Variability of blood eosinophils in patients in a clinic for severe asthma

Abstract

Background: Blood eosinophils are used to determine eligibility for agents targeting IL-5 in patients with uncontrolled asthma. However, little is known about the variability of blood eosinophil measures in these patients before treatment initiation.Objective: To characterize variability and patterns of variability of blood eosinophil levels in a real-world clinic for severe asthmatics.Methods: Retrospective review of blood eosinophils measured over a 5-year period in patients enrolled in an urban clinic. Repeated measures of blood eosinophil levels in individuals were evaluated, and cluster analysis was performed to characterize patients by eosinophil patterns. Clinical characteristics associated with eosinophil levels and patterns of variability were analysed. Results:Patients treated in the Bellevue Hospital Asthma Clinic within a 3-month period were identified (n = 219). Blood eosinophil measures were obtained over the previous 5 years. Only 6% (n = 13) of patients had levels that were consistently above 300 cells/μL. Nearly 50% (n = 104) had eosinophil levels that traversed the threshold of 300 cells/μL. In contrast, 102 (46%) had levels that never reached the threshold of 300 cells/μL. Cluster analyses revealed three clusters with differing patterns of levels and variability. There was a suggestion of decreased clinical control and increased atopy in the cluster with the greatest variability in blood eosinophil measures. Conclusion:In an urban clinic for patients referred for uncontrolled asthma, blood measures of eosinophils were variable and showed differing patterns of variability.These data reinforce the need to perform repeated eosinophil blood measures for appropriate designation for therapeutic intervention.

Clinical evaluation of type 2 disease status in a real‐world population of difficult to manage asthma using historic electronic healthcare records of blood eosinophil counts

“…8,9 Moreover, they offer theragnostic value by defining a phenotype of severe asthma patients that can be stratified towards newly emerged anti-IL5/ IL-5 receptor alpha (IL-5 Rα) therapies. [10][11][12][13] Eosinophilic inflammation is recognized to fluctuate in both blood and sputum over time [14][15][16][17] : few patients are 'eosinophilic' at every measurement. 18,19 This therefore challenges the robustness of translating associations determined by single-measurement crosssectional study designs, 20 into clinical practice, particularly when full blood counts are among the most commonly requested blood test panels in clinical care.…”

Characterization of Persistent Uncontrolled Asthma Symptoms in Community Members Exposed to World Trade Center Dust and Fumes

“…We used blood biomarkers and FeNO to assess the inflammatory status of the patients. We, and others, have shown that blood biomarkers, including those for eosinophils, may be variable [ 76 ] and FeNO varies over time and control status.…”

Developments allergy in 2019 through the eyes of Clinical and Experimental Allergy, Part II clinical allergy

“…However, little is known about the longitudinal variation in blood eosinophils in patients and their utility as a biomarker from a pragmatic real‐world clinic. Rakowski and colleagues have addressed this very important issue by reviewing variability in blood eosinophils measured over a 5‐year period 52 . Only 13/219 patients had a blood eosinophil count consistently above 300 cells/mcl.…”