Stability of Blood Eosinophil Count in Patients with COPD in the UK Clinical Practice Research Datalink

Measurement of Blood Eosinophils in Asthma and Chronic Obstructive Pulmonary Disease

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

Identification of COPD Inflammatory Endotypes Using Repeated Sputum Eosinophil Counts

Higher blood and sputum eosinophil counts are associated with a greater response to corticosteroids in COPD. Low blood eosinophil counts exhibit greater stability over time whereas higher counts demonstrate more variability. Stability of airway eosinophil levels is less well understood. We have studied the stability of sputum eosinophil counts. Differential cell count data for COPD patients (n = 100) were analysed. Subjects with two sputum eosinophil counts, 6 months apart, were included in the analysis. Patients were stratified based on baseline sputum eosinophil count into ‘low’, ‘intermediate’ and ‘high’ groups: eosinophilLOW (<1%), eosinophilINT (1−3%) and eosinophilHIGH (≥3%). Sputum eosinophil counts showed good stability (rho = 0.61, p < 0.0001, ICC of 0.77), with 67.4% of eosinophilLOW patients remaining in the same category on repeat sampling. Bland−Altman analysis of the whole cohort (median difference between measurements = 0.00%, 90th percentile = −1.4 and 4.7%) showed greater variation at higher counts. This was confirmed by the wider 90th centiles in the eosinophilINT (−1.50 to 5.65) and eosinophilHIGH groups (−5.33 to 9.80) compared to the eosinophilLOW group (−0.40 to 1.40). The repeatability of sputum eosinophil counts was related to the baseline eosinophil count; sputum eosinophilLOW COPD patients were relatively stable over time, while the eosinophilHIGH group showed greater variability. These results can facilitate the identification of COPD endotypes with differential responses to treatment.

[COPD and eosinophils]

COPD is a major cause of morbidity and mortality worldwide. As research progresses, new patient phenotypes are being defined, providing hope for more personalized management of the disease. A significant proportion of patients present with an increased level of blood eosinophils, which may reflect bronchial eosinophilic inflammation. The aims of this article are to characterize the role of eosinophils in COPD in terms of pathophysiology, associated respiratory symptoms, impact on treatment and, finally, to consider different future treatment options.

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

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

Chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity, mortality, and health-care use worldwide. COPD is caused by exposure to inhaled noxious particles, notably tobacco smoke and pollutants. However, the broad range of factors that increase the risk of development and progression of COPD throughout the life course are increasingly being recognised. Innovations in omics and imaging techniques have provided greater insight into disease pathobiology, which might result in advances in COPD prevention, diagnosis, and treatment. Although few novel treatments have been approved for COPD in the past 5 years, advances have been made in targeting existing therapies to specific subpopulations using new biomarker-based strategies. Additionally, COVID-19 has undeniably affected individuals with COPD, who are not only at higher risk for severe disease manifestations than healthy individuals but also negatively affected by interruptions in health-care delivery and social isolation. This Seminar reviews COPD with an emphasis on recent advances in epidemiology, pathophysiology, imaging, diagnosis, and treatment.

Factors Influencing the Stability of Blood Eosinophils Counts in Chronic Obstructive Pulmonary Disease Patients

Blood eosinophil (EOS) has recently been recognized as a biomarker for chronic obstructive pulmonary disease (COPD) patients. However, few studies have concentrated on the stability of blood eosinophil counts (BEC), and those studies have produced varying results. With further research, we have found minor drawbacks and vulnerabilities that lead to the variability of the results. This paper enumerates several areas of relevant research with varying conclusions to further investigate the stability of BEC in COPD patients.

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

Introduction

Methods

Results

Conclusion

Narrative Literature Review Guided Approach of Inhaled Corticosteroid de-escalation in Chronic Obstructive Pulmonary Disease

OBJECTIVE

To review the 2020 Global Initiative for Chronic Obstructive Lung Disease (GOLD) report recommendations and create an algorithm to assist clinicians in determining which chronic obstructive pulmonary disease (COPD) patients qualify for inhaled corticosteroid (ICS) de-escalation. Data Sources: A literature search of MEDLINE/PubMed from 2002 to August 2021 was conducted using the search terms inhaled corticosteroids, chronic obstructive pulmonary disease, and de-escalation and review of the reference lists of identified articles for pertinent citations.

STUDY SELECTION AND DATA EXTRACTION

Relevant studies and articles were included if they focused on the utilization of ICS in COPD.

DATA SYNTHESIS

The 2020 GOLD report only recommends triple therapy with ICS, long acting beta agonists, and long acting muscarinic antagonists for patients with frequent exacerbations, frequent hospitalizations, or elevated blood eosinophil counts. Despite this clear framework, patients are prescribed ICS without these characteristics. Available evidence suggests that these patients can be de-escalated from ICS therapy without concern for worsening lung function or exacerbations. Relevance to Patient Care and Clinical Practice: Patients with COPD may be experiencing more risk than benefit on ICS therapy. Clinicians should be knowledgeable on how to evaluate patient therapy for appropriateness and know how to safely deprescribe ICS given their limited efficacy in many COPD patients.

CONCLUSION

There remains no specific guidance on how to de-escalate patients off an ICS when the therapy is not indicated. Use of clinical evidence with stepwise algorithms can be models to approach de-escalation of ICS in patients with COPD.

Neutrophil-to-lymphocyte ratio, blood eosinophils and COPD exacerbations: a cohort study

Background

Blood neutrophil-to-lymphocyte ratio (NLR) and blood eosinophils (B-Eos) are emerging biomarkers in COPD. This study examined whether they could predict acute exacerbations of COPD (AECOPDs), and determined their longitudinal stability.

Methods

In this closed cohort study, Swedish subjects with spirometry-verified COPD attended three yearly visits in a stable phase of the disease. Blood cell counts, spirometry and questionnaire-assessed AECOPD-history (worsening of COPD leading to an unscheduled visit and/or use of antibiotics and/or oral corticosteroids) were collected at each visit.

Results

Of 466 included subjects 57% were female. Baseline mean±sd forced expiratory volume in 1 s was 58±17% predicted. High NLR (≥3.0) was more common in subjects with previous AECOPDs than in those without (33.5% versus 20.4%, p=0.002). In two-level mixed-effects logistic regression models adjusted for confounders, NLR as a continuous variable (OR 1.20, 95% CI 1.04–1.38) and B-Eos ≥300 cells·µL⁻¹ (OR 1.54, 95% CI 1.06–2.24) were associated with future AECOPDs. In 386 subjects with blood cell data available at all three visits, the intraclass correlation coefficient for NLR was 0.61 (95% CI 0.56–0.66) and for B-Eos 0.69 (95% CI 0.64–0.73). NLR was persistently ≥3.0 in 10.6% and B-Eos was persistently ≥300 cells·µL⁻¹ in 15.3%.

Conclusions

Stable phase NLR and B-Eos were associated with future AECOPDs. NLR on its own is probably not useful to predict AECOPDs but might be included in a risk scoring index. A minority of subjects with COPD had persistently elevated stable-phase NLR or B-Eos, and the biomarkers showed fair longitudinal reliability.

Neutrophil-to-lymphocyte ratio and blood eosinophils in stable-phase COPD are associated with future exacerbations and show fair longitudinal reliabilityhttps://bit.ly/3CAS1jY

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Burden of illness in blood eosinophilic phenotype COPD patients in New Zealand

BACKGROUND

Real-world data on eosinophilic chronic obstructive pulmonary disease (COPD)'s clinical burden, in exacerbating/stable states, and the stability of blood eosinophil count (BEC) measurements are limited. We described measured BEC distributions among general practice COPD patients in New Zealand (NZ).

METHODS

This retrospective cohort study utilized the NZ-HealthStat primary care database. Participants were aged ≥40 years, with ≥1 BEC 6 months following a COPD diagnosis code during 2011-2012. Descriptive analyses included examinations of BEC stability and association with COPD exacerbations/treatments/comorbidities.

RESULTS

The most frequent COPD comorbidity was asthma (n = 1180/2909, 40.56%). Among COPD patients: 65% had BECs >150 cells/μL; 35% had BECs >300 cells/μL (non-mutually exclusive threshold categories). Treatment patterns were similar, except for more frequent inhaled corticosteroid (ICS)/long-acting beta₂-agonist use in COPD patients with asthma history (51%) than those without (31%). Factors associated with BECs >150 cells/μL in participants without ICS treatment included Māori/Pacific ethnicity, obesity, oral corticosteroid (OCS) use, and exacerbation history. When stratified by asthma history, ICS treatment, and neutrophil count above/below 5000 cells/μL, geometric mean BECs ranged from 136.70 to 398.52 cells/μL. Exploratory analyses showed a fair-good COPD/BEC measurement stability over 12 months.

CONCLUSIONS

Asthma was a common COPD comorbidity in NZ, particularly in Māori/Pacific patients. No overall relationship was observed between BEC/COPD exacerbations, which may reflect background ICS confounding. However, analyses in non-ICS treated participants suggested that Māori/Pacific patients with obesity and COPD, OCS treatment, exacerbation history, and/or elevated BECs are at the highest risk of COPD exacerbations. One BEC measurement appears a good indicator of a patient's BECs over time.

Is Blood Eosinophil Count a Biomarker for Chronic Obstructive Pulmonary Disease in a Real-World Clinical Setting? Predictive Property and Longitudinal Stability in Japanese Patients

The authors examined predictive properties and the longitudinal stability of blood eosinophil count (BEC) or three strata (<100 cells/mm³, 100-299 cells/mm³ and ≥300 cells/mm³) in patients with chronic obstructive pulmonary disease (COPD) for up to six and a half years as part of a hospital-based cohort study. Of the 135 patients enrolled, 21 (15.6%) were confirmed to have died during the follow-up period. Episodes of acute exacerbation of COPD (AECOPD) were identified in 74 out of 130 available patients (56.9%), and admission due to AECOPD in 35 out of 132 (26.5%). Univariate Cox proportional hazards analyses revealed that almost all the age, forced expiratory volume in 1 s (FEV₁) and health status measures using St. George's Respiratory Questionnaire (SGRQ) Total and COPD Assessment Test (CAT) Score were significantly related to these types of events, but the relationship between age and AECOPD did not reach statistical significance (p = 0.05). Neither BEC nor the three different groups stratified by BEC were significant predictors of any subsequent events. There were no significant differences in the BEC between Visits 1-3 (p = 0.127, Friedman test). The ICC value was 0.755 using log-transformed data, indicating excellent repeatability. In the case of assigning to strata, Fleiss' kappa was calculated to be 0.464, indicating moderate agreement. The predictive properties of BEC may be limited in a real-world Japanese clinical setting. Attention must be paid to the fact that the longitudinal stability of the three strata is regarded as moderate.

Dual Bronchodilator in the Era of Triple Therapy

Pharmacological medications used for the treatment of COPD patients have increased significantly. Long-acting bronchodilators have been recognized as the mainstay of the treatment of stable COPD, while ICS are usually added in patients with COPD who experience exacerbations, despite bronchodilator treatment. In the latest years, several studies have been published showing the beneficial effect of adding ICS on dual bronchodilation in patients suffering from more severe disease comparing triple therapy with several therapeutic regiments including dual bronchodilation and providing a message that this triple therapy might be more appropriate for COPD patients. However, not all COPD patients have a desirable response to ICS treatment while long-term ICS use in COPD is associated with several side effects. In this report, we aimed to provide a review of the current knowledge on the importance of dual bronchodilation on COPD patients and to compare its use with triple therapy, by covering a wide spectrum of topics. Finally, we propose an algorithm on performing treatment step up from dual bronchodilation to triple therapy and step down from triple to double bronchodilation considering the current evidence.

Extrafine Beclometasone Dipropionate/Formoterol Fumarate vs Double Bronchodilation Therapy in Patients with COPD: A Historical Real-World Non-Inferiority Study

Purpose

This study aimed to evaluate the non-inferiority of initiating extrafine beclometasone dipropionate/formoterol fumarate (BDP/FF) versus double bronchodilation (long-acting beta-agonists [LABA]/long-acting muscarinic antagonists [LAMA]) among patients with a history of chronic obstructive pulmonary disease (COPD) exacerbations.

Patients and Methods

A historical cohort study was conducted using data from the UK's Optimum Patient Care Research Database. Patients with COPD ≥40 years at diagnosis were included if they initiated extrafine BDP/FF or any LABA/LAMA double therapy as a step-up from no maintenance therapy or monotherapy with inhaled corticosteroids (ICS), LAMA, or LABA and a history of ≥2 moderate/severe exacerbations in the previous two years. The primary outcome was exacerbation rate from therapy initiation until a relevant therapy change or end of follow-up. Secondary outcomes included rate of acute respiratory events, acute oral corticosteroids (OCS) courses, and antibiotic prescriptions with lower respiratory indication, modified Medical Research Council score (mMRC) ≥2, and time to first pneumonia diagnosis. The non-inferiority boundary was set at a relative difference of 15% on the ratio scale. Five potential treatment effect modifiers were investigated.

Results

A total of 1735 patients initiated extrafine BDP/FF and 2450 patients initiated LABA/LAMA. The mean age was 70 years, 51% were male, 41% current smokers, and 85% had FEV₁ <80% predicted. Extrafine BDP/FF showed non-inferiority to LABA/LAMA for rate of exacerbations (incidence rate ratio [IRR] = 1.01 [95% CI 0.94-1.09]), acute respiratory events (IRR = 0.98 [0.92-1.04]), acute OCS courses (IRR = 1.01 [0.91-1.11]), and antibiotic prescriptions (IRR = 0.99 [0.90-1.09]), but not for mMRC (OR = 0.93 [0.69-1.27]) or risk of pneumonia (HR = 0.50 [0.14-1.73]). None of the a priori defined effect modifier candidates affected the comparative effectiveness.

Conclusion

This study found that stepping up to extrafine BDP/FF from no maintenance or monotherapy was not inferior to stepping up to double bronchodilation therapy in patients with a history of exacerbations.

Absolute Blood Eosinophil Counts to Guide Inhaled Corticosteroids Therapy Among Patients with COPD: Systematic Review and Meta-analysis

INTRODUCTION

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2019 recommends the use of absolute blood eosinophil count as a guide for the escalation and de-escalation of inhaled corticosteroids (ICS) in the pharmacological management of patients with chronic obstructive pulmonary disease (COPD). We evaluated the risk of moderate or severe exacerbations among patients escalating and de-escalating ICS therapy by absolute blood eosinophil thresholds in this systematic review.

METHODS

Through a comprehensive literature search of Pubmed/MEDLINE, EMBASE, and clinical trial sites up to April 2019, we identified relevant studies. We used generic inverse variance method with fixed-effects estimates to compare the risk of moderate or severe exacerbations among COPD patients with elevated blood eosinophil counts exposed to inhaled corticosteroids (ICS) versus non-ICS treatments groups expressed as risk ratios.

RESULTS

Ten studies (8 randomised control trials and 2 observational studies) were included, with a total of 85,059 COPD patients. In our pooled analysis, we found an overall reduction in risk of moderate or severe exacerbations in patients with absolute blood eosinophil thresholds ranging from ≥ 100 to ≥ 340 cells/µL among patients escalating ICS (RR, 0.77, 95% CI, 0.73-0.81). For studies evaluating the effects of de-escalation of ICS on moderate to severe exacerbations using blood eosinophil thresholds of ≥ 300 to ≥ 340 cells/µL had an increased risk of moderate or severe exacerbations following the de-escalation of ICS (RR, 1.66, 95% CI, 1.31-2.10).

CONCLUSION

This study confirms the validity of the recommended absolute blood eosinophil count thresholds for the escalation and de-escalation of ICS among COPD patients. However, this recommendation is for COPD patients with prior exacerbations rather than among newly diagnosed COPD patients as observed in this study. COPD patients with current or past history of asthma represent a unique phenotypic group which should be further evaluated.

Eosinophils in COPD-Current Concepts and Clinical Implications

In recent years, heterogeneity in chronic obstructive pulmonary disease (COPD) inflammatory patterns has been recognized as a basis for more precise treatment interventions because current therapies have limited effectiveness. Eosinophilic airway inflammation in COPD has become a subject of research interest as a potential treatment target for inhaled corticosteroid therapy. However, the role of eosinophils in COPD is still unclear, and it is unknown why only some patients with COPD develop eosinophilic airway inflammation. Induced sputum analysis is the most common method of assessing the type of airway inflammation. Accessibility to sputum induction, however, is limited in clinical practice, and blood eosinophils have been proposed to serve as a surrogate marker and treatment guide. Blood eosinophil count has been shown to poorly predict sputum eosinophilia, and, moreover, it seems to be fairly unstable and affected by various factors. Nevertheless, in several trials, blood eosinophil count appeared to predict good response to inhaled corticosteroids However, biologics targeting eosinophils do not appear to be effective in COPD. In this review, we briefly summarize the current knowledge on eosinophils in COPD pathogenesis. Then, we discuss the use of blood eosinophil count in COPD in relation to the recent Global Initiative for Chronic Obstructive Pulmonary Disease recommendations, their ability to predict sputum eosinophilia, and their potential role in guiding treatment.

The Association Between Eosinophil Variability Patterns and the Efficacy of Inhaled Corticosteroids in Stable COPD Patients

Introduction

Blood eosinophils are a predictive marker for the use of inhaled corticosteroids (ICS). However, there is concern over whether a single measure of blood eosinophils is sufficient for outlining a treatment plan. Here, we evaluated the association between variability in blood eosinophils and the effects of ICS in stable COPD cohorts.

Methods

COPD patients in the Korean COPD Subtype Study and the Seoul National University Airway Registry from 2011 to 2018 were analyzed. Based on blood eosinophils at baseline and at 1-year follow-up, the patients were classified into four groups with 250/μL as a cutoff value: consistently high (CH), consistently low (CL), variably increasing (VI), and variably decreasing (VD). We compared rates of acute exacerbations (AEs) according to ICS use in each group after calibration of severity using propensity score matching.

Results

Of 2,221 COPD patients, 618 were analyzed and a total of 125 (20%), 355 (57%), 63 (10%), and 75 (12%) patients were classified into the CH, CL, VI, and VD groups, respectively. After calibration, we found that ICS users tended to have a lower AE rate in the CH group (RR 0.41, 95% CI 0.21–0.74) and VI group (RR 0.45, 95% CI 0.22–0.88), but not in the CL group (RR 1.42, 95% CI 1.08–1.89) and VD group (RR 1.71, 95% CI 1.00–2.96).

Conclusion

More than one-fifth of patients had an inconsistent blood eosinophil level after the 1-year follow-up, and the AE-COPD rate according to ICS differed based on variability in eosinophils. Regular follow-up of blood eosinophils is required for COPD patients.

Predictive Value of Exhaled Nitric Oxide and Blood Eosinophil Count in the Assessment of Airway Eosinophilia in COPD

Purpose

Fractional exhaled nitric oxide (FENO50) level and peripheral blood eosinophil count may serve as indicators of airway eosinophilia. The aim of this study was to estimate the diagnostic value of these markers for detecting airway eosinophilia in patients with stable chronic obstructive pulmonary disease (COPD) and those experiencing an acute exacerbation (AECOPD).

Patients and Methods

FENO50 levels, sputum and blood eosinophil counts were assessed in 53 clinically stable ex-smoker COPD patients and 67 ex-smoker COPD patients experiencing a severe exacerbation. In AECOPD, clinical variables were measured at the time of hospital admission and discharge following treatment.

Results

In stable COPD, blood eosinophil count but not FENO50 level was found to be a good predictor of airway eosinophilia (area under the receiver operating characteristic curve [ROC AUC]: ≥0.82). The sensitivity and the specificity of the test ranged between 75% and 98%, the negative predictive value (NPV) was high (>90%). In AECOPD, FENO50 was predictive for airway eosinophilia (ROC AUC: >0.8) with high NPV (>88%), but with lower sensitivity and specificity (64-70%). In contrast, the predictive accuracy of blood eosinophil count for airway eosinophilia in AECOPD was modest (ROC AUC: 0.54-0.63). The combined use of the two markers provided only limited additional benefit. Correlation analyses supported ROC curve findings.

Conclusion

In stable COPD the peripheral blood eosinophil count, while in AECOPD the FENO50 level is a good surrogate marker of airway eosinophilia.

Endo-phenotyping of COPD patients

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a heterogeneous syndrome and may comprise several different phenotypes that are driven by different molecular mechanisms (endotypes). Several different clinical, genetic, and inflammatory phenotypes of COPD have been recognized and this may lead to more precise effective therapies.

AREAS COVERED

The different clinical phenotypes, including smoking versus nonsmoking COPD, small airway disease versus emphysema, non-exacerbators versus frequent exacerbators are discussed. Rare genetic endotypes (alpha₁-antitrypsin deficiency, telomerase polymorphisms), and inflammatory phenotypes (eosinophilic versus neutrophilic) are also recognized in stable and exacerbating patients and have implications for the choice of therapy.

EXPERT OPINION

Clinical phenotypes have so far not proved to be very useful in selecting more personalized therapy for COPD. Even with genetic endotypes, this has not led to improved therapy. More promising is the recognition that COPD patients who have increased sputum or blood eosinophils tend to have more frequent exacerbations and inhaled corticosteroids are more effective in preventing exacerbation. Increased blood eosinophils have proved to be a useful biomarker now used to target ICS more effectively. Furthermore, COPD patients with low eosinophils are more likely to get pneumonia with ICS and to have lower airway bacterial colonization.

The stability of blood eosinophils in stable chronic obstructive pulmonary disease: a retrospective study in Belgian primary care

Background

Blood eosinophil counts (BEC) were recently included in the 2019 Global Initiative for Obstructive Lung Disease (GOLD) guideline as an easily accessible theragnostic biomarker for Chronic Obstructive Pulmonary Disease (COPD). However, the stability of BEC remains insufficiently studied.

Methods

We conducted a retrospective study in six primary care practices in Belgium on data from Electronic Health Records of stable COPD patients, to characterise the stability of blood eosinophils over time. We report the percentage of patients with BEC persistently below or above the 2019 GOLD guideline thresholds (100 and 300 cells/μL). For each patient the mean, standard deviation (SD) and relative standard deviation (RSD) of the BEC were calculated to determine the intra-patient variability.

Results

Ninety-eight patients were included, yielding 1082 eosinophil measurements (median 8 measurements/patient), with BEC ranging between 0 and 1504 cells/μL. Four (4.1%) patients had BEC persistently below 100 cells/μL, 34 (34.7%) had measurements persistently above this threshold. Approximately half of the patients (51.0%) had BEC persistently below 300 cells/μL and 3 (3.1%) patients had counts persistently above this threshold. 28.6% of patients crossed both threshold values throughout the registration period. The mean BEC per patient ranged between 15 and 846 cells/μL with an intra-patient SD between 5 and 658 cells/μL. The mean intra-patient RSD was 0.46. There was a significant strong positive correlation (Pearson analyses) between the mean BEC and SD (r = 0.765; n = 98). Simple linear regression was used to further describe the influence of the mean eosinophil count on the SD (B = 0.500; 95%CI 0.415–0.586; n = 98; p < 0.001).

Conclusion

BEC can be variable in individual COPD patients. Therefore, the use of a single measurement to guide therapeutic decisions remains debatable. Further prospective research remains necessary to validate the reproducibility of this biomarker.

Association between COPD exacerbations and lung function decline during maintenance therapy

BACKGROUND

Little is known about the impact of exacerbations on COPD progression or whether inhaled corticosteroid (ICS) use and blood eosinophil count (BEC) affect progression. We aimed to assess this in a prospective observational study.

METHODS

The study population included patients with mild to moderate COPD, aged ≥35 years, with a smoking history, who were followed up for ≥3 years from first to last spirometry recording using two large UK electronic medical record databases: Clinical Practice Research Datalink (CPRD) and Optimum Patient Care Research Database (OPCRD). Multilevel mixed-effects linear regression models were used to determine the relationship between annual exacerbation rate following initiation of therapy (ICS vs non-ICS) and FEV₁ decline. Effect modification by blood eosinophils was studied through interaction terms.

RESULTS

Of 12178 patients included (mean age 66 years; 48% female), 8981 (74%) received ICS. In patients with BEC ≥350 cells/µL not on ICS, each exacerbation was associated with subsequent acceleration of FEV₁ decline of 19.4 mL/year (95% CI 12.0 to 26.7, p<0.0001). This excess decline was reduced by 15.1 mL/year (6.6 to 23.6) to 4.3 mL/year (1.9 to 6.7, p<0.0001) in those with BEC ≥350 cells/µL treated with ICS.

CONCLUSION

Exacerbations are associated with a more rapid loss of lung function among COPD patients with elevated blood eosinophils, defined as ≥350 cells/µL, not treated with ICS. More aggressive prevention of exacerbations using ICS in such patients may prevent excess loss of lung function.

Factors that affect blood eosinophil counts in a non-asthmatic population: Post hoc analysis of data from Brazil

Background

Improved understanding of the normal range of blood eosinophil counts (BEC) and conditions that influence them in non-asthmatic individuals should allow more accurate estimation of the threshold at which eosinophilic disease should be considered, diagnosed, and treated. This analysis investigated the impact of atopy, smoking, and parasitic infection on BEC.

Methods

This was a post hoc analysis of non-asthmatic subjects from a case-control study (CONEP 450/10) conducted at the Program for Control of Asthma in Bahia (ProAR). Participant BECs were measured at baseline; correlations between predefined risk factors and BEC were assessed via univariate and stratified analysis.

Results

Of the 454 participants included, 3% were helminth parasite-positive, 18% were non-helminth parasite-positive; and 450 had BEC data. The median (interquartile range [IQR]) BEC was 152 (96, 252) cells/μL. Any positive skin prick test, elevated total immunoglobulin E, allergic rhinitis, and being a current smoker were all individually associated with higher BEC (p < 0.05) compared with BEC in participants without these factors, but having a non-helminthic parasitic infection was not. Participants with all 4 risk factors that were associated with higher BEC had a median (IQR) BEC of 192 cells/μL (94, 416) versus 106 cells/μL (70, 164) for those with no risk factors.

Conclusions

In non-asthmatic subjects, atopy, allergic rhinitis, and current smoking status were associated with higher BEC compared with subjects without these factors, but BEC values were well below the threshold commonly accepted as normal. Therefore, BEC should be interpreted in the context of an individual's medical conditions and other BEC-influencing factors.

Blood Eosinophil Counts in Chronic Obstructive Pulmonary Disease: A Biomarker of Inhaled Corticosteroid Effects

Blood eosinophil counts have emerged as a chronic obstructive pulmonary disease (COPD) biomarker that predict the effects of inhaled corticosteroids (ICS) in clinical practice. Post-hoc and prospective analysis of randomized control trials have shown that higher blood eosinophil counts at the start of the study predict a greater response to ICS. COPD patients with frequent exacerbations (2 or more moderate exacerbations/yr) or a history of hospitalization have a greater response to ICS. Ex-smokers also appear to have a greater ICS response. Blood eosinophil counts can be combined with clinical information such as exacerbation history and smoking status to enable a precision medicine approach to the use of ICS. Higher blood eosinophil counts are associated with increased eosinophilic lung inflammation, and other biological features that may contribute to the increased ICS response observed. Emerging data indicates that lower blood eosinophil counts are associated with an increased risk of bacterial infection, suggesting complex relationships between eosinophils, ICS response, and the airway microbiome.

The stability of blood Eosinophils in chronic obstructive pulmonary disease

Blood eosinophils are a predictive biomarker of inhaled corticosteroid response in chronic obstructive pulmonary disease (COPD). We investigated blood eosinophil stability over 1 year using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2019 thresholds of < 100, 100- < 300 and ≥ 300 eosinophils/μL in 225 patients from the COPDMAP cohort. Blood eosinophils showed good stability (rho: 0.71, p < 0.001, ICC 0.84), and 69.3% of patients remained in the same eosinophil category at 1 year. 85.3% of patients with eosinophils < 100 cells/μL had stable counts. The majority of blood eosinophil counts remain stable over 1 year using the GOLD 2019 thresholds.

COPD treatment choices based on blood eosinophils: are we there yet?

Eosinophils are increasingly being recognised as an important characteristic feature of COPD. Patients with COPD and eosinophilic inflammation tend to respond to steroid therapy; however, many questions remain regarding the optimum measurement. Eosinophilic inflammation may be defined based on various sampling techniques, including eosinophil levels in blood, sputum, bronchoalveolar lavage or biopsy, which leads to inconsistencies in its definition. Blood eosinophils may increase in conjunction with sputum eosinophils during COPD exacerbations and therefore may be a good surrogate marker of airway eosinophilic inflammation. However, the timing of the blood eosinophil measurement, the stability of the eosinophil count and the threshold used in different studies are variable. The use of blood eosinophil count to direct biological therapies in COPD has also had variable outcomes. Eosinophilic inflammation has an important role in COPD management; however, its use as the optimum biomarker still needs further investigation.

Eosinophilia is common in COPD and has utility in predicting responses to inhaled or oral corticosteroids, but has limitations as a biomarkerhttp://bit.ly/2lQcMpy

Inflammatory endotypes in COPD

Chronic obstructive pulmonary disease (COPD) is a major global health problem that is poorly treated by current therapies as it has proved difficult to treat the underlying inflammation, which is largely corticosteroid-resistant in most patients. Although rare genetic endotypes of COPD have been recognized, despite the clinical heterogeneity of COPD, it has proved difficult to identify distinct inflammatory endotypes. Most patients have increased neutrophils and macrophages in sputum, reflecting the increased secretion of neutrophil and monocyte chemotactic mediators in the lungs. However, some patients also have increased eosinophils in sputum and this may be reflected by increased blood eosinophils. Increased blood and sputum eosinophils are associated with more frequent exacerbations and predict a good response to corticosteroids in reducing and treating acute exacerbations. Eosinophilic COPD may represent an overlap with asthma but the mechanism of eosinophilia is uncertain as, although an increase in sputum IL-5 has been detected, anti-IL-5 therapies are not effective in preventing exacerbations. More research is needed to link inflammatory endotypes to clinical manifestations and outcomes in COPD and in particular to predict response to precision medicines.

Blood Eosinophil Counts, Withdrawal of Inhaled Corticosteroids and Risk of COPD Exacerbations and Mortality in the Clinical Practice Research Datalink (CPRD)

Although recently introduced in the pharmacological treatment algorithm of chronic obstructive pulmonary disease (COPD), there is a need for more data supporting the use of blood eosinophil counts as a biomarker to guide inhaled corticosteroids (ICS) therapy. The aim of this study was to evaluate the risk of moderate and/or severe exacerbations and all-cause mortality in a large primary care population after withdrawal of ICS compared to continued users stratified by elevated blood eosinophil counts. In this population based cohort study, we used data from the Clinical Practice Research Datalink (CPRD) in the United Kingdom. We included subjects' aged 40 years or more who had a diagnosis of COPD. We excluded subjects with a history of asthma, pulmonary fibrosis, cardiac arrhythmia and bronchiectasis, COPD exacerbations occurring within 6 weeks prior to index date, or with a myocardial infarction within 3 months prior to index date. Continuous users were subjects who received their most recent ICS prescription within 3 months before the start of an interval. ICS withdrawals were those who discontinued ICS for more than 3 months. We evaluated the risk of moderate and/or severe exacerbations and all-cause mortality among subjects with various blood eosinophil thresholds who withdrew from ICS compared to continuous ICS users with elevated blood eosinophil levels using Cox regression analysis adjusted for potential confounders. We identified 48,157 subjects diagnosed with COPD between 1 January 2005 to 31 January 2014. Withdrawal of ICS was not associated with an increased risk of moderate-to-severe exacerbations among subjects with absolute blood eosinophil counts ≥0.34 × 10⁹ cells/L [adjusted hazard ratio (adj. HR) 0.72; 95% confidence interval (CI) 0.63-0.81] or relative counts ≥ 4.0% (adj. HR 0.72; 95% CI: 0.66-0.78). Similarly, withdrawal of ICS was not associated with an increased risk of severe exacerbations among subjects with absolute blood eosinophil ≥0.34 × 10⁹ cells/L (adj. HR 0.82; 95% CI: 0.61-1.10) or relative blood eosinophil counts ≥4.0% (adj. HR 0.80; 95% CI: 0.61-1.04). No increased risk of all-cause mortality was observed among subjects who withdrew from ICS irrespective of elevated absolute or relative blood eosinophil counts. In a real-world primary care population, we did not observe an increased risk of moderate and/or severe COPD exacerbations or all-cause mortality among subjects with eosinophilia who withdrew their use of ICS.

Inhaled corticosteroids, blood eosinophils, and FEV1 decline in patients with COPD in a large UK primary health care setting

Background: Inhaled corticosteroid (ICS)-containing medications slow rate of decline of FEV₁. Blood eosinophil (EOS) levels are associated with the degree of exacerbation reduction with ICS.

Purpose: We investigated whether FEV₁ decline differs between patients with and without ICS, stratified by blood EOS level.

Patients and methods: The UK Clinical Practice Research Datalink (primary care records) and Hospital Episode Statistics (hospital records) were used to identify COPD patients aged 35 years or older, who were current or ex-smokers with ≥2 FEV₁ measurements ≥6 months apart. Prevalent ICS use and the nearest EOS count to start of follow-up were identified. Patients were classified at baseline as higher stratum EOS (≥150 cell/µL) on ICS; higher stratum EOS not on ICS; lower stratum EOS (<150 cells/µL) on ICS; and lower stratum EOS not on ICS. In addition, an incident ICS cohort was used to investigate the rate of FEV₁ change by EOS and incident ICS use. Mixed-effects linear regression was used to compare rates of FEV₁ change in mL/year.

Results: A total of 26,675 COPD patients met our inclusion criteria (median age 69, 46% female). The median duration of follow up was 4.2 years. The rate of FEV₁ change in prevalent ICS users was slower than non-ICS users (−12.6 mL/year vs −21.1 mL/year; P =0.001). The rate of FEV₁ change was not significantly different when stratified by EOS level. The rate of FEV₁ change in incident ICS users increased (+4.2 mL/year) vs −21.2 mL/year loss in non-ICS users; P<0.001. In patients with high EOS, incident ICS patients showed an increase in FEV₁ (+12 mL/year) compared to non-ICS users whose FEV₁ decreased (−20.8 mL/year); P<0.001. No statistical difference was seen in low EOS patients. Incident ICS use is associated with an improvement in FEV₁ change, however, over time this association is lost.

Conclusion: Regardless of blood EOS level, prevalent ICS use is associated with slower rates of FEV₁ decline in COPD.

Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Lung Disease: the GOLD science committee report 2019

Precision medicine is a patient-specific approach that integrates all relevant clinical, genetic and biological information in order to optimise the therapeutic benefit relative to the possibility of side-effects for each individual. Recent clinical trials have shown that higher blood eosinophil counts are associated with a greater efficacy of inhaled corticosteroids (ICSs) in chronic obstructive pulmonary disease (COPD) patients. Blood eosinophil counts are a biomarker with potential to be used in clinical practice, to help target ICS treatment with more precision in COPD patients with a history of exacerbations despite appropriate bronchodilator treatment.The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2017 pharmacological treatment algorithms, based on the ABCD assessment, can be applied relatively easily to treatment-naive individuals at initial presentation. However, their use is more problematic during follow-up in patients who are already on maintenance treatment. There is a need for a different system to guide COPD pharmacological management during follow-up.Recent large randomised controlled trials have provided important new information concerning the therapeutic effects of ICSs and long-acting bronchodilators on exacerbations. The new evidence regarding blood eosinophils and inhaled treatments, and the need to distinguish between initial and follow-up pharmacological management, led to changes in the GOLD pharmacological treatment recommendations. This article explains the evidence and rationale for the GOLD 2019 pharmacological treatment recommendations.

The association between blood eosinophil percent and bacterial infection in acute exacerbation of chronic obstructive pulmonary disease

Introduction: The use of antibiotics is based on the clinician's experience and judgment, and antibiotics may often be overused in the treatment of acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Eosinophils have been studied as biomarkers of bacterial infection and prognostic factors in chronic obstructive pulmonary disease and AECOPD. Thus, the purpose of this study was to determine whether eosinophils could be used to determine bacterial infection in AECOPD events. Methods: We retrospectively analyzed the medical records of patients admitted to Korea University Guro Hospital for AECOPD between January 2011 and May 2017. Data pertaining to baseline characteristics, results of previous pulmonary function tests, treatment information during the admission period, and history of pulmonary treatment were collected before admission. Results: A total of 736 AECOPD events were eligible for inclusion and were divided into two groups based on the eosinophil count: those involving eosinophil counts of less than 2% (546 events) and those involving counts of 2% or more (190 events). In univariate analysis, the only bacterial pathogen identification events and bacterial-viral pathogen co-identification events were significantly more frequent in the group with eosinophil counts of less than 2% (P=0.010 and P=0.001, respectively). In logistic regression analysis, the rates of only bacterial pathogen identification [odds ratios =1.744; 95% confidence interval, 1.107-2.749; P=0.017] and bacterial-viral pathogen co-identification [odds ratios=2.075; 95% confidence interval, 1.081-3.984; P=0.028] were higher in the group with eosinophil count less than 2%. Conclusion: In conclusion, eosinophil counts of less than 2% are potential indicators of a bacterial infection in AECOPD events. Eosinophils could thus serve as a reference for the use of antibiotics in AECOPD treatment.

Stability of peripheral blood immune markers in patients with asthma

Background

Asthma is a complex disease with variable course. Efforts to identify biomarkers to predict asthma severity, the course of disease and response to treatment have not been very successful so far. We have previous suggested that PAR-2 and CRTh2 expression on specific peripheral blood cell subtypes may be biomarkers of asthma severity. We reasoned that parameters that remain stable when asthma symptoms are controlled would be the most appropriate to evaluate for their utility to predict loss of asthma control and/or severity of the disease.

Methods

Nineteen stable asthmatics were recruited from the University of Alberta Asthma clinic and followed in clinic every 3 months for a total of 4 visits. Patients had spirometry and completed the ACQ questionnaire in every visit. Blood was drawn in every visit and analyzed for a number of immune parameters by flow cytometry. These parameters included PAR-2 and CRTh2 expression on monocyte subgroups and T lymphocytes respectively, as well as numbers of eosinophils, innate lymphoid type-2 cells (ILC2) and dendritic cells. Within person stability of immune and physiological parameters was calculated using the intraclass correlation (ICC) using R version 3.4.0.

Results

FEV₁ (% predicted), FEV₁/FVC ratio, ACQ5 and ACQ7 did not differ significantly over the 4 visits, as would be expected for patients with stable asthma. Peripheral blood eosinophil numbers by Kimura stain and by flow cytometry showed ICC scores of 0.44 and 0.52 respectively, indicating moderate stability. The % of ILC2 cells in peripheral blood also showed moderate stability [ICC score of 0.45 (0.14–0.67)]. The stability for all other immune parameters was poor.

Conclusion

Among the peripheral blood immune parameters we studied, only numbers of eosinophils and ILC2 in peripheral blood were moderately stable over a year in stable asthmatics. Further studies are required to understand the reasons for the variability of the other cell types.

Clinical burden of illness among patients with severe eosinophilic COPD

Background: There are currently limited real-world data on the clinical burden of illness in patients with COPD who continue to exacerbate despite receiving triple therapy. The aim of this study was to compare the burden of COPD in patients with and without a phenotype characterized by a high blood eosinophil count and high risk of exacerbations while receiving triple therapy.

Methods: This retrospective cohort study (GSK ID: 207323/PRJ2647) used UK Clinical Practice Research Datalink records linked with Hospital Episode Statistics. Eligible patients had a COPD medical diagnosis code recorded between January 1, 2004 and December 31, 2014, and a blood eosinophil count recorded on/after that date. Patients were followed from index date (first qualifying blood eosinophil count) until December 31, 2015. The study phenotype was defined as ≥2 moderate/≥1 severe acute exacerbation of COPD (AECOPD) in the year prior to the index date, current use of multiple-inhaler triple therapy (MITT), and blood eosinophil count ≥150 cells/µL on the index date. Outcomes measured during follow-up included moderate/severe AECOPDs, severe AECOPDs, all-cause mortality, primary care (GP) clinical consultations, and non-AECOPD-related unscheduled hospitalizations.

Results: Of 46,814 patients eligible for inclusion, 2512 (5.4%) met the definition of the study phenotype. Adjusted rate ratios (95% CI) of moderate/severe AECOPDs and all-cause mortality in patients with the study phenotype versus those without were 2.32 (2.22, 2.43) and 1.26 (1.16, 1.37), respectively. For GP visits and non-AECOPD-related unscheduled hospitalizations, adjusted rate ratios (95% CI), in patients with the study phenotype versus those without, were 1.09 (1.05, 1.12) and 1.31 (1.18, 1.46), respectively.

Conclusion: Patients with COPD and raised blood eosinophil counts who continue to exacerbate despite MITT represent a distinct subgroup who experience substantial clinical burden and account for high healthcare expenditure. There is a need for more effective management and therapeutic options for these patients.

Exacerbations and health care resource use among patients with COPD in relation to blood eosinophil counts

Purpose

Current understanding of the relationship between COPD phenotype and health care resource utilization (HCRU) is limited. This real-world study evaluated disease burden and HCRU for COPD subgroups prone to exacerbation as defined by blood eosinophil (EOS) count and multiple inhaler triple therapy (MITT) use.

Methods

This was a large-scale, retrospective, longitudinal, observational cohort study using data from the US IBM Watson Explorys real-world database (GSK Study HO-17-18395). The population of interest comprised patients with COPD ≥40 years of age with ≥2 moderate or ≥1 severe exacerbations (prior year) while on inhaled maintenance therapy, with ≥1 blood EOS count. Data were analyzed during the year prior to index date (last COPD encounter between January 1, 2011 and December 31, 2016). Four subgroups were analyzed based on a combination of EOS counts (<150 and ≥150 cells/μL) and MITT use (receiving or not receiving). Among these groups, clinical characteristics, exacerbations, and HCRU were described. A sensitivity analysis that further stratified EOS into four categories (<150, ≥150–<300, ≥300–<500, and ≥500 cells/μL) was also performed.

Results

The COPD population of interest comprised 34,268 patients. Subgroups with EOS ≥150 cells/μL vs <150 cells/μL had more comorbidities and experienced significantly higher mean numbers of moderate exacerbations (not receiving MITT, ≥150 cells/μL vs <150 cells/μL: 1.93 vs 1.82, P<0.0001; receiving MITT 2.26 vs 2.16, P=0.0062) and COPD-related emergency visits (not receiving MITT, ≥150 cells/μL vs <150 cells/μL: 3.0 vs 2.5, P<0.001; receiving MITT 3.4 vs 3.1, P=0.0011). Increasing EOS category was associated with higher HCRU.

Conclusion

Blood EOS ≥150/μL cells were associated with increased HCRU and higher exacerbation rates compared with EOS <150 cells/μL, irrespective of MITT use. COPD phenotyping using blood EOS could help identify candidates for additional therapies that target eosinophilic inflammatory pathways.

Blood eosinophilia, use of inhaled corticosteroids, and risk of COPD exacerbations and mortality

PURPOSE

It remains unclear whether eosinophilia is useful for in guiding inhaled corticosteroid (ICS) therapy in chronic obstructive pulmonary disease (COPD) patients. The goal of this study is to evaluate the risk of acute exacerbations, COPD-related hospitalisations/accident and emergency visits, and all-cause mortality with various levels of eosinophil counts among COPD patients using ICS.

METHODS

A cohort study was conducted using the UK Clinical Practice Research Datalink. Patients were aged 40+ and had COPD (n = 32 693). Current users of ICS were stratified by relative and absolute eosinophil counts to determine the risk of outcomes with blood eosiniphilia using Cox regression analysis.

RESULTS

Among COPD patients, current use of ICS was not associated with a reduced risk of acute COPD exacerbations, COPD-related hospitalisations/accident and emergency visits, and all-cause mortality. Stratification of ICS use by absolute or relative eosinophil counts did not result in significant differences in risk of COPD exacerbations or hospitalisations/accident and emergency visits. However, all-cause mortality was reduced by 12% to 24% among patients with eosinophilia.

CONCLUSIONS

COPD-related acute exacerbations or hospitalisations/accident and emergency visits were not reduced with eosinophilia among users of ICS with COPD. However, all-cause mortality was reduced by 12% to 24%. These findings are potentially important and require further evaluation in prospective studies.

Relationship of Inhaled Corticosteroid Adherence to Asthma Exacerbations in Patients with Moderate-to-Severe Asthma

BACKGROUND

Patients with asthma and elevated blood eosinophils are at increased risk of severe exacerbations. Management of these patients should consider nonadherence to inhaled corticosteroid (ICS) therapy as a factor for increased exacerbation risk.

OBJECTIVE

The objective of this study was to investigate whether poor adherence to ICS therapy explains the occurrence of asthma exacerbations in patients with elevated blood eosinophil levels.

METHODS

This historical cohort study identified patients within the Optimum Patient Care Research Database, aged 18 years or more, at Global Initiative for Asthma step 3 or 4, with 2 or more ICS prescriptions during the year before the clinical review. Patient characteristics and adherence (based on prescription refills and patient self-report) for ICS therapy were analyzed for those with elevated (>400 cells/μL) or normal (≤400 cells/μL) blood eosinophils.

RESULTS

We studied 7195 patients (66% female, mean age 60 years) with median eosinophil count of 200 cells/μL and found 81% to be not fully adherent to ICS therapy. A total of 1031 patients (14%) had elevated blood eosinophil counts (58% female, mean age 60 years), 83% of whom were not fully adherent to ICS. An increased proportion of adherent patients in the elevated blood eosinophil group had 2 or more exacerbations (14.0% vs 7.2%; P = .003) and uncontrolled asthma (73% vs 60.8%; P = .004) as compared with non-fully adherent patients.

CONCLUSIONS

Approximately 1 in 7 patients had elevated eosinophils. Adherence to ICS therapy was not associated with decreased exacerbations for these patients. Additional therapy should be considered for these patients, such as biologics, which have been previously shown to improve control in severe uncontrolled eosinophilic asthma.

Demographic and Clinical Characteristics of COPD Patients at Different Blood Eosinophil Levels in the UK Clinical Practice Research Datalink

Blood eosinophil count may be a useful biomarker for predicting response to inhaled corticosteroids and exacerbation risk in chronic obstructive pulmonary disease (COPD) patients. The optimal cut point for categorizing blood eosinophil counts in these contexts remains unclear. We aimed to determine the distribution of blood eosinophil count in COPD patients and matched non-COPD controls, and to describe demographic and clinical characteristics at different cut points. We identified COPD patients within the UK Clinical Practice Research Database aged ≥40 years with a FEV₁/FVC <0.7, and ≥1 blood eosinophil count recorded during stable disease between January 1, 2010 and December 31, 2012. COPD patients were matched on age, sex, and smoking status to non-COPD controls. Using all blood eosinophil counts recorded during a 12-month period, COPD patients were categorized as "always above," "fluctuating above and below," and "never above" cut points of 100, 150, and 300 cells/μL. The geometric mean blood eosinophil count was statistically significantly higher in COPD patients versus matched controls (196.6 cells/µL vs. 182.1 cells/µL; mean difference 8%, 95% CI: 6.8, 9.2), and in COPD patients with versus without a history of asthma (205.0 cells/µL vs. 192.2 cells/µL; mean difference 6.7%, 95%, CI: 4.9, 8.5). About half of COPD patients had all blood eosinophil counts above 150 cells/μL; this persistent higher eosinophil phenotype was associated with being male, higher body mass index, and history of asthma. In conclusion, COPD patients demonstrated higher blood eosinophil count than non-COPD controls, although there was substantial overlap in the distributions. COPD patients with a history of asthma had significantly higher blood eosinophil count versus those without.