Eosinophils in COPD Exacerbations Are Associated With Increased Readmissions

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

BACKGROUND

Eosinophilic airway inflammation in patients with chronic obstructive pulmonary disease (COPD) is associated with exacerbations and responsivity to steroids, suggesting potential shared mechanisms with eosinophilic asthma. However, there is no consistent blood eosinophil count that has been used to define the increased exacerbation risk.

OBJECTIVE

We sought to investigate blood eosinophil counts associated with exacerbation risk in patients with COPD.

METHODS

Blood eosinophil counts and exacerbation risk were analyzed in patients with moderate-to-severe COPD by using 2 independent studies of former and current smokers with longitudinal data. The Genetic Epidemiology of COPD (COPDGene) study was analyzed for discovery (n = 1,553), and the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study was analyzed for validation (n = 1,895). A subset of the ECLIPSE study subjects were used to assess the stability of blood eosinophil counts over time.

RESULTS

COPD exacerbation risk increased with higher eosinophil counts. An eosinophil count threshold of 300 cells/μL or greater showed adjusted incidence rate ratios for exacerbations of 1.32 in the COPDGene study (95% CI, 1.10-1.63). The cutoff of 300 cells/μL or greater was validated for prospective risk of exacerbation in the ECLIPSE study, with adjusted incidence rate ratios of 1.22 (95% CI, 1.06-1.41) using 3-year follow-up data. Stratified analysis confirmed that the increased exacerbation risk associated with an eosinophil count of 300 cells/μL or greater was driven by subjects with a history of frequent exacerbations in both the COPDGene and ECLIPSE studies.

CONCLUSIONS

Patients with moderate-to-severe COPD and blood eosinophil counts of 300 cells/μL or greater had an increased risk exacerbations in the COPDGene study, which was prospectively validated in the ECLIPSE study.

Blood eosinophil count and risk of pneumonia hospitalisations in individuals with COPD

Blood eosinophil count in chronic obstructive pulmonary disease (COPD) is associated with higher exacerbation rate and favourable response to corticosteroids; however, frequent exacerbations and use of inhaled corticosteroids could elevate pneumonia risk. We tested the hypothesis that high blood eosinophil counts are associated with high risk of pneumonia in individuals with severe COPD from the general population.

We included 7180 individuals with COPD from the Copenhagen General Population Study, including 643 with forced expiratory volume in 1 s (FEV1) <50% predicted between 2003 and 2011. All primary discharge diagnoses of pneumonia during follow-up were recorded.

Among individuals with COPD and FEV1<50% pred, the multivariable adjusted incidence rate ratio was 2.17 (95% CI 1.31–3.58) for pneumonia comparing individuals with blood eosinophil counts ≥0.34×109 cells·L−1versus<0.34×109 cells·L−1. In individuals with clinical COPD, defined by recent exacerbation, ≥10 pack-years of smoking and FEV1<70% pred, the corresponding risk was 4.52 (2.11–9.72). Risk of pneumonia did not differ by blood eosinophil count in individuals with COPD and FEV1≥50% pred.

In individuals with COPD and FEV1<50% pred, blood eosinophil count ≥0.34×109 cells·L−1was associated with high risk of hospitalisation due to pneumonia.

COPD 2017: A Year in Review

In this review, we focused on original manuscripts published in the 2017 that provided additional information on the clinical and therapeutic features of the chronic obstructive pulmonary disease (COPD). We have chosen eight of these studies, collected in four topics concerning the pharmacological treatment (tiotropium) of mild-moderate patients, the pharmacological (fluticasone furoate/vilanterol/umeclidinium) and non-pharmacological treatment (non-invasive mechanical ventilation) of severe patients, the etiology of acute exacerbation of COPD involving seasonal airway pathogens and the role of eosinophils with particular interest to the monoclonal antibody directed against interleukin-5 (mepolizumab). For each topic, we report a brief description of studies, take-home messages, and brief comments.

Risk factors for respiratory hospitalizations in a population of patients with a clinical diagnosis of COPD

Purpose

The purpose of this study was to examine differences between patients clinically diagnosed with COPD with and without obstruction by spirometry and to identify risk factors for respiratory hospitalizations.

Materials and methods

This is a retrospective analysis of all patients diagnosed with COPD at a large academic Internal Medicine Clinic in 2014, who had spirometry performed during the period 2013–2014. Two groups existed: one with obstruction termed classical COPD and another without obstruction. Demographics, comorbidities, prescribed medications, spirometry, respiratory hospitalization, and eosinophilia among other variables were compared between patients with and without obstruction. Risk factors for two or more respiratory hospitalizations during the period 2014–2015 were sought for both populations by both univariate and multivariate analyses. Subsequently, we studied the population without obstruction for risk factors for one or more respiratory hospitalizations first by univariate analysis and then by multivariate analysis.

Results

Among 657 patients, 210 met inclusion criteria, with 157 having obstruction on spirometry and 53 without obstruction. There was no difference between those with and without obstruction on the rate of respiratory hospitalization when using two or more respiratory hospitalizations (p=0.397) or one or more respiratory hospitalizations (p=0.467). Nontreatment risk factors associated with two or more respiratory hospitalizations by multivariate analysis included a maximum eosinophil count above the threshold of 0.5 K/µL (maximum eosinophil number threshold [MENT]; p=0.001, OR =3.792, 95% CI =1.676–8.582) and % predicted forced expiratory volume in the first second (p=0.031, OR =0.978, 95% CI =0.959–0.998). In patients without obstruction, MENT above the threshold of 0.5 K/µL (p=0.032, OR =5.087, 95% CI =1.147–22.557) was the only risk factor associated with one or more respiratory hospitalizations.

Conclusion

In a clinically diagnosed COPD population who had spirometry performed, the presence of airflow obstruction was not a risk factor for respiratory hospitalizations. The most significantly associated nontreatment factor associated with respiratory hospitalization, both in the study population as a whole and in the cohort without obstruction, was MENT above the threshold of 0.5 K/µL.

Evaluation of Systemic Corticosteroids in Patients With an Acute Exacerbation of COPD and a Diagnosis of Pneumonia

Background: Chronic obstructive pulmonary disease (COPD) and pneumonia are leading causes of morbidity and mortality and are frequently comorbid. Studies of systemic corticosteroids in pneumonia have shown conflicting outcomes, whereas studies in acute exacerbations of COPD (AECOPD) have shown significant benefits. No studies have evaluated systemic corticosteroids in patients with both an AECOPD and pneumonia. Purpose: To evaluate the use of systemic corticosteroids in patients with both an AECOPD and pneumonia. Patients and Methods: Patients with a diagnosis of both COPD or obstructive chronic bronchitis with exacerbation and pneumonia admitted to the University of Colorado Hospital between July 1, 2012 and May 20, 2016 were retrospectively evaluated. Patients who received systemic corticosteroids were compared to those that did not. The primary outcome was length of hospital stay (LOHS). Secondary outcomes were in-hospital treatment failure, a composite of intensive care unit (ICU) admission, ventilation, and escalation of steroid therapy, 30-day AECOPD or pneumonia readmission, and 30-day mortality. Results: A total of 138 patients were included-- 89 in the steroid group and 49 in the non-steroid group. No significant differences in baseline characteristic were noted. No difference was seen in mean LOHS (4.7±3.2 versus 4.2±2.1 days, p=0.27), in-hospital treatment failure (7% versus 4%, p=0.72), 30-day readmission or 30-day mortality between the steroid and non-steroid groups, respectively. There was a difference in mean LOHS for patients with severe pneumonia between the steroid and non-steroid groups (6.0±4.0 versus 4.3±1.8; p=0.03). Conclusions: This study suggests that systemic corticosteroids may not provide a clinical benefit to patients with an AECOPD and pneumonia.

Persistently elevated exhaled nitric oxide fraction is associated with increased risk of exacerbation in COPD

Preventing the occurrence of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is a major therapeutic goal. We hypothesise that persistently increased levels of exhaled nitric oxide (F_eNO) during follow-up can identify a group of COPD patients at higher risk of AECOPD.To test this hypothesis, we measured F_eNO levels (HypAir F_eNO®, Medisoft; Sorinnes, Belgium) prospectively in 226 clinically stable COPD outpatients at recruitment and during follow-up (at 6 and 12 months). Patients were stratified according to the number of visits with F_eNO ≥20 ppb.F_eNO was <20 ppb in all three visits in 44.2% of patients, 29.6% in visit 1 and 26.1% in visit 2 or 3. These three groups suffered progressively higher AECOPD rates during follow-up (0.67, 0.91 and 1.42, respectively, p<0.001). After adjusting for potential confounding variables (log-rank test), the hazard ratio for AECOPD was higher in the latter group (1.579 (95% CI 1.049-2.378), p=0.029). Likewise, time to first moderate and severe AECOPD was shorter in these patients. Finally, there was no relationship between F_eNO levels and circulating eosinophils.Persistent F_eNO levels ≥20 ppb in clinically stable COPD outpatients are associated with a significantly higher risk of AECOPD.

Blood biomarkers as predictors of long-term mortality in COPD

BACKGROUND

Blood biomarkers are easily accessible and might reflect chronic obstructive pulmonary disease (COPD) activity.

AIM

The aim of this study was to determine whether a panel of blood biomarkers [C-reactive protein (CRP), neutrophils, eosinophils, albumin and vitamin D] could predict mortality in COPD.

METHODS

We analyzed data from 431 COPD participants to the 2007-2010 National Health and Nutrition Examination Surveys who were followed for a median time of 36 months. COPD was defined as post-bronchodilator forced expiratory volume in 1 second (FEV1) and forced vital capacity ratio <0.70. Weibull survival analysis adjusted for covariates was performed to calculate the risk of mortality associated with the biomarkers, and C-statistics was used to assess their added predictive value.

RESULTS

During follow-up, 38 of the 431 participants died. Participants with high CRP, eosinophil count <2%, hypoalbuminemia and hypovitaminosis D had worse baseline FEV1 and subsequently higher mortality compared to controls. In adjusted analysis, increasing CRP [hazard ratio (HR): 4.45, 95% CI: 1.91-10.37] and neutrophil count (HR: 1.07, 95% CI: 1.03-1.11) as well as decreasing eosinophil count (HR: 7.03, 95% CI: 2.05-24.01) were associated with an increased risk of mortality. The addition of CRP with eosinophil and/or neutrophil count significantly improved a base model for the prediction of mortality which included age, gender, race/ethnicity, body mass index, smoking, poverty income ratio, asthma, diabetes, hypertension and history of stroke or myocardial infarction.

CONCLUSION

High CRP and neutrophils as well as low eosinophils are predictive of poor COPD prognosis. They also add significant value to prediction models of mortality in COPD.

2017 Global Initiative for Chronic Obstructive Lung Disease reclassifies half of COPD subjects to lower risk group

Background

Unlike the 2014 guidelines, the 2017 Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines have removed lung function from the risk assessment algorithm of patients with COPD. The aim of this investigation was to analyze the proportion of subjects who would change to a lower risk group when applying GOLD²⁰¹⁷ and determine if they exhibit different characteristics in terms of inflammation, symptoms and comorbidity compared to the subjects who would remain in a high-risk group.

Subjects and methods

A total of 571 subjects with physician-diagnosed and spirometry-verified COPD were included in the present study. The data consisted of measurements of lung function, inflammatory markers, together with questionnaires that covered comorbidities, COPD symptoms and medication.

Results

From group C, 53% of the subjects would be reclassified to the lower risk group A, and from group D, 47% of the subjects would be reclassified to the lower risk group B when using GOLD²⁰¹⁷ instead of GOLD²⁰¹⁴. Compared to the subjects who would remain in group D, those who would change to group B were more often men (56% vs 72%); of an older age, mean (SD), 71 (8) years vs 68 (7) years; had more primary care contact (54% vs 33%); had lower levels of blood neutrophils, geometrical mean (95% CI), 5.3 (5.0, 5.7) vs 4.6 (4.3, 4.9); reported less anxiety/depression (20% vs 34%); experienced less asthma (29% vs 46%) and had fewer symptoms according to the COPD assessment test, 16 (5) vs 21 (7). All p-values were <0.05.

Conclusion

The removal of spirometry from risk assessment in GOLD²⁰¹⁷ would lead to the reclassification of approximately half of the subjects in the risk groups C and D to the lower risk groups A and B. There are differences in age, gender, health care contacts, inflammation, comorbidity and symptom burden among those changing from group D to group B. The effects of reclassification and changes in eventual treatment for disease control and symptom burden need further investigation.

Eosinophilia and clinical outcome of chronic obstructive pulmonary disease: a meta-analysis

Numerous studies have investigated the association between eosinophilia and clinical outcome of patients with chronic obstructive pulmonary disease (COPD) but the evidence is conflicting. We conducted a pooled analysis of outcome measures comparing eosinophilic and non-eosinophilic COPD patients. We searched articles indexed in four databases using Medical Subject Heading or Title and Abstract words including COAD, COPD, eosinophil, eosinophilia, eosinopenia from inception to December 2016. Observational studies and randomized controlled trials with parallel groups comparing COPD patients with and without eosinophilia were included. Comparing to the non-eosinophilic group, those with eosinophilic COPD had a similar risk for exacerbation in 12 months [Odds ratio = 1.07, 95% confidence interval (CI) 0.86–1.32, P = 0.55] and in-hospital mortality [OR = 0.52, 95% CI 0.25–1.07]. Eosinophilia was associated with reduced length of hospital stay (P = 0.04). Subsequent to therapeutic interventions, eosinophilic outpatients performed better in pulmonary function tests [Mean Difference = 1.64, 95% CI 0.05–3.23, P < 0.001]. Inclusion of hospitalized patients nullified the effect. Improvement of quality of life was observed in eosinophilic subjects [Standardized Mean Difference = 1.83, 95% CI 0.02–3.64, P = 0.05], independent of hospitalization status. In conclusion, blood eosinophilia may be predictive of favorable response to steroidal and bronchodilator therapies in patients with stable COPD.

Blood eosinophilia as a marker of early and late treatment failure in severe acute exacerbations of COPD

BACKGROUND

Blood eosinophilia is frequently encountered in patients with AECOPD. However the impact of blood eosinophilia at admission in patients with AECOPD on outcome on the short and long term has not been extensively studied which was the objective of the present study.

METHODS

We used data of 207 exacerbations from a randomized clinical trial on antibiotic prescription based upon CRP-levels versus GOLD guided strategy and analyzed the impact of blood eosinophils (≥2% of total white cell count and eosinophil count ≥300 cell/microliter) on clinical outcome.

RESULTS

207 patients were included of whom 39 (18·8%) had eosinophilia ≥2%, 23 patients (11.1%) had blood eosinophil ≥300 cell/microliter. Eosinophilia was associated with shorter median length of stay in the eosinophilic groups(≥2% and ≥300 cell/microliter) compared to the non-eosinophilic groups. Early treatment failure was reduced in the both the eosinophilic groups (≥2% and ≥300 cell/microliter). Late treatment failure (day 11-30) did not differ between the groups. Relapse, was more frequent the eosinophilic groups (≥2% and ≥300 cell/microliter), however in the latter group this did not reach statistical significance. Eosinophilia ≥2% was a risk factor for having relapse (eosinophilia ≥2%: HR = 2·351; 95%CI 1·335-4·139), whereas eosinophilia <2% was associated with a lower risk factor for having early treatment failure (HR = 0·339 95%CI 0·122-0·943).

CONCLUSION

We showed that blood eosinophilia at admission in patients with an AECOPD is associated with higher short-term treatment success rate. However, blood eosinophilia ≥2% predicts a less favorable outcome due to an increased risk of relapse.

CLINICAL TRIAL REGISTRATION

NCT01232140.

Eosinophils in COPD: just another biomarker?

Eosinophils are innate immune cells that, under certain conditions, can be recruited to the lungs, where they have an incompletely understood role in health and disease. Eosinophils have been found in the airways, tissues, and circulation of patients with COPD, during both stable disease and exacerbations. Epidemiological studies and post-hoc analyses of clinical trials of corticosteroid treatment for COPD have shown that the blood eosinophil count is associated with the risk of COPD exacerbations, mortality, decline in FEV₁, and response to both inhaled and systemic corticosteroids. Further studies are urgently needed to explore the contribution of eosinophils to the mechanism of disease in COPD and to identify their association with levels of clinical risk. In this review, we explore the role of the eosinophil as a biomarker and mediator of disease in COPD.

New Anti-Eosinophil Drugs for Asthma and COPD: Targeting the Trait!

Asthma and COPD are prevalent chronic inflammatory airway diseases that are responsible for a large global disease burden. Both diseases are complex and heterogeneous, and they are increasingly recognized as overlapping syndromes that may share similar pathophysiologic mechanisms and treatable traits. Eosinophilic airway inflammation is considered the most influential treatable trait of chronic airway disease, and over the last decade, several monoclonal antibodies and small molecule therapies have been developed to target this trait. These include monoclonal antibodies against IL-5 or IL-5 receptor alpha (mepolizumab, reslizumab, and benralizumab), IL-13 (lebrikizumab and tralokinumab), IL-4 receptor alpha (dupilumab), IgE (omalizumab), and anti-thymic stromal lymphopoietin (tezepelumab) and small molecule therapies such as prostaglandin D₂ blockers (fevipiprant and timapiprant). Although these novel biologic agents have shown promising results in many patients with asthma and COPD who have eosinophilic airway inflammation, it is evident that not all patients respond equally well, despite similar clinical, functional, and inflammatory characteristics. This heterogeneity in treatment response is probably related to different molecular pathways or endotypes leading to eosinophilic airway inflammation, including adaptive immune pathways mediated by T helper 2 cells and innate immune pathways mediated by innate lymphoid cells. The relative contribution of these pathways in asthma and COPD is not yet clarified, and there are currently no reliable biomarkers that represent the various pathways. Therefore, there is an urgent need for easily measurable and reproducible biomarkers that are linked to underlying pathophysiologic disease mechanisms and can predict and monitor responses to novel biologic agents.

Factors associated with plasma IL-33 levels in patients with chronic obstructive pulmonary disease

BACKGROUND

Interleukin (IL)-33 promotes T helper (Th)2 immunity and systemic inflammation. The role of IL-33 in asthma has been widely investigated. IL-33 has also been suggested to play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). This study investigated the clinical significance and usefulness of plasma IL-33 level in patients with COPD.

METHODS

A total of 307 patients with stable COPD from 15 centers, who were in the Korean Obstructive Lung Disease cohort, were enrolled in this study. Plasma IL-33 levels were measured by enzyme-linked immunosorbent assay. We analyzed the association between IL-33 level and other clinical characteristics related to COPD. We also examined the features of patients with COPD who exhibited high IL-33 levels.

RESULTS

IL-33 levels varied, but were very low in most patients. Eosinophil count was significantly correlated with a plasma IL-33 level. In addition, old age and current smoking were related to a low IL-33 level. Significantly more patients with a higher IL-33 level had chronic bronchitis compared with those with a low IL-33 level.

CONCLUSION

Plasma IL-33 level in patients with stable COPD was related to eosinophil count and chronic bronchitis phenotype. Further studies are needed to identify the precise mechanisms of IL-33/ST2 pathway in patients with COPD.