(s) is the cornerstone of COPD pharmacological therapy, but inhaled corticosteroids (ICSs) are also commonly used. This narrative paper reviews the role of ICSs as maintenance treatment in combination with bronchodilators, usually in a single inhaler, in stable COPD subjects. The guidelines strongly recommend the addition of an ICS in COPD subjects with a history of concomitant asthma or as a step-up on the top of dual bronchodilators in the presence of hospitalization for exacerbation or at least two moderate exacerbations per year plus high blood eosinophil counts (≥300/mcl). This indication would only involve some COPD subjects. In contrast, in real life, triple inhaled therapy is largely used in COPD, independently of symptoms and in the presence of exacerbations. We will discuss the results of recent randomized controlled trials that found reduced all-cause mortality with triple inhaled therapy compared with dual inhaled long-acting bronchodilator therapy. ICS use is frequently associated with common local adverse events, such as dysphonia, oral candidiasis, and increased risk of pneumonia. Other side effects, such as systemic toxicity and unfavorable changes in the lung microbiome, are suspected mainly at higher doses of ICS in elderly COPD subjects with comorbidities, even if not fully demonstrated. We conclude that, contrary to real life, the use of ICS should be carefully evaluated in stable COPD patients.

National Development in the Use of Inhaled Corticosteroid Treatment in Chronic Obstructive Pulmonary Disease: Repeated Cross-Sectional Studies from 1998 to 2018

Recommendations for the treatment of chronic obstructive pulmonary disease (COPD) have shifted towards a more restrictive use of inhaled corticosteroids (ICS). We aimed to identify the nationwide development over time in the use of ICS treatment in COPD. We conducted a register-based repeated cross-sectional study using Danish nationwide registers. On a yearly basis from 1998 to 2018, we included all patients in Denmark ≥ 40 years of age with an ICD-10 diagnosis of COPD (J44). Accumulated ICS use was calculated for each year based on redeemed prescriptions. Patients were divided into the following groups: No ICS, low-dose ICS, medium-dose ICS, or high-dose ICS. From 1998 to 2018, the yearly proportion of patients without ICS treatment increased (from 50.6% to 57.6%), the proportion of patients on low-dose ICS treatment increased (from 11.3% to 14.9%), and the proportion of patients on high-dose ICS treatment decreased (from 17.0% to 9.4%). We demonstrated a national reduction in the use of ICS treatment in COPD from 1998 to 2018, with an increase in the proportion of patients without ICS and on low-dose ICS treatment and a decrease in the proportion of patients on high-dose ICS treatment.

Blood Eosinophil Count and Its Determinants in a Chinese Population-Based Cohort

INTRODUCTION

Blood eosinophil count has been shown markedly variable across different populations. However, its distribution in Chinese general population remains unclear. We aimed to investigate blood eosinophil count and its determinants in a Chinese general population.

METHODS

In this population-based study, general citizens of Sichuan province in China were extracted from the China Pulmonary Health study. Data on demographics, personal and family history, living condition, lifestyle, spirometry, and complete blood count test were obtained and analyzed. A stepwise multivariate binary logistic regression analysis was performed to identify determinants of high blood eosinophils (>75th percentile).

RESULTS

A total of 3,310 participants were included, with a mean age (standard deviation) of 47.0 (15.6) years. In total population, the median blood eosinophil count was 110.0 (interquartile range [IQR]: 67.2-192.9) cells/μL, lower than that in smokers (133.4 cells/μL, IQR: 79.3-228.4) and patients with asthma (140.7 cells/μL, IQR: 79.6-218.2) or post-bronchodilator airflow limitation (141.5 cells/μL, IQR: 82.6-230.1), with a right-skewed distribution. Multivariate analyses revealed that oldness (aged ≥60 years) (odds ratio [OR]: 1.66, 95% confidence interval [CI]: 1.11-2.48), smoking ≥20 pack-years (OR: 1.90, 95% CI: 1.20-3.00), raising a dog/cat (OR: 1.72, 95% CI: 1.17-2.52), and occupational exposure to dust, allergen, and harmful gas (OR: 1.58, 95% CI: 1.15-2.15) were significantly associated with high blood eosinophils.

CONCLUSION

This study identifies a median blood eosinophil count of 110.0 cells/μL and determinants of high blood eosinophils in a Chinese general population, including oldness (aged ≥60 years), smoking ≥20 pack-years, raising a dog/cat, and occupational exposure to dust, allergen, and harmful gas.

Eosinophils promote pulmonary matrix destruction and emphysema via Cathepsin L

Patients with chronic obstructive pulmonary disease (COPD) who exhibit elevated blood eosinophil levels often experience worsened lung function and more severe emphysema. This implies the potential involvement of eosinophils in the development of emphysema. However, the precise mechanisms underlying the development of eosinophil-mediated emphysema remain unclear. In this study, we employed single-cell RNA sequencing to identify eosinophil subgroups in mouse models of asthma and emphysema, followed by functional analyses of these subgroups. Assessment of accumulated eosinophils unveiled distinct transcriptomes in the lungs of mice with elastase-induced emphysema and ovalbumin-induced asthma. Depletion of eosinophils through the use of anti-interleukin-5 antibodies ameliorated elastase-induced emphysema. A particularly noteworthy discovery is that eosinophil-derived cathepsin L contributed to the degradation of the extracellular matrix, thereby leading to emphysema in pulmonary tissue. Inhibition of cathepsin L resulted in a reduction of elastase-induced emphysema in a mouse model. Importantly, eosinophil levels correlated positively with serum cathepsin L levels, which were higher in emphysema patients than those without emphysema. Expression of cathepsin L in eosinophils demonstrated a direct association with lung emphysema in COPD patients. Collectively, these findings underscore the significant role of eosinophil-derived cathepsin L in extracellular matrix degradation and remodeling, and its relevance to emphysema in COPD patients. Consequently, targeting eosinophil-derived cathepsin L could potentially offer a therapeutic avenue for emphysema patients. Further investigations are warranted to explore therapeutic strategies targeting cathepsin L in emphysema patients.

Differences in hospital admissions for acute exacerbations of COPD during the COVID-19 pandemic stratified by stable-state blood eosinophil count

Acute exacerbations of COPD (AECOPD) are driven through different triggers, including infection such as viruses and bacteria. However, nearly 40% of exacerbations are associated with a blood eosinophilia and related to type 2 inflammation (T2-high) [1].

Hospital admission for exacerbations of COPD fell only in non-T2-high patients during the COVID-19 pandemic and only in non-eosinophilic admissions. Phenotyping of AECOPD, including at time of exacerbation, is needed for personalised management. https://bit.ly/3ZiUtYx

Effects of doxofylline as an adjuvant on severe exacerbation and long-term prognosis for COPD with different clinical subtypes

OBJECTIVE

This study aimed to investigate the effectiveness of doxofylline as an adjuvant in reducing severe exacerbation for different clinical subtypes of chronic obstructive pulmonary disease (COPD).

METHODS

The clinical trial was an open-label non-randomized clinical trial that enrolled patients with COPD. The patients were divided into two groups (doxofylline group[DG] and non-doxofylline group[NDG]) according to whether the adjuvant was used. Based on the proportion of inflammatory cells present, the patients were divided into neutrophilic, eosinophilic, and mixed granulocytic subtypes. The rates of severe acute exacerbation, use of glucocorticoids, and clinical symptoms were followed up in the first month, the third month, and the sixth month after discharge.

RESULTS

A total of 155 participants were included in the study. The average age of the participants was 71.2  ±  10.1 years, 52.3% of the patients were male, and 29.7% of the participants had extremely severe cases of COPD. In the third month after discharge the numbers of patients exhibiting severe exacerbation among the neutrophilic subtype were 5 (6.6%) in the DG versus 17 (22.4%) in the NDG (incidence rate ratio[IRR] = 0.4 [95% CI: 0.2-0.9] P = 0.024). In the sixth month after discharge, the numbers were 3 (3.9%) versus 13 (17.1%; IRR = 0.3 [95%; CI: 0.1-0.9], P = 0.045), and those for the eosinophilic subtype were 0 (0.0%) versus 4 (14.8%), P = 0.02. In the eosinophilic subtype, the results for forced expiratory volume in the first second and maximal mid-expiratory flow were significantly higher in the DG. The mean neutrophil and eosinophil levels were significantly lower than in the NDG among the neutrophilic subtype, and the neutrophil percentage was lower than in the NDG among the eosinophilic subtype. At the six-month follow-up, the dose adjustment rates of the neutrophilic and eosinophilic subtypes showed a significant difference (P< 0.05).

CONCLUSIONS

As an adjuvant drug, doxofylline has a good therapeutic effect on patients with the neutrophilic and eosinophilic clinical subtypes of COPD. It can reduce the incidence of severe exacerbation, the use of glucocorticoids, and inflammatory reactions in the long term (when used for a minimum of 3 months).

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.

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.

Exacerbations of COPD

COPD exacerbations are associated with significant morbidity, mortality, and increased health care expenditures. The recently published Global Initiative for Chronic Obstructive Lung Disease (GOLD) recommendations have further refined the definition of an exacerbation. A better understanding of the risk factors associated with the development of an exacerbation exists, and improvements are being made in earlier detection approaches. Pharmacologic treatment strategies have been the cornerstone of effective therapy. In addition, both pharmacologic and non-pharmacologic strategies have been proven successful in the prevention of future exacerbations. Newer technologies, including the use of artificial intelligence and wearable monitoring devices, are now being used to help in the earlier detection of exacerbations. Such preventive and earlier detection strategies can help to develop a more personalized care model and improve outcomes for patients with COPD.

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.

Anti-IL5/IL5R Treatment in COPD: Should We Target Oral Corticosteroid-Dependent Patients?

Introduction

Monoclonal antibodies targeting interleukin 5 (IL5) or its receptor (IL5R) are frequently used in severe asthma, in which they reduce exacerbations rate and oral corticosteroids (OCS) exposure. Anti-IL5/IL5Rs have been studied in patients with chronic obstructive pulmonary disease (COPD) without convincing benefits. However, these therapies have been used in clinical practice in COPD with apparently good results.

Purpose

To describe the clinical characteristics and therapeutic response of COPD patients treated with anti-IL5/IL5R in a real-world setting.

Patients and Methods

This is a retrospective case series of patients followed at the Quebec Heart and Lung Institute COPD clinic. Men or women, with an established diagnosis of COPD, and treated either with Mepolizumab or Benralizumab were included. Demographics, disease and exacerbation-related data, airway comorbidities, lung function, and inflammatory profile were extracted from patients' hospital files at baseline visit and 12 months post-treatment. Therapeutic response to biologics was assessed by measuring change in annual exacerbation rate and/or OCS daily dose.

Results

Seven COPD patients treated with biologics were identified (5M:2F). All were found to be OCSdependent at baseline. Radiological evidence of emphysema was found in all patients. One case was diagnosed with asthma before age 40. Residual eosinophilic inflammation was found in 5/6 patients (blood eosinophils count 237 ± 225×106 cells/L) despite chronic OCS use. After 12 months of anti-IL5 treatment, mean OCS dose dropped from 12.0 ± 7.6 to 2.6 ± 4.3 mg/day, representing a 78% decrease. Annual exacerbations rate was reduced by 88%, from 8.2 ± 3.3 to 1.0 ± 1.2 per year.

Conclusion

Chronic OCS use is a common characteristic of patients treated with anti-IL5/IL5R biological therapies in this real-world setting. In this population, it may be effective in decreasing OCS exposure and exacerbation.

The clinical efficacy of type 2 monoclonal antibodies in eosinophil-associated chronic airway diseases: a meta-analysis

Background

Anti-type 2 inflammation therapy has been proposed as a treatment strategy for eosinophil-associated chronic airway disorders that could reduce exacerbations and improve lung function. We performed a meta-analysis of randomized controlled trials to assess the effectiveness of type 2 monoclonal antibodies (anti-T2s) for eosinophil-associated chronic airway disorders.

Methods

PubMed, Embase, Web of Science, and Cochrane Library were searched from their inception to 21 August 2022. Randomized clinical trials evaluating the effectiveness of anti-T2s versus placebo in the treatment of chronic airway diseases were selected. The outcomes were exacerbation rate and change in pre-bronchodilator forced expiratory volume in 1 s (FEV1) from baseline. The Cochrane Risk of Bias Assessment Tool 1.0 was used to evaluate the risk of bias, and the random-effects or fixed-effect model were used to pool the data.

Results

Thirty-eight articles concerning forty-one randomized clinical trials with 17,115 patients were included. Compared with placebo, anti-T2s therapy yielded a significant reduction in exacerbation rate in COPD and asthma (Rate Ratio (RR)=0.89, 95%CI, 0.83-0.95, I2 = 29.4%; RR= 0.59, 95%CI, 0.52-0.68, I2 = 83.9%, respectively) and improvement in FEV1 in asthma (Standard Mean Difference (SMD)=0.09, 95%CI, 0.08-0.11, I2 = 42.6%). Anti-T2s therapy had no effect on FEV1 improvement in COPD (SMD=0.05, 95%CI, -0.01-0.10, I2 = 69.8%).

Conclusion

Despite inconsistent findings across trials, anti-T2s had a positive overall impact on patients' exacerbation rate in asthma and COPD and FEV1 in asthma. Anti-T2s may be effective in treating chronic airway illnesses related to eosinophils.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022362280.

Revealing EXPH5 as a potential diagnostic gene biomarker of the late stage of COPD based on machine learning analysis

Chronic obstructive pulmonary disease is a kind of chronic lung disease characterized by persistent air flow obstruction, which was the third leading cause of death in China. The incidence of COPD is steadily and increasing and has been a globally sever disease. Accordingly, it is urgently needed to explore how to diagnose and treat COPD timely. This study aims to find key genes to diagnose COPD as soon as possible to avoid COPD processing and analyze immune cell infiltration between COPD early stage and late stage. Two GEO datasets were merged as the merge data for analyses. 157 DEGs were used for GSEA analysis to find the pathway between COPD early stage and late stage. Above all, gene EXPH5 stood out from the screen as the most likely candidate diagnosis biomarker of COPD indicating the late-stage by least LASSO and SVM-RFE. ROC curves of EXPH5 were applied to represent the discriminatory ability through the area under the curve which is the gold standard to evaluate the accuracy of diagnosis and survival rate. The CIBERSORT algorithm was used to assess the distribution of tissue-infiltrating immune cells between two COPD stages. The diagnosis biomarker, gene EXPH5 had a positive correlation with NK cells resting; mast cell resting, eosinophils, and negative correlation with T cell gamma delta, macrophages M1, which underscore the role of gene and immune cell infiltration. To make results more reliable, we further analyzed the gene EXPH5 expression in single-cell transcriptome data and showed again that EXPH5 genes significantly downregulated in the late stage of COPD especially in the main lung cell types AT1 and AT2. In a word, our study identified genes EXPH5 as a marker gene, which adds to the knowledge for clinical diagnosis and pharmaceutical design of COPD.

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.

Stability of Blood Eosinophils in COPD with Multiple Acute Exacerbations Within 1 Year and Its Relationship with Prognosis

Background

The relationship between increased blood eosinophils (EOS) and the prognosis of patients with chronic obstructive pulmonary disease (COPD) remains controversial. We aimed to explore the stability of blood eosinophils in patients with multiple hospitalizations for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) over a 1-year period and its relationship with readmission rates and mortality.

Methods

Prospectively include patients with at least 2 hospitalizations for AECOPD in 1 year between June 2019 and December 2021. Using 150 cells/ul as the cut-off value, the study population was divided into EOS, non-EOS, and fluctuating groups based on the longitudinal stability of blood EOS. The relationship between blood EOS and readmission rate and mortality was analyzed according to the 6-month follow-up after hospital discharge.

Results

A total of 202 patients were included. 48, 108, and 46 patients were in the EOS, non-EOS, and fluctuating groups, respectively. The stability of blood EOS at 1 year was 77.2%. The risk of death was lower in the EOS group compared to the non-EOS group (HR=0.323, 95% CI 0.113-0.930, P =0.036). The risk of readmission was lower in both the EOS group (HR=0.486, 95% CI 0.256-0.923, P =0.027) and the non-EOS group (HR=0.575, 95% CI 0.347-0.954, P = 0.032) than in the fluctuating group.

Conclusion

The blood EOS of COPD patients is relatively stable over 1 year. Patients with consistently high blood EOS had a lower risk of all-cause mortality after discharge; patients with fluctuating blood EOS had a higher risk of readmission.

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.

Fractional Exhaled Nitric Oxide (FeNO) in Patients with Stable Chronic Obstructive Pulmonary Disease: Short-Term Variability and Potential Clinical Implications

BACKGROUND

The use of fractional exhaled nitric oxide (FeNO) has been proposed for identifying and monitoring eosinophilic airway inflammation in chronic obstructive pulmonary disease (COPD). To explore the clinical utility of FeNO in COPD, we aimed to assess its short-term variability in a clinically stable COPD cohort.

METHODS

Consecutive COPD patients, formerly smokers, underwent FeNO assessment at the baseline and six time-points through serial sampling spaced 3 days apart.

RESULTS

A total of 41 patients (mean age 72.9, 87.8% males) showed a median baseline value of FeNO of 11.7 (8.0-16.8) ppb. A weak linear relationship was documented between baseline FeNO values and both eosinophil counts (r = 0.341, p = 0.029) and the percentage of eosinophils (r = 0.331, p = 0.034), confirmed in multiple linear regressions after adjusting for steroid use. The overall individual variability of FeNO between time-points was 3.90 (2.53-7.29) ppb, with no significant difference in the distribution of FeNO values measured at different time-points (p = 0.204). A total of 28 (68.3%) patients exhibited FeNO always below the 25 ppb cut-off at all determinations, while the remining 13 (31.7%) had at least one value above the established limit. Interestingly, none of these 13 participants had FeNO stably above 25 ppb, all showing at least one normal value during serial sampling. Compared to these patients with more fluctuating values, the 28 with stably normal FeNO only exhibited a significantly higher body weight (80.0 ± 18.2 kg vs. 69.0 ± 8.8 kg, p = 0.013) and body mass index (29.7 ± 6.5 kg/m2 vs. 25.9 ± 3.7 kg/m2, p = 0.026), confirmed in multiple logistic regressions after adjusting for major potential confounders.

CONCLUSIONS

A certain degree of FeNO variability, apparently unrelated to eosinophil counts but somehow influenced by body weight, must be considered in COPD patients. Further studies are needed to clarify whether this biomarker may be effectively used to plan more personalized pharmacological and rehabilitation strategies in this clinical setting.

Patients with Chronic Obstructive Pulmonary Disease and Evidence of Eosinophilic Inflammation Experience Exacerbations Despite Receiving Maximal Inhaled Maintenance Therapy

Background

Some patients with chronic obstructive pulmonary disease (COPD) experience frequent exacerbations despite maximal inhaled therapy (“triple therapy”), possibly leading to high health care resource utilization (HCRU).

Aim

Describe characteristics, future HCRU, and mortality of patients with COPD who experience frequent exacerbations despite triple therapy; characterize individuals who may be candidates for biologic therapies.

Methods

This descriptive observational study used primary care data of patients aged ≥40 years in the United Kingdom receiving maintenance therapy for COPD who had ≥1 year of data prior to index date and ≥1 year of follow-up data. We described these patients’ clinical and demographic characteristics, including blood eosinophil counts (BEC), pattern of exacerbations, hospitalizations, and corticosteroid exposure, as well as future exacerbations, hospitalizations, and death.

Results

Of 43,753 patients with maintenance-treated COPD, 6480 experienced exacerbations despite ≥3 months of triple therapy. Of these, 5669 had available BEC: 1287 (22.7%) had BEC ≥250 cells/µL and ≥3 exacerbations in the year prior to the index date; 471 (36.6%) received ≥4 acute courses of oral corticosteroids. Patients with a pattern of high disease burden continued to have high disease burden: 51.1% experienced ≥3 exacerbations and 2.6% experienced ≥3 hospitalizations. Patients who experienced exacerbations despite triple therapy had a significantly higher risk of COPD-related death than other maintenance-treated patients (5.8% vs 2.1%).

Conclusion

Nearly one-quarter of patients receiving triple therapy for COPD who experienced frequent exacerbations had elevated BEC and ≥3 exacerbations, suggesting a potential mechanism of persistent eosinophilic inflammation that could be a target for eosinophil-depleting biologic therapy.

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.

Clinical Characteristics and Outcome Related to Blood Eosinophilic Chronic Obstructive Pulmonary Disease (COPD) Patients

Introduction

The term chronic obstructive pulmonary disease (COPD) refers to a range of illnesses that impair breathing and airflow. Clinical history of COPD is further impacted by frequent exacerbations known as acute exacerbation COPD in which these specific symptoms worsen contributing to emergency room (ER) visits and hospitalization. Blood eosinophils are a crucial indicator of therapy effectiveness and exacerbation rate. The role of blood eosinophils as a biomarker for treatment, response, exacerbation risk, inflammation, and other symptoms in COPD patients is implemented by the Global Initiative Obstructive Lung Disease (GOLD) as guidelines.

Objective

To determine the clinical characteristics and outcomes related specifically to eosinophilic COPD Patients.

Methodology

This is a retrospective single-center study of all AECOPD presented at ET between 2018 to 2019. A total of 120 patients were included. Patients were divided into two groups depending on blood eosinophil count: high (>300cells/µL) and low (<300cell/µL). Finally, Binary logistics regression was performed to determine correlations between clinical characteristics and eosinophil count levels.

Results

In the high eosinophil patients’ group: none of the independent variables were statistically significant. However, in the low eosinophil patients’ group: ER visits, lung disease, and symptomatic exacerbation made a statically significant contribution to the model (p-value of .008, .01, .001) respectively.

Conclusion and recommendation

The higher eosinophil levels showed better clinical outcomes compared to lower eosinophil levels. Increasing the level of symptomatic AECOPD episodes in low eosinophil levels may be linked to the onset of bacterial infection and airway inflammation. The study further recommends a prospective cross-sectional multi-center study which includes a follow-up of the patients to assess the number of exacerbations after initial treatment

Phenotype of Asthma-COPD Overlap in COPD and Severe Asthma Cohorts

BACKGROUND

Asthma and chronic obstructive pulmonary disease (COPD) are airway diseases with similar clinical manifestations, despite differences in pathophysiology. Asthma-COPD overlap (ACO) is a condition characterized by overlapping clinical features of both diseases. There have been few reports regarding the prevalence of ACO in COPD and severe asthma cohorts. ACO is heterogeneous; patients can be classified on the basis of phenotype differences. This study was performed to analyze the prevalence of ACO in COPD and severe asthma cohorts. In addition, this study compared baseline characteristics among ACO patients according to phenotype.

METHODS

Patients with COPD were prospectively enrolled into the Korean COPD subgroup study (KOCOSS) cohort. Patients with severe asthma were prospectively enrolled into the Korean Severe Asthma Registry (KoSAR). ACO was defined in accordance with the updated Spanish criteria. In the COPD cohort, ACO was defined as bronchodilator response (BDR) ≥ 15% and ≥ 400 mL from baseline or blood eosinophil count (BEC) ≥ 300 cells/μL. In the severe asthma cohort, ACO was defined as age ≥ 35 years, smoking ≥ 10 pack-years, and post-bronchodilator forced expiratory volume in 1 s/forced vital capacity < 0.7. Patients with ACO were divided into four groups according to smoking history (threshold: 20 pack-years) and BEC (threshold: 300 cells/μL).

RESULTS

The prevalence of ACO significantly differed between the COPD and severe asthma cohorts (19.8% [365/1,839] vs. 12.5% [104/832], respectively; P < 0.001). The percentage of patients in each group was as follows: group A (light smoker with high BEC) - 9.1%; group B (light smoker with low BEC) - 3.7%; group C (moderate to heavy smoker with high BEC) - 73.8%; and group D (moderate to heavy smoker with low BEC) - 13.4%. Moderate to heavy smoker with high BEC group was oldest, and showed weak BDR response. Age, sex, BDR, comorbidities, and medications significantly differed among the four groups.

CONCLUSION

The prevalence of ACO differed between COPD and severe asthma cohorts. ACO patients can be classified into four phenotype groups, such that each phenotype exhibits distinct characteristics.

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.

Genetic Determinants in Airways Obstructive Diseases: The Case of Asthma Chronic Obstructive Pulmonary Disease Overlap

Genome-wide association studies (GWAS) of asthma and chronic obstructive pulmonary disease (COPD) with ever-increasing sample sizes have found multiple genetic loci associated with either disease. However, there are few intersecting loci between asthma and COPD. GWAS specifically focused on asthma-COPD overlap (ACO) have been limited by smaller sample sizes and the lack of a consistent definition of ACO that has also hampered clinical and epidemiologic studies. Other genomic techniques, such as gene expression profiling, are feasible with smaller sample sizes. Genetic analyses of objective measures of airway reactivity and allergy/T2 inflammation biomarkers in COPD studies may be another strategy to overcome limitations in ACO definitions.

[Take-home messages from the COPD 2021 biennial of the French Society of Respiratory Diseases. Understanding to so as to better innovate]

INTRODUCTION

The first COPD biennial organized by the French Society of Respiratory Diseases (SPLF) took place on 17 December 2021.

STATE OF THE ART

The objective of the biennial was to discuss current knowledge regarding COPD pathophysiology, current treatments, research development, and future therapeutic approaches.

PERSPECTIVES

The different lecturers laid emphasis on the complexity of pathophysiologic mechanisms including bronchial, bronchiolar and parenchymal alterations, and also dwelt on the role of microbiota composition in COPD pathenogenesis. They pointed out that addition to inhaled treatments, ventilatory support and endoscopic approaches have been increasingly optimized. The development of new therapeutic pathways such as biotherapy and cell therapy (stem cells…) call for further exploration.

CONCLUSIONS

The dynamism of COPD research was repeatedly underlined, and needs to be further reinforced, the objective being to "understand so as to better innovate" so as to develop effective new strategies for treatment and management of COPD.

Immunophenotyping of Acute Inflammatory Exacerbations of Lung Injury Driven by Mutant Surfactant Protein-C: A Role for Inflammatory Eosinophils

Acute inflammatory exacerbations (AIEs) represent immune-driven deteriorations of many chronic lung conditions, including COPD, asthma, and pulmonary fibrosis (PF). The first line of therapy is represented by broad-spectrum immunomodulation. Among the several inflammatory populations mobilizing during AIEs, eosinophils have been identified as promising indicators of an active inflammatory exacerbation. To better study the eosinophil-parenchymal crosstalk during AIE-PF, this work leverages a clinically relevant model of inflammatory exacerbations triggered by inducible expression of a mutation in the alveolar epithelial type 2 cell Surfactant Protein-C gene [SP-C^I73T]. Unbiased single-cell sequencing analysis of controls and SP-C^I73T mutants at a time coordinated with peak eosinophilia (14 days) defined heightened inflammatory activation, chemotaxis, and survival signaling (IL-6, IL-4/13, STAT3, Glucocorticoid Receptor, mTOR, and MYC) in eosinophils. To study the impact of eosinophils in inflammatory exacerbations, the SP-C^I73T line was crossed with eosinophil lineage deficient mice (GATA1^Δdbl) to produce the SP-C^I73TGATA1^KO line. Time course analysis (7-42 days) demonstrated improved lung histology, survival, and reduced inflammation in SP-C^I73TGATA1^KO cohorts. Spectral flow cytometry of tissue digests confirmed eosinophil depletion in GATA1^KO mice and the absence of a compensatory shift in neutrophils and immature monocyte recruitment. Eosinophil deletion resulted in progressive monocyte-derived macrophage accumulation (14 days post-injury), combined with declines in CD3⁺CD4⁺ lymphocyte and B220⁺ B cell abundance. Histochemical analysis revealed atypical inflammatory cell activation in SP-C^I73TGATA1^KO mice, with reduced numbers of Arg-1⁺ and iNOS⁺ cells, but increases in tgfb1 mRNA expression in bronchoalveolar lavage cells and tissue. Dexamethasone treatment (1 mg/kg daily, i.p.) was utilized to investigate corticosteroid efficacy in highly eosinophilic exacerbations induced by mutant SP-C^I73T. Dexamethasone successfully reduced total and eosinophil (CD11b⁺SigF⁺CD11c^-) counts at 14 days and was linked to reduced evidence of structural damage and perivascular infiltrate. Together, these results illustrate the deleterious role of eosinophils in inflammatory events preceding lung fibrosis and demonstrate the efficacy of corticosteroid treatment in highly eosinophilic exacerbations induced by mutant SP-C^I73T.

Common exacerbation-prone phenotypes across asthma and chronic obstructive pulmonary disease (COPD)

BACKGROUND AND OBJECTIVES

Chronic inflammatory airway diseases, including asthma and chronic obstructive pulmonary disease (COPD), are complex syndromes with diverse clinical symptoms due to multiple pathophysiological conditions. In this study, using common and shared risk factors for the exacerbation of asthma and COPD, we sought to clarify the exacerbation-prone phenotypes beyond disease labels, and to specifically investigate the role of the IL4RA gene polymorphism, which is related to type 2 inflammation, in these exacerbation-prone phenotypes.

METHODS

The study population comprised patients with asthma (n = 117), asthma-COPD overlap (ACO; n = 37) or COPD (n = 48) and a history of exacerbation within the previous year. Cluster analyses were performed using factors associated with both asthma and COPD exacerbation. The association of the IL4RA gene polymorphism rs8832 with each exacerbation-prone phenotype was evaluated by multinomial logistic analyses using non-asthma non-COPD healthy adults as controls (n = 1,529). In addition, the genetic influence of rs8832 was also examined in asthma patients with allergic rhinitis and no history of exacerbation (n = 130).

RESULTS

Two-step cluster analyses identified five clusters that did not necessarily correspond to the diagnostic disease labels. Cluster 1 was characterized by high eosinophil counts, cluster 2 was characterized by smokers with impaired lung function, cluster 3 was characterized by the presence of gastroesophageal reflux, cluster 4 was characterized by non-allergic females, and cluster 5 was characterized by allergic rhinitis and elevated total immunoglobulin E levels. A significant association with rs8832 was observed for cluster 5 (odds ratio, 3.88 (1.34-11.26), p = 0.013) and also for the type 2 exacerbation-prone phenotypes (clusters 1 and 5: odds ratio, 2.73 (1.45-5.15), p = 1.9 × 10-3).

DISCUSSION

Our results indicated that the clinical heterogeneity of disease exacerbation may reflect the presence of common exacerbation-prone endotypes across asthma and COPD, and may support the use of the treatable traits approach for the prevention of exacerbations in patients with chronic inflammatory airway diseases.

Acute iron oxide nanoparticles exposure induced murine eosinophilic airway inflammation via TLR2 and TLR4 signaling

Iron oxide nanoparticles (Fe₂ O₃ NPs) is the main component of air pollution particles in urban rail transit environment. People are more exposed to Fe₂ O₃ NPs, however, the studies on relationship between Fe₂ O₃ NPs and respiratory health are limited. In the present study, acute airway inflammation caused by Fe₂ O₃ NPs and its possible mechanism were investigated. BALB/c mice were intratracheally challenged with different concentrations of Fe₂ O₃ NPs. Fe₂ O₃ NPs induced bronchial epithelial barrier function damage, infiltration of neutrophils and lymphocytes into the airway submucosa, secretion of mucus in the airway epithelium and elevated expression of eosinophil major basic protein (EMBP) in lungs. Compared with the control group, Fe₂ O₃ NPs increased eosinophils by 20 times in bronchoalveolar lavage fluid (BALF), and markedly increased eosinophils related cytokines and chemokines, including interleukin (IL) -5, IL-33, thymic stromal lymphopoietin (TSLP), monocyte chemotactic protein (MCP)-3, eotaxin, tumor necrosis factor (TNF)-α, keratinocyte chemoattractant (KC). Furthermore, Fe₂ O₃ NPs up-regulated levels of IL-5, MCP-3, eotaxin, and KC in serum. In vitro studies showed that Fe₂ O₃ NPs increased the genes and proteins expression of Toll-like receptors (TLR)-2, TLR4, TNF receptor associated factor 6 (TRAF6), myeloid differentiation factor 88 (MyD88), nuclear factor (NF)-κB, and TNF-α in RAW267.4 cells. The downstream inflammatory cytokine protein expression and release such as TNF-α was significantly decreased after using TLR2/TLR4 inhibitor OxPAPC, but not MyD88 inhibitor ST2825. These results suggest that TLR2 and TLR4 played important role in Fe₂ O₃ NPs inducing acute eosinophilic airway inflammation in the murine lung.

Chronic obstructive pulmonary disease and atherosclerosis: common mechanisms and novel therapeutics

Chronic obstructive pulmonary disease (COPD) and atherosclerosis are chronic irreversible diseases, that share a number of common causative factors including cigarette smoking. Atherosclerosis drastically impairs blood flow and oxygen availability to tissues, leading to life-threatening outcomes including myocardial infarction (MI) and stroke. Patients with COPD are most likely to die as a result of a cardiovascular event, with 30% of all COPD-related deaths being attributed to cardiovascular disease (CVD). Both atherosclerosis and COPD involve significant local (i.e. lung, vasculature) and systemic inflammation and oxidative stress, of which current pharmacological treatments have limited efficacy, hence the urgency for the development of novel life-saving therapeutics. Currently these diseases must be treated individually, with no therapies available that can effectively reduce the likelihood of comorbid CVD other than cessation of cigarette smoking. In this review, the important mechanisms that drive atherosclerosis and CVD in people with COPD are explained and we propose that modulation of both the oxidative stress and the inflammatory burden will provide a novel therapeutic strategy to treat both the pulmonary and systemic manifestations related to these diseases.

Longitudinal changes in forced expiratory volume in 1 s in patients with eosinophilic chronic obstructive pulmonary disease

BACKGROUND

Data on changes in lung function in eosinophilic chronic obstructive pulmonary disease (COPD) are limited. We investigated the longitudinal changes in forced expiratory volume in 1 s (FEV₁) and effects of inhaled corticosteroid (ICS) in Korean COPD patients.

METHODS

Stable COPD patients in the Korean COPD subgroup study (KOCOSS) cohort, aged 40 years or older, were included and classified as eosinophilic and non-eosinophilic COPD based on blood counts of eosinophils (greater or lesser than 300 cells/μL). FEV₁ changes were analyzed over a 3-year follow-up period.

RESULTS

Of 627 patients who underwent spirometry at least twice during the follow up, 150 and 477 patients were classified as eosinophilic and non-eosinophilic, respectively. ICS-containing inhalers were prescribed to 40% of the patients in each group. Exacerbations were more frequent in the eosinophilic group (adjusted odds ratio: 1.49; 95% confidence interval: 1.10-2.03). An accelerated FEV₁ decline was observed in the non-eosinophilic group (adjusted annual rate of FEV₁ change: - 12.2 mL/y and - 19.4 mL/y for eosinophilic and non-eosinophilic groups, respectively). In eosinophilic COPD, the adjusted rate of annual FEV₁ decline was not significant regardless of ICS therapy, but the decline rate was greater in ICS users (- 19.2 mL/y and - 4.5 mL/y, with and without ICS therapy, respectively).

CONCLUSIONS

The annual rate of decline in FEV₁ was favorable in eosinophilic COPD compared to non-eosinophilic COPD, and ICS therapy had no beneficial effects on changes in FEV₁.

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.

The Use of Inhaled Corticosteroids for Patients with COPD Who Continue to Smoke Cigarettes: An Evaluation of Current Practice

The use of inhaled corticosteroids (ICS) in combination with inhaled bronchodilators for patients with chronic obstructive pulmonary disease (COPD) is a common practice in primary care settings. However, ICS-containing therapies may be less effective in patients with COPD compared with asthma, and in individuals with COPD who continue to smoke cigarettes. Preclinical studies suggest that inflammation in COPD is very different from in asthma. Glucocorticoid receptor functioning and other innate anti-inflammatory mechanisms are altered in cells exposed to cigarette smoke. COPD may be relatively insensitive to ICS, especially in individuals who continue to smoke. ICS-containing therapies in patients with asthma who continue to smoke may also be less effective compared with patients who do not smoke. ICS-containing therapies may be inappropriately used in some patients with COPD, and their long-term use is associated with an increased risk for side effects, including pneumonia and bone fractures in some patients. Treatment for patients with COPD should be carefully evaluated, and anti-inflammatory/bronchodilatory strategies should be chosen based on individual patient characteristics and recommendations in current guidelines.

Blood Eosinophils in Chinese COPD Participants and Response to Treatment with Combination Low-Dose Theophylline and Prednisone: A Post-Hoc Analysis of the TASCS Trial

Background and Objectives

The burden of chronic obstructive pulmonary disease (COPD) disproportionately affects patients in low to middle-income countries. Although the Theophylline and Steroids in COPD Study (TASCS) showed no clinical benefit from administering low-dose theophylline and prednisone in COPD patients compared to placebo, it was hypothesized that those with elevated blood eosinophil counts would receive clinical benefit from the intervention.

Methods

This was a post-hoc analysis of the TASCS dataset – a double-blinded, placebo-controlled trial conducted in patients with moderate–severe COPD in China. Participants were allocated 1:1:1 to low-dose oral theophylline (100mg bd) and prednisone (5mg qd; PrT), theophylline (100mg bd) and prednisone-matched placebo (TP), or double-matched placebo (DP) groups and followed-up for 48 weeks. A baseline count of ≥300 eosinophils/µL blood was categorized as elevated/eosinophilic, and the primary outcome was the annualized moderate-severe exacerbation rate.

Results

Of 1487 participants eligible for analysis, 325 (22%) were eosinophilic. These participants were predominantly male (82%), had a mean (SD) age of 64 (±8) years and a predicted forced expiratory volume in 1s (FEV₁) of 43% (±16). The annualized moderate–severe exacerbation rate was significantly higher in the PrT group compared to the pooled results of the TP and DP groups (incidence rate ratio = 1.6; ([95% CI 1.06–1.76]) p = 0.016). Changes in spirometry values and reported disease impact scores (St. George’s Respiratory Questionnaire and COPD Assessment Test) at week 48 were not significantly different between groups.

Conclusion

Combination low-dose theophylline and prednisone was associated with a significant increase in the annual moderate-severe exacerbation rate in participants with a blood eosinophil count ≥300 cells/µL compared to placebo.

The Heterogeneity of Inflammatory Response and Emphysema in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease characterized by chronic inflammation, emphysema, airway remodeling, and altered lung function. Despite the canonical classification of COPD as a neutrophilic disease, blood and airway eosinophilia are found in COPD patients. Identifying the tools to assess eosinophilic airway inflammation in COPD models during stable disease and exacerbations will enable the development of novel anti-eosinophilic treatments. We developed different animal models to mimic the pathological features of COPD. Our results show that eosinophils accumulated in the lungs of pancreatic porcine elastase-treated mice, with emphysema arising from the alveolar septa. A lipopolysaccharide challenge significantly increased IL-17 levels and induced a swift change from a type-2 response to an IL-17-driven inflammatory response. However, lipopolysaccharides can exacerbate cigarette smoking-induced airway inflammation dominated by neutrophil infiltration and airway remodeling in COPD models. Our results suggest that eosinophils may be associated with emphysema arising from the alveolar septa, which may be different from the small airway disease-associated emphysema that is dominated by neutrophilic inflammation in cigarette smoke-induced models. The characterization of heterogeneity seen in the COPD-associated inflammatory signature could pave the way for personalized medicine to identify new and effective therapeutic approaches for COPD.

Racial Differences in Prevalence and Clinical Characteristics of Asthma-Chronic Obstructive Pulmonary Disease Overlap

Background: This study examined the differences in the prevalence and clinical features of asthma–chronic obstructive pulmonary disease (COPD) overlap (ACO) with identical diagnostic criteria by race and ethnicity in two nationwide cohorts of COPD.

Methods: We used data from the Korean COPD Subgroup Study (KOCOSS) and phase I of the US Genetic Epidemiology of COPD (COPDGene) study. We defined ACO by satisfying bronchodilator response (BDR) >15% and 400 ml and/or blood eosinophil count ≥300/μl.

Results: The prevalences of ACO according to ethnicity were non-Hispanic white (NHW), 21.4%; African American (AA), 17.4%; and Asian, 23.8%. Asian patients with ACO were older, predominantly male, with fewer symptoms, more severe airflow limitation, and fewer comorbidities than NHW and AA patients. During 1-year follow-up, exacerbations occurred in 28.2, 22.0, and 48.4% of NHW, AA, and Asian patients with ACO, respectively. Compared to patients with non-ACO from the same racial group, the risk for exacerbation was significantly higher in NHW and Asian patients with ACO [adjusted incident rate ratio (aIRR), 1.17; 95% CI, 1.01–1.36, and aIRR, 1.37; 95% CI, 1.09–1.71 for NHW and Asian patients with ACO, respectively]. Inhaled corticosteroid (ICS) reduced the risk for future exacerbation in total patients with ACO but the effect was not significant in each racial group.

Conclusions: The prevalence of ACO was similar in the two cohorts using the same diagnostic criteria. The risk for future exacerbation was significantly higher in ACO, and the use of ICS reduced the risk for exacerbation in total patients with ACO.

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.

Blood Eosinophils and Pulmonary Rehabilitation in COPD

Background

Blood eosinophils predict the response to therapy, risk of exacerbation, and readmission in COPD. This study investigates whether blood eosinophils predict pulmonary rehabilitation (PR) outcomes in COPD.

Methods

We categorized patients into eosinophilic (blood eosinophils ≥300 cells/ml) or noneosinophilic (<300 cells/ml). In a retrospective design, we compared changes within and between the two groups on BODE index, 6-minute walk test (6MWT), FEV1, and mMRC dyspnea scale.

Results

Of 206 patients enrolled, 176 were included for analysis; 90 were eosinophilic. BODE index improved in both groups: (MD -1.25; 95% CI (-0.45, -4.25), P ≤ 0.001) in the eosinophilic and (MD -1.33; 95% CI (-1.72, -0.94), P ≤ 0.001) in the noneosinophilic, but a higher BODE index remained in the eosinophilic (4.98); adjusted mean change (β): 0.7 (95% CI (0.15, 1.26), P=0.01). 6MWT improved by 29.3 m in the eosinophilic (95% CI (14.2, 44.4), P ≤ 0.001) vs. 115.1 m in the noneosinophilic (95% CI (-30.4, 260.6), P=0.12). FEV1 did not change in the eosinophilic (MD -0.6; 95% CI (-2.64, 1.48), P=0.58), but improved by 2.5% in the noneosinophilic (MD 2.5; 95% CI (0.77, 4.17), P=0.005). There were no significant between-group differences in 6MWT and FEV1; adjusted mean changes (β) were -9.69 m (95% CI (-39.51, 20.14), P=0.52) and -2.31% (95% CI (-5.69, 1.08), P=0.18), respectively. There were no significant within- or between-group changes in the mMRC scale.

Conclusion

Although PR improves the BODE index in both eosinophilic and noneosinophilic COPD, a higher eosinophil count (≥300 cells/ml) is associated with a higher (worse) BODE index. Blood eosinophils may predict PR outcomes.