The association between eosinophilic exacerbation and eosinophilic levels in stable COPD

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Prediction value of neutrophil and eosinophil count at risk of COPD exacerbation

INTRODUCTION

Predicting acute exacerbations (AEs) in chronic obstructive pulmonary disease (COPD) is crucial. This study aimed to identify blood biomarkers for predicting COPD exacerbations by inflammatory phenotypes.

MATERIALS AND METHODS

We analyzed blood cell counts and clinical outcomes in 340 COPD patients aged 20-90 years. Patients were categorized into eosinophilic inflammation (EOCOPD) and non-eosinophilic inflammation (N-EOCOPD) groups. Blood cell counts, eosinophil-to-lymphocyte ratio (ELR), neutrophil-to-lymphocyte ratio (NLR) and neutrophil-to-eosinophil ratio (NER) were calculated. Linear and logistic regression models assessed relationships between health outcomes and blood cell counts.

RESULTS

EOCOPD patients had distinct characteristics compared to N-EOCOPD patients. Increased neutrophil % and decreased lymphocyte % were associated with reduced pulmonary function, worse quality of life and more exacerbations, but they did not show statistical significance after adjusting by age, sex, BMI, smoking status, FEV1% and patient's medication. Subgroup analysis revealed a 1.372-fold increase in the OR of AE for every 1 unit increase in NLR in EOCOPD patients (p < .05). In N-EOCOPD patients, every 1% increase in blood eosinophil decreased the risk of exacerbation by 59.6%.

CONCLUSIONS

Our study indicates that distinct white blood cell profiles in COPD patients, with or without eosinophilic inflammation, can help assess the risk of AE in clinical settings.

Development and Validation of Prediction Models for Exacerbation, Frequent Exacerbations and Severe Exacerbations of Chronic Obstructive Pulmonary Disease: A Registry Study in North China

In COPD patients, exacerbation has a detrimental influence on the quality of life, disease progression and socioeconomic burden. This study aimed to develop and validate models to predict exacerbation, frequent exacerbations and severe exacerbations in COPD patients. We conducted an observational prospective multicenter study. Clinical data of all outpatients with stable COPD were collected from Beijing Chaoyang Hospital and Beijing Renhe Hospital between January 2018 and December 2019. Patients were followed up for 1 year. The data from Chaoyang Hospital was used for modeling dataset, and that of Renhe Hospital was used for external validation dataset. The final dataset included 456 patients, with 326 patients as the model group and 130 patients as the validation group. Using LABA + ICS, frequent exacerbations in the past year and CAT score were independent risk factors for exacerbation in the next year (OR = 2.307, 2.722 and 1.147), and FVC %pred as a protective factor (OR = 0.975). Combined with chronic heart failure, frequent exacerbations in the past year, blood EOS counts and CAT score were independent risk factors for frequent exacerbations in the next year (OR = 4.818, 2.602, 1.015 and 1.342). Using LABA + ICS, combined with chronic heart failure, frequent exacerbations in the past year and CAT score were independent risk factors for severe exacerbations in the next year (OR = 1.950, 3.135, 2.980 and 1.133). Based on these prognostic models, nomograms were generated. The prediction models were simple and useful tools for predicting the risk of exacerbation, frequent exacerbations and severe exacerbations of COPD patients in North China.

COPD Exacerbation Syndrome: The Spanish Perspective on an Old Dilemma

The definition of exacerbation of COPD as a syndrome, as proposed by the Spanish COPD guidelines (GesEPOC) 2021 update, and the consequences that this implies, have direct implications on patient care. This review analyzes this novel vision of the COPD exacerbation syndrome, its rationale, and its clinical implications, as opposed to the traditional symptoms-based or event-based definitions. An exacerbation conceived as a syndrome provides us with an umbrella term to include a set of diverse alterations, which, either in isolation or more frequently in combination, are clinically expressed in a similar way in patients with COPD. In patients with COPD, this occurs as a consequence of worsening expiratory airflow limitation or the underlying inflammatory process, producing a worsening in symptoms with respect to the baseline situation. This definition therefore assumes a worsening in at least one of the two key physiopathological markers, lung function and inflammation. The main features of this new physiopathological proposal include a syndromic approach with narrower differential diagnosis, the use of several biomarkers, treatable traits to better guide treatment, and a new severity classification. Further research is needed to examine the role of eosinophils in this context, but currently, the early results are promising. The evaluation of severity is key in the multidimensional characterization of exacerbation and the GesEPOC 2021 proposes new approaches and also recommends the use of multidisciplinary scores for severity categorization in patients. Finally, another innovation in the GesEPOC 2021 refers to the recurrence of exacerbations, which has implications for disease prognosis or long-term clinical impact which need to be elucidated in further studies.

Using inflammatory index to distinguish asthma, asthma-COPD overlap and COPD: A retrospective observational study

BACKGROUND

Although asthma and chronic obstructive pulmonary disease (COPD) are two well-defined and distinct diseases, some patients present combined clinical features of both asthma and COPD, particularly in smokers and the elderly, a condition termed as asthma-COPD overlap (ACO). However, the definition of ACO is yet to be established and clinical guidelines to identify and manage ACO remain controversial. Therefore, in this study, inflammatory biomarkers were established to distinguish asthma, ACO, and COPD, and their relationship with the severity of patients' symptoms and pulmonary function were explored.

MATERIALS AND METHODS

A total of 178 patients, diagnosed with asthma (n = 38), ACO (n = 44), and COPD (n = 96) between January 2021 to June 2022, were enrolled in this study. The patients' pulmonary function was examined and routine blood samples were taken for the analysis of inflammatory indexes. Logistic regression analysis was used to establish inflammatory biomarkers for distinguishing asthma, ACO, and COPD; linear regression analysis was used to analyze the relationship between inflammatory indexes and symptom severity and pulmonary function.

RESULT

The results showed that, compared with ACO, the higher the indexes of platelet, neutrophil-lymphocyte ratio (NLR) and eosinophil-basophil ratio (EBR), the more likely the possibility of asthma and COPD in patients, while the higher the eosinophils, the less likely the possibility of asthma and COPD. Hemoglobin and lymphocyte-monocyte ratio (LMR) were negatively correlated with the severity of patients' symptoms, while platelet-lymphocyte ratio (PLR) was negatively correlated with forced expiratory volume in the 1 s/forced vital capacity (FEV1/FVC) and FEV1 percent predicted (% pred), and EBR was positively correlated with FEV1% pred.

CONCLUSION

Inflammatory indexes are biomarkers for distinguishing asthma, ACO, and COPD, which are of clinical significance in therapeutic strategies and prognosis evaluation.

Phenotyping acute exacerbation of COPD: what more can we do for hospitalised patients?

Hospitalised #AECOPD are characterised by multiple facets of aetiology. The clinical interpretation of the composite phenotypes of AECOPD and the robustness of the AECOPD phenotype need to be discussed further. https://bit.ly/3grzQEO.

The influence of individual characteristics and non-respiratory diseases on blood eosinophil count

Background

Blood eosinophil (B-Eos) count is an emerging biomarker in the management of respiratory disease but determinants of B-Eos count besides respiratory disease are poorly described. Therefore, we aimed to evaluate the influence of non-respiratory diseases on B-Eos count, in comparison to the effect on two other biomarkers: fraction of exhaled nitric oxide (FeNO) and C-reactive protein (CRP), and to identify individual characteristics associated with B-Eos count in healthy controls.

Methods

Children/adolescents (<18 years) and adults with complete B-Eos data from the US National Health and Nutritional Examination Surveys 2005-2016 were included, and they were divided into having respiratory diseases (n = 3333 and n = 7,894, respectively) or not having respiratory disease (n = 8944 and n = 15,010, respectively). After excluding any respiratory disease, the association between B-Eos count, FeNO or CRP, and non-respiratory diseases was analyzed in multivariate models and multicollinearity was tested. After excluding also non-respiratory diseases independently associated with B-Eos count (giving healthy controls; 8944 children/adolescents and 5667 adults), the independent association between individual characteristics and B-Eos count was analyzed.

Results

In adults, metabolic syndrome, heart disease or stroke was independently associated with higher B-Eos count (12%, 13%, and 15%, respectively), whereas no associations were found with FeNO or CRP. In healthy controls, male sex or being obese was associated with higher B-Eos counts, both in children/adolescents (15% and 3% higher, respectively) and adults (14% and 19% higher, respectively) (p < 0.01 all). A significant influence of race/ethnicity was also noted, and current smokers had 17% higher B-Eos count than never smokers (p < 0.001).

Conclusions

Non-respiratory diseases influence B-Eos count but not FeNO or CRP. Male sex, obesity, certain races/ethnicities, and current smoking are individual characteristics or exposures that are associated with higher B-Eos counts. All these factors should be considered when using B-Eos count in the management of respiratory disease.