Burden of asthma with elevated blood eosinophil levels

PRevalence of the Eosinophilic Phenotype Among SeveRE asthma patients in Lebanon: results of the PREPARE study

BACKGROUND

The prevalence of eosinophilic asthma in Lebanon, one of the most severe phenotypes among severe asthma, is not known. This study aimed at determining the prevalence of the eosinophilic phenotype defined as an eosinophil count ≥ 300 cells/mm3 among severe asthma patients in Lebanon.

METHODS

The Lebanese Chapter of the PREPARE study was a national, multicenter, cross-sectional observational study. Patients aged ≥ 12 years with severe asthma were identified and prospectively enrolled during clinic visits and completed the Global Initiative for Asthma (GINA) assessment of asthma control questionnaire. Patients' health characteristics were collected from medical records and blood samples were obtained for measurement of serum IgE levels and blood eosinophils count.

RESULTS

Overall, 101 patients (with mean age of 46.3 ± 17.0 years and 73.27% females) with severe asthma were included and, among them, 37% had eosinophilic phenotype, 67.3% had atopic phenotype with IgE > 100 IU/mL and 25.7% patients had overlapping atopic and eosinophilic phenotypes. Close to 80% had late-onset asthma, beyond 12 years of age, and around 85% had at least one severe exacerbation in the 12 months prior to study enrolment. The majority of participants [64.4%] had uncontrolled asthma, 24.7% had partially controlled symptoms and 10.9% had controlled symptoms. 19.8% of participants were on chronic oral corticosteroids, 78.2% had short course treatment of corticosteroids and all were prescribed a combination of inhaled corticosteroids and long-acting beta-agonist.

CONCLUSIONS

The majority of patients with severe asthma were uncontrolled of which 37% present with an eosinophilic phenotype, which should be taken into consideration for better management of these patients in view of the novel phenotype-specific therapeutic options.

The Unified Airway Hypothesis: Evidence From Specific Intervention With Anti-IL-5 Biologic Therapy

The unified airway hypothesis proposes that upper and lower airway diseases reflect a single pathological process manifesting in different locations within the airway. Functional, epidemiological, and pathological evidence has supported this well-established hypothesis for some time. However, literature on the pathobiologic roles/therapeutic targeting of eosinophils and IL-5 in upper and lower airway diseases (including asthma, chronic rhinosinusitis with nasal polyps [CRSwNP], and nonsteroidal anti-inflammatory drug-exacerbated respiratory disease) has recently emerged. This narrative review revisits the unified airway hypothesis by searching the scientific literature for recent learnings and clinical trial/real-world data that provide a novel perspective on its relevance for clinicians. According to the available literature, eosinophils and IL-5 have important pathophysiological roles in both the upper and lower airways, although the impact of eosinophils and IL-5 may vary in asthma and CRSwNP. Some differential effects of anti-IL-5 and anti-IL-5-receptor therapies in CRSwNP have been observed, requiring further investigation. However, pharmaceutical targeting of eosinophils and IL-5 in patients with upper, lower, and comorbid upper and lower airway inflammation has led to clinical benefit, supporting the hypothesis that these are linked conditions manifesting in different locations. Consideration of this approach may improve patient care and aid clinical decision making.

Toward a better understanding of severe asthma phenotypes in Latin America: results from the PREPARE study

OBJECTIVE

Data on severe asthma phenotypes in Latin America are lacking. The PREPARE study describes the prevalence of certain determinants of severe asthma among patients in 5 Latin American countries with blood eosinophil counts (BEC) ≥300 cells/mm³ and serum immunoglobulin E (IgE) concentrations >100 IU/mL.

METHODS

In this cross-sectional study, information on demographics, disease characteristics, and asthma treatments were extracted from the existing medical records of patients aged ≥12 years attending centers specialized in severe asthma management. Medical record data were transcribed onto electronic case report forms. Blood eosinophil counts and IgE concentrations were assayed from specimens obtained at study visit. Data were analyzed with descriptive statistics.

RESULTS

Data from 461 patients with severe asthma (mean age, 50.5 years) were analyzed. Most patients were female (73%), had a body mass index of ≥25 kg/m² (77%), and received full healthcare reimbursement (63%). In the previous 12 months, 52% of patients experienced ≥1 severe exacerbation and 44% received oral corticosteroid burst therapy. Blood eosinophil counts ≥300 cells/mm³ and ≥150 cells/mm³ were reported in 44% and 76% of patients, respectively. In 58% of patients, serum IgE concentrations exceeded 100 IU/mL. Uncontrolled asthma was documented in 50% (n = 230) of patients.

CONCLUSIONS

The PREPARE study provides useful insights about the prevalence of eosinophilic and atopic phenotypes in patients with severe asthma in Latin America, thereby paving the way for a more personalized approach to managing severe asthma. Notwithstanding the treatment at specialized medical centers, disease burden remained high in this study population.

Association between Exposure to Selected Heavy Metals and Blood Eosinophil Counts in Asthmatic Adults: Results from NHANES 2011-2018

(1) Background: Heavy metals are widely used and dispersed in the environment and people's daily routines. Many studies have reported an association between heavy metal exposure and asthma. Blood eosinophils play a crucial role in the occurrence, progression, and treatment of asthma. However, there have thus far been few studies that aimed to explore the effects of heavy metal exposure on blood eosinophil counts in adults with asthma. Our study aims to discuss the association between metal exposure and blood eosinophil counts among asthmatic adults. (2) Methods: A total of 2026 asthmatic individuals were involved in our research from NHANES with metal exposure, blood eosinophils, and other covariates among the American population. A regression model, the XGBoost algorithm, and a generalized linear model (GAM) were used to explore the potential correlation. Furthermore, we conducted a stratified analysis to determine high-risk populations. (3) Results: The multivariate regression analysis indicated that concentrations of blood Pb (log per 1 mg/L; coefficient β, 25.39; p = 0.010) were positively associated with blood eosinophil counts. However, the associations between blood cadmium, mercury, selenium, manganese, and blood eosinophil counts were not statistically significant. We used stratified analysis to determine the high-risk group regarding Pb exposure. Pb was identified as the most vital variable influencing blood eosinophils through the XGBoost algorithm. We also used GAM to observe the linear relationship between the blood Pb concentrations and blood eosinophil counts. (4) Conclusions: The study demonstrated that blood Pb was positively correlated with blood eosinophil counts among asthmatic adults. We suggested that long-time Pb exposure as a risk factor might be correlated with the immune system disorder of asthmatic adults and affect the development, exacerbation, and treatment of asthma.

Comparison between clinical trials and real-world evidence studies on biologics for severe asthma

In recent years, the more widespread availability of biological drugs with specific mechanisms of action has led to significant breakthroughs in the management of severe asthma. Over time, numerous randomised clinical trials have been conducted to evaluate the efficacy and safety of these biologics and define the eligibility criteria of patients suitable for various therapeutic options. These studies were conducted under controlled conditions not always applicable to real life. For this and other reasons, real-world evidence and pragmatic studies are required to provide useful information on the effectiveness of biological drugs and their safety, even in the long term. Because differences in outcomes have sometimes emerged between clinical trials and real-life studies, it is important to clarify the causes of these discrepancies and define the significance of the results of studies conducted in the course of daily clinical practice. Thus, a scientific debate is ongoing, and no consensus has been reached. The purpose of this narrative review is to analyse the differences between randomised trials and real-world evidence studies, focusing on their roles in guiding clinicians among different therapeutic options and understanding the reasons for the large discrepancies often found in the results obtained.

Eosinophil-derived neurotoxin: An asthma exacerbation biomarker in children

Background: Asthma is a heterogeneous disease, characterized by chronic airway inflammation. Asthma exacerbations (AE) are episodes characterized by a progressive increase in symptoms of shortness of breath, cough, wheezing, or chest tightness with a decrease in lung function. There have been previous studies that examined the role of eosinophil-derived neurotoxin (EDN) in asthma, but there have been no studies of the role of EDN in children experiencing AE. Objective: In this study, we aimed to examine the association of EDN with lung function and prognosis in children admitted for severe AE. Methods: We enrolled 82 children who were admitted for severe AE at two different university hospitals in South Korea between January 2018 and December 2019. Blood tests, including white blood cell count, myeloperoxidase (MPO), total eosinophil count, EDN, C-reactive protein (CRP) level, and interleukin (IL) 4, IL-5, IL-10 values, and lung function were measured on admission and at discharge in each patient. Results: We observed significant decreases in the levels of MPO, EDN, CRP, and IL-4, with significant improvement in lung function after treatment. We then classified the subjects into two groups of different clinical phenotypes: eosinophilic asthma exacerbation (EAE) group and non-EAE group. EDN levels were higher and lung functions were lower in the EAE group. Also, we found that the EDN level was a significant biomarker useful for predicting the number of days for hospital stay. Conclusion: We found that EDN can act as a biomarker that reflects lung function, and that EDN could act as a prognostic biomarker, which demonstrated the complex role of EDN in children experiencing AE.

Blood eosinophil count as predictor of asthma exacerbation. A meta-analysis

BACKGROUND

Evidence about the association of high blood eosinophil count with asthma exacerbation is inconsistent and unclear. The objective of this meta-analysis was to determine whether elevated blood eosinophil count predicts asthma exacerbation.

METHODS

We searched MEDLINE, EMBASE, and additional databases, without any language restriction. We also checked the reference lists of the included studies and of relevant systematic reviews. The main outcome was the occurrence of asthma exacerbation. We calculated global pooled odds ratios (ORs) and their 95% confidence intervals (CIs) and performed predefined subgroup analyses. We appraised the quality of the studies using Newcastle-Ottawa Scale, examined the heterogeneity between studies, assessed publication bias, and carried out sensitivity analyses.

RESULTS

Among 1567 retrieved publications, 23 observational studies comprising 155,772 participants met the inclusion criteria. High blood eosinophil count was associated with higher odds of asthma exacerbation [OR: 1.31 (95% CI: 1.16, 1.49)], specifically with asthma-related outpatient visits [OR: 1.46 (95% CI: 1.25, 1.70)] and emergency department visits [OR: 1.63 (95% CI: 1.29, 2.07)]. A significant association was observed starting from an eosinophils' cutoff value of 200 cells/μl. The association was observed for cohort studies [OR: 1.30 (95%CI: 1.13, 1.49)], North American studies [OR: 1.43 (95%CI: 1.31, 1.57)], Asian populations [OR: 1.67 (95%CI: 1.34, 2.08)], children [OR: 1.38 (95%CI: 1.22, 1.56)], and studies that adjusted for inhaled corticosteroids therapy [OR: 1.42 (95%CI: 1.28, 1.56)].

CONCLUSIONS

Blood eosinophil counts ≥ 200 cells/µL are associated with asthma exacerbation. Blood eosinophil count is a modifiable factor that could be addressed in asthma management strategies.

Can eosinophilia and neutrophil-lymphocyte ratio predict hospitalization in asthma exacerbation?

OBJECTIVE

Asthma is one of the most common diseases amongst children. Blood eosinophil count and neutrophil-lymphocyte ratio (NLR) are known as markers for phenotyping asthma. This study was performed to investigate blood eosinophil count and NLR as predictors of hospitalization in pediatric asthma exacerbations.

DATA SOURCES AND STUDY SELECTIONS

In this cross-sectional study, children admitted to hospital ward for more severe asthma exacerbation were compared with non-hospitalized children with moderate to severe asthma exacerbation whose asthma exacerbation was managed in emergency department or outpatient clinic. We investigated patients' characteristic and factors associated with hospitalization.

RESULTS

A total of 211 children with moderate to severe asthma exacerbation (mean age [Formula: see text] years old) were enrolled in the study including 91 hospitalized patients and 120 non-hospitalized patients. For the prediction of hospitalization, an ROC Curve analysis was performed and revealed a cut-off of 298 cells/µL and 2.52 of blood eosinophil count and NLR, respectively. In multivariate analysis, not using an asthma action plan (OR 2.22, 95% CI 1.09-4.49; P = 0.027), a blood eosinophil count [Formula: see text] 298 (OR 8.79, 95% CI 4.44-17.4; P < 0.001) and an NLR [Formula: see text] 2.52 (OR 2.13, 95% CI 1.09-4.14; P = 0.027) were associated with hospitalization.

CONCLUSION

Blood eosinophil count and NLR were found to be higher in hospitalized children with more severe asthma exacerbation compared to non-hospitalized patients. These markers can be indicators for asthma exacerbation severity.

Disease burden of eosinophilic airway disease: Comparing severe asthma, COPD and asthma-COPD overlap

BACKGROUND AND OBJECTIVE

There is less understanding of phenotypes and disease burden in asthma-COPD overlap (ACO) than either disease alone. Blood eosinophils may help identify the patients in the clinic with eosinophilic airway inflammation. The potential value of this approach requires an understanding of the illness burden associated with eosinophilic ACO, eosinophilic severe asthma and eosinophilic COPD, defined by blood eosinophils.

METHODS

Participants from studies of multidimensional assessment in airway disease were pooled to identify patients with ACO (n = 106), severe asthma (n = 64) and COPD alone (n = 153). Patients were assessed cross-sectionally for demographic and clinical characteristics, including disease burden indicators such as health-related quality of life (HRQoL) and past-year exacerbation. Eosinophilic patients were identified using different thresholds of blood eosinophil count.

RESULTS

Using a blood eosinophil count ≥0.3 × 10⁹ /L, 41% had eosinophilic airway disease: 55% in ACO, 44% in severe asthma and 29% in COPD. Blood and sputum eosinophils were moderately correlated (r_s = 0.51, n = 257, P < 0.001). Burden of disease was similar between eosinophilic and non-eosinophilic airway diseases, with poor HRQoL and high number of past-year exacerbations. Burden of disease was similar across eosinophilic severe asthma, COPD and ACO. Eosinophilic COPD tended to have poorer health status than eosinophilic ACO and severe asthma; however, in context of a high prevalence of eosinophilic ACO, cumulative population-level burden of eosinophilic disease was greater in ACO.

CONCLUSION

Disease burden across eosinophilic ACO, eosinophilic severe asthma and eosinophilic COPD was high, particularly cumulative population-level burden in ACO. Factors beyond airway inflammation may drive disease burden in severe patients.

Diagnosis of Asthma Based on Routine Blood Biomarkers Using Machine Learning

Intelligent medical diagnosis has become common in the era of big data, although this technique has been applied to asthma only in limited contexts. Using routine blood biomarkers to identify asthma patients would make clinical diagnosis easier to implement and would enhance research of key asthma variables through data mining techniques. We used routine blood data from healthy individuals to construct a Mahalanobis space (MS). Then, we calculated Mahalanobis distances of the training routine blood data from 355 asthma patients and 1,480 healthy individuals to ensure the efficiency of MS. Orthogonal arrays and signal-to-noise ratios were used to optimize blood biomarker variables. Receiver operating characteristic (ROC) curve was used to determine the threshold value. Ultimately, we validated the system on 182 individuals based on the threshold value. Out of 35 patients with asthma, MTS correctly classified 94.15% of patients. In addition, 97.20% of 147 healthy individuals were correctly classified. The system isolated 7 routine blood biomarkers. Among these biomarkers, platelet distribution width, mean platelet volume, white blood cell count, eosinophil count, and lymphocyte ratio performed well in asthma diagnosis. In brief, MTS shows promise as an accurate method to identify asthma patients based on 7 vital blood biomarker variables and threshold determined by the ROC curve, thus offering the potential to simplify diagnostic complexity and optimize clinical efficiency.

Effect of clinically significant thresholds of eosinophil elevation on health care resource use in asthma

BACKGROUND

Blood eosinophil counts correlate with exacerbations, but there is a lack of consensus on a clinically relevant definition of eosinophil count elevation.

OBJECTIVE

To analyze health care resource use among patients with elevated blood eosinophil counts defined at 150 cells/μL or greater and 300 cells/μL or greater.

METHODS

Data on patients who received a diagnosis of asthma between 2007 and 2016 were extracted from EMRClaims + database. Patients were defined as having elevated eosinophil counts if any test result during 3 months before follow-up found blood eosinophil count of 150 cells/μL or more or 300 cells/μL or more. Hospitalizations, emergency department visits, outpatient visits, and associated costs were compared. With logistic regression, likelihood of hospitalization was assessed in the presence of eosinophil elevation.

RESULTS

Among 3687 patients who met the study criteria, 1152 received a test within 3 months before the follow-up period, of whom 644 (56%) had elevated eosinophil counts of 150 cells/μL or greater and 322 (29%) had eosinophil counts of 300 cells/μL or greater. Overall, the mean (SD) number of hospitalizations for patients with elevated eosinophil counts vs the comparator was significantly greater (0.29 [0.92] vs 0.17 [0.57], P < .001 at ≥150 cells/μL and 0.30 [0.95] vs 0.18 [0.61] at ≥300 cells/μL, P = .001). The total mean cost was significantly greater for patients with elevated eosinophil counts (at ≥150 cells/μL: $10,262 vs $7149, P < .001 and at ≥300 cells/μL: $9966 vs $7468, P = .003).

CONCLUSION

Patients with asthma incurred greater health care resource use when their blood eosinophil counts were elevated at 150 cells/μL or greater and 300 cells/μL or greater as measured within 3 months of follow-up.

Mechanisms and Management of Asthma Exacerbations

Acute asthma remains an important medical emergency, the most frequent cause of acute admissions in children and a major source of morbidity for adults with asthma. In all ages with asthma, the presence of exacerbations is an important defining characteristic of asthma severity. In this review, we assess the epidemiology of acute asthma, the triggers of acute exacerbations, and the mechanisms that underlie these exacerbations. We also assess current treatments that prevent exacerbations, with an emphasis on the role of type 2 airway inflammation in the context of acute exacerbations and the novel treatments that effectively target this. Finally we review current management strategies of the exacerbations themselves.

Establishment of reference intervals for complete blood count parameters in venous blood for children in the Xiamen area, China

OBJECTIVES

To observe changes in the complete blood count (CBC) venous blood parameters of healthy children and establish appropriate reference intervals (RIs).

METHODS

Overall, 4066 healthy children were selected and divided into four groups: infants, toddlers, preschool-age children and school-age children. Venous blood was analysed for 17 parameters. Outlier data for each parameter were eliminated and RIs were established based on the Clinical and Laboratory Standards Institute C28-A3c guideline.

RESULTS

The RIs for certain parameters differed among the different age groups. The white blood cell (WBC) count differed among the four age groups. The variation trends for absolute neutrophil count in all age groups were opposite to those for WBC and absolute lymphocyte count. The mean absolute eosinophil count values were significantly higher in the infant group than in the other groups. The RIs for red blood cell were identical across all age groups except in infants. The mean Hb level for infants was significantly lower than that for the other age groups. The mean and RI for platelet count were significantly higher in the infant group than in the other groups.

CONCLUSIONS

There are dynamic variations in the values reported for measurements of most CBC parameters in children. Hence, such results should always be interpreted according to the child's age. Thus establishing appropriate RIs for different age groups in paediatrics is essential.

Prevalence of Asthma and COPD and Blood Eosinophil Count in a Middle-Aged Belgian Population

Various phenotypes exist in asthma and Chronic Obstructive Pulmonary Disease (COPD). These are important to identify in order to guide treatment decisions. We aim to investigate the prevalence and clinical characteristics of obstructive airway diseases in the middle-aged population. We estimated the prevalence of COPD and/or asthma in the Asklepios cohort study (Belgium), using information from the third European Community Respiratory Health Survey (ECRHS3), medical records, and spirometry. Respiratory symptoms, respiratory medication, and current disease status distinguished clinical from sub-clinical cases. In addition, we compared the blood eosinophil count/µL (median [IQR]) between cases and controls. Of the 2221 participants (mean age 56.1 ± 5.9 years; 48.7% males), 138 (6.2%) participants had clinical current asthma, 22 (1.0%) participants had sub-clinical ever asthma, 102 (4.6%) had sub-clinical spirometry-defined COPD, 104 (4.6%) participants had clinical spirometry-confirmed COPD, and 11 (0.5%) had asthma and COPD overlap (ACO). Clinical current asthma (160.0 [110.0–250.0]), sub-clinical ever asthma (170.0 [110.0–230.0]), and clinical COPD (160.0 [110.0–220.0])—but less sub-clinical COPD (140.0 [90.0–210.0])—had higher eosinophil counts, compared to controls (130.0 [80.0–200.0]). We conclude that obstructive airway diseases are prevalent in the middle-aged Asklepios cohort. Moreover, the systemic eosinophil count is increased in clinical COPD cases, and in asthma cases regardless of clinical remission.

Exploring the Utility of Noninvasive Type 2 Inflammatory Markers for Prediction of Severe Asthma Exacerbations in Children and Adolescents

BACKGROUND

Noninvasive markers of type 2 inflammation are needed to identify children and adolescents who might benefit from personalized biologic therapy.

OBJECTIVE

We hypothesized that blood eosinophil counts would predict 1 or more acute visits for asthma and that prediction could be improved with the addition of a second, noninvasive type 2 inflammatory biomarker.

METHODS

Children and adolescents 5 to 21 years (N = 589) with an asthma exacerbation necessitating systemic corticosteroid treatment in the previous year completed a characterization visit and telephone calls at 6 and 12 months. The primary outcome was an acute visit for asthma with receipt of systemic corticosteroids. Acute visits were verified by medical record review. Exploratory outcomes included time to first acute visit and hospitalization.

RESULTS

Acute visits occurred in 106 (35.5%) children and 72 (24.8%) adolescents. Elevated blood eosinophils were associated with increased odds and shorter time to first acute visit, but optimal cut-points differed by age (≥150 vs ≥300 cells/μL for children vs adolescents, respectively). The addition of a second marker of type 2 inflammation did not improve prediction in children, but increased the odds and hazard of an acute visit up to 16.2% and 11.9%, respectively, in adolescents. Similar trends were noted for hospitalizations.

CONCLUSIONS

Blood eosinophils and other noninvasive markers of type 2 inflammation may be useful in the clinical assessment of children and adolescents with asthma. However, features of type 2 inflammation vary by age. Whether children and adolescents also respond differently to management of type 2 inflammation is unclear and warrants further evaluation.

The prevalence and disease burden of severe eosinophilic asthma in Japan

Background: There are limited data on the prevalence and burden of severe eosinophilic asthma (SEA) both in Japan and globally. This study aimed to assess the prevalence and burden of SEA in Japan. Methods: This study was a retrospective, observational cohort analysis using health records or health insurance claims from patients with severe asthma treated at Kyoto University Hospital. The primary outcome was the prevalence of SEA, defined as a baseline blood eosinophil count ≥300 cells/μL. Secondary outcomes included frequency and risk factors of asthma exacerbations, and asthma-related healthcare resource utilization and costs. Results: Overall, 217 patients with severe asthma were included; 160 (74%) had eosinophil assessments. Of these, 97cases (61%), 54cases (34%), and 33cases (21%) had a blood eosinophil count ≥150, ≥300, and ≥500 cells/μL, respectively. Proportion of SEA was 34%. Blood eosinophil count was not associated with a significantly increased frequency of exacerbations. In the eosinophilic group, lower % forced expiratory volume in 1 second and higher fractional exhaled nitric oxide were predictive risk factors, while the existence of exacerbation history was a predictive risk factor for asthma exacerbations in the non-eosinophilic group. Severe asthma management cost was estimated as ¥357,958/patient-year, and asthma exacerbations as ¥26,124/patient-year. Conclusions: Approximately, one-third of patients with severe asthma in Japan have SEA. While risk factors for exacerbations differed between SEA and severe non-eosinophilic asthma, both subgroups were associated with substantial disease and economic burden. From subgroup analysis, blood eosinophil counts could be an important consideration in severe asthma management.

The characterization of asthma with blood eosinophilia in adults in Latin America

Objective: To identify and characterize asthma with blood eosinophilia in adults. Methods: This cross-sectional study consisted of 164 asthma patients, aged 18 years or older. Multivariate analyses by logistic regression were performed to identify clinical characteristics and biomarkers associated with asthma with blood eosinophilia (defined as asthma and a peripheral blood eosinophil count ≥400 cells/mm³). To evaluate the diagnostic accuracy of these biomarkers, the sensitivity, specificity and predictive values were calculated. Additionally, the area under the receiver operating characteristic (ROC) curve (AUC) was estimated for each biomarker. Results: Overall, 37.8% (95%CI: 30.7-45.4%) of asthma patients had blood eosinophilia. The following factors were associated with this characteristic: patient age <50 years (OR 3.25; 95% CI: 1.33-7.94), a serum level of IgE ≥300 UI/mL (OR 2.32; 95%CI: 1.14-4.75), and an Asthma Control Test (ACT) score <20 points (OR 3.10; 95%CI: 1.35-4.75); asthma with blood eosinophilia was also associated with a baseline FEV₁/FVC <70% (OR 2.68; 95%CI: 1.28-5.59). On the other hand, age <50 years and ACT score <20 showed the highest sensitivity (above 80% each). Serum IgE level ≥300 UI/mL had the highest specificity (almost 68%). Finally, those with an ACT score <20 had the highest AUC (68%). Conclusions: In our study population, one-third of asthmatic adults had asthma with blood eosinophilia. Furthermore, the prevalence was greater in those ≤50 years of age; these patients experienced more severe, more poorly controlled asthma and had higher total serum IgE levels.

Effects of systemic corticosteroids on blood eosinophil counts in asthma: real-world data

Introduction: Systemic corticosteroids (SCS) are effective anti-inflammatory therapies for patients with severe or persistent asthma. Use of SCS reduces blood eosinophil counts; the magnitude and duration of reduction in real-world settings needs further investigation. Objective: To examine the SCS effect on blood eosinophil counts over time among patients with asthma in a real-world setting. Methods: This retrospective study used Reliant Medical Group (Worcester, MA) electronic medical records between January 2011 and December 2015. Patients aged ≥12 years with ≥1 SCS prescription (first: index date), ≥1 asthma diagnosis, and ≥1 eosinophil count in each 12-month pre- and post-index periods were included for the study. Endpoints included SCS treatment patterns, time to SCS discontinuation, and changes in index blood eosinophil counts (≥150, ≥300, and ≥400 cells/µL) with SCS initiation and discontinuation. Results: At index visit, 642 of 1198 included patients had a blood eosinophil count ≥150 cells/µL. After an average initial SCS prescription of 35 mg/day, mean (% change) eosinophil counts at month 1 in the ≥150, ≥300, and≥400 cells/µL subgroups decreased from index by 112 (-30%), 202 (-34%), and 290 (-36%) cells/µL, respectively. Of the patients with an eosinophil count ≥150 cells/µL at index, who discontinued SCS within 7, 14, or 21 days after the index date, 21%, 26%, and 25% had an eosinophil count <150 cells/µL 1-month post-index, respectively. Conclusion: Blood eosinophil counts decreased following initiation of SCS therapy and had not returned to index levels several weeks after SCS discontinuation. The time frame of SCS discontinuation is an important consideration when identifying patients with eosinophilic asthma.

Association between blood eosinophil count and risk of readmission for patients with asthma: Historical cohort study

Background

Recent studies have demonstrated an association between high blood eosinophil counts and greater risk of asthma exacerbations. We sought to determine whether patients hospitalized for an asthma exacerbation were at greater risk of readmission if they had a high blood eosinophil count documented before the first hospitalization.

Methods

This historical cohort study drew on 2 years of medical record data (Clinical Practice Research Datalink with Hospital Episode Statistics linkage) of patients (aged ≥5 years) admitted to hospital in England for asthma, with recorded blood eosinophil count within 1 baseline year before admission. We analyzed the association between high blood eosinophil count (≥0.35x10⁹ cells/L) and readmission risk during 1 year of follow-up after hospital discharge, with adjustment for predefined, relevant confounders using forward selection.

Results

We identified 2,613 eligible patients with asthma-related admission, of median age 51 years (interquartile range, 36–69) and 76% women (1,997/2,613). Overall, 835/2,613 (32.0%) had a preadmission high blood eosinophil count. During the follow-up year, 130/2,613 patients (5.0%) were readmitted for asthma, including 55/835 (6.6%) with vs. 75/1,778 (4.2%) without high blood eosinophil count at baseline (adjusted hazard ratio [HR] 1.49; 95% CI 1.04–2.13, p = 0.029). The association was strongest in never-smokers (n = 1,296; HR 2.16, 95% CI 1.27–3.68, p = 0.005) and absent in current smokers (n = 547; HR 1.00, 95% CI 0.49–2.04, p = 0.997).

Conclusions

A high blood eosinophil count in the year before an asthma-related hospitalization is associated with increased risk of readmission within the following year. These findings suggest that patients with asthma and preadmission high blood eosinophil count require careful follow-up, with treatment optimization, after discharge.

Prevalence of Patients Eligible for Anti-IL-5 Treatment in a Cohort of Adult-Onset Asthma

BACKGROUND

Antibodies against the IL-5 pathway have been developed for the treatment of late-onset eosinophilic corticosteroid-resistant asthma. However, the prevalence of severe asthma and the proportion of patients who could benefit from such treatment among the general population of asthmatics remain unknown.

OBJECTIVE

To evaluate the prevalence and characteristics of patients eligible to anti-IL-5 treatment and severe asthma in an unselected cohort of adult-onset asthma.

METHODS

Seinäjoki Adult Asthma Study is a 12-year follow-up study of patients with new-onset adult asthma (n = 203). Prevalence was estimated based on information collected at 12-year follow-up visit. Health care use was collected from the whole 12-year follow-up period.

RESULTS

The prevalence of anti-IL-5-treatable patients was 2%, when the following criteria were used: daily use of medium-to-high inhaled corticosteroid (ICS) dose and long-acting β₂-agonist, ≥2 exacerbations/previous year and blood eosinophil count ≥300 cells/μL or fraction of exhaled nitric oxide ≥ 50 ppb. The prevalence of severe asthma, as defined according to European Respiratory Society/American Thoracic Society, was 5.9%, and only 1 patient met criteria for both groups. When compared with anti-IL-5 eligible patients, severe asthmatics were more often current smokers at diagnosis, obese, used higher ICS dose, and had higher blood neutrophils 12 years after diagnosis. Both groups differed from nonsevere asthma by a higher number of all and unplanned respiratory-related visits to health care. Severe asthmatics showed the highest number of hospitalizations.

CONCLUSIONS

In a cohort of unselected consecutive patients with adult-onset asthma, 5.9% fulfilled criteria for severe asthma and 2% qualified for anti-IL-5 treatment. Both groups represent a high burden to health care and specifically targeted treatment could lead to lower use of health care at long term.

Health care resource utilization and characteristics of patients with eosinophilic asthma in secondary health care in Finland

Background: Eosinophilic airway inflammation is common in asthma patients and appears to be associated with severe exacerbations and loss of asthma control. Objective: To describe the resource utilization and clinical characteristics of patients with eosinophilic asthma. Design: Asthma patients ≥18 years with ≥1 blood eosinophil count in secondary care (South West Finland) during 2003‒2013 were included. Clinical characteristics (age, lung function, body mass index, and comorbidities) and asthma-related resource utilization (hospital admissions, outpatient visits, and emergency room [ER] visits) were retrieved. Resource utilization rates were compared for patients with blood eosinophil ≤ or >300 cells/μL, using adjusted negative binomial regression models. Results: Overall, 4,357 eligible patients were identified (mean age 60 years, females 68%), of which 1,927 (44%) had >300 eosinophil cells/μL blood. Patients with ≤300 and >300 eosinophil counts, exhibited similar clinical characteristics, including advanced age, poor lung function, and overweight. Comorbidities such as pneumonia, sinusitis, and nasal polyps, were more frequent among those with >300 eosinophil cells/μL blood compared with patients with lower counts. Eosinophil counts >300 cells/μL were associated with greater hospital admissions (rate ratio [RR] [95% confidence interval CI]: 1.13 [1.02;1.24]) and outpatient visits (RR [95% CI]: 1.11 [1.03;1.20]) compared with patients with lower eosinophil counts. Rates of ER visits were similar between the patient groups (RR [95% CI]: 0.99 [0.87;1.12]). Conclusions: Hospital admissions and outpatient visits occurred more often for patients with eosinophil counts >300 cells/µL, than for patients with lower eosinophil counts. Routine blood eosinophil screening might be useful to identify patients with an eosinophilic phenotype eligible for more targeted treatments.

Low-density lipoprotein receptor-related protein 1 attenuates house dust mite-induced eosinophilic airway inflammation by suppressing dendritic cell-mediated adaptive immune responses

BACKGROUND

Low-density lipoprotein receptor-related protein 1 (LRP-1) is a scavenger receptor that regulates adaptive immunity and inflammation. LRP-1 is not known to modulate the pathogenesis of allergic asthma.

OBJECTIVE

We sought to assess whether LRP-1 expression by dendritic cells (DCs) modulates adaptive immune responses in patients with house dust mite (HDM)-induced airways disease.

METHODS

LRP-1 expression on peripheral blood DCs was quantified by using flow cytometry. The role of LRP-1 in modulating HDM-induced airways disease was assessed in mice with deletion of LRP-1 in CD11c⁺ cells (Lrp1^fl/fl; CD11c-Cre) and by adoptive transfer of HDM-pulsed CD11b⁺ DCs from Lrp1^fl/fl; CD11c-Cre mice to wild-type (WT) mice.

RESULTS

Human peripheral blood myeloid DC subsets from patients with eosinophilic asthma have lower LRP-1 expression than cells from healthy nonasthmatic subjects. Similarly, LRP-1 expression by CD11b⁺ lung DCs was significantly reduced in HDM-challenged WT mice. HDM-challenged Lrp1^fl/fl; CD11c-Cre mice have a phenotype of increased eosinophilic airway inflammation, allergic sensitization, T_H2 cytokine production, and mucous cell metaplasia. The adoptive transfer of HDM-pulsed LRP-1-deficient CD11b⁺ DCs into WT mice generated a similar phenotype of enhanced eosinophilic inflammation and allergic sensitization. Furthermore, CD11b⁺ DCs in the lungs of Lrp1^fl/fl; CD11c-Cre mice have an increased ability to take up HDM antigen, whereas bone marrow-derived DCs display enhanced antigen presentation capabilities.

CONCLUSION

This identifies a novel role for LRP-1 as a negative regulator of DC-mediated adaptive immune responses in the setting of HDM-induced eosinophilic airway inflammation. Furthermore, the reduced LRP-1 expression by circulating myeloid DCs in patients with eosinophilic asthma suggests a possible role for LRP-1 in modulating type 2-high asthma.

Point-of-care blood eosinophil count in a severe asthma clinic setting

BACKGROUND

One of the main severe asthma phenotypes is severe eosinophilic or eosinophilic refractory asthma for which novel biologic agents are emerging as therapeutic options. In this context, blood eosinophil counts are one of the most reliable biomarkers.

OBJECTIVE

To evaluate the performance of a point-of-care peripheral blood counter in a patients with severe asthma.

METHODS

The blood eosinophil counts of 76 patients with severe asthma were evaluated by point-of-care and standard analyzers.

RESULTS

A significant correlation between blood eosinophils assessed by the 2 devices was found (R² = 0.854, P < .001); similar correlations were found also for white blood cells, neutrophils, and lymphocytes. The point-of-care device had the ability to predict blood eosinophil cutoffs used to select patients for biologic treatments for severe eosinophilic asthma and the ELEN index, a composite score useful to predict sputum eosinophilia.

CONCLUSION

The results of our study contribute to the validation of a point-of-care device to assess blood eosinophils and open the possibility of using this device for the management of severe asthma management.