Impact of Blood Eosinophil Variability in Asthma: A Real-Life Population Study

Abstract

Rationale: Blood eosinophil count predicts response to inhaled corticosteroids and specific biologic therapies in selected asthma patients. Despite this important role, fundamental aspects of eosinophil behavior in asthma have not been studied. ObjectivesTo investigate the behavior of blood eosinophils in a population comparing their distribution with the general population and studying their intra-individual variability over time in relation to hospital episodes (emergency department visits and hospitalizations) in clinical practice. Methods: The distribution and variability of 35,703 eosinophil determinations in 10,059 stable asthma patients were investigated in the Majorca Real-Life Investigation in COPD and Asthma cohort (MAJORICA). Eosinophil distribution in the asthma population was compared with a control sample from the general population of 8,557 individuals.Eosinophil variability and hospital episodes were analyzed using correlations, ROC curves and multiple regression analysis. We defined the Eosinophil Variability Index (EVI) as (Eos max -Eos min /Eos max ) x 100%. The findings of the asthma population were retested in an external well-characterized asthma cohort. Results:The eosinophil count values and variability were higher in the asthma population than in the general population (p-value<0.001). Variability data showed a better association with hospital episodes than the counting values. An EVI≥50% was a better predictor for any hospital episode than any of the absolute counting values. These results were validated in the external cohort. Conclusion:The eosinophil variability in asthma patients better identifies the risk of any hospital episode than the absolute counting values currently used to target specific treatments.

Eosinophilic Patterns in Patients with Seasonal Allergy Affected by Bronchial Asthma and Rhinitis/Rhinosinusitis: Efficacy of Benralizumab in Patients with the Persistent Pattern

“…In addition, most of our patients would have been underestimated and/or overestimated with a single determination of AEC performed during a nadir or a peak in these cells, respectively (Figure 2B). Indeed, in recent studies performed in real-life settings on large cohorts of individuals, seasonal allergy was only one of several intrinsic and extrinsic factors causing intraindividual and interindividual variability in AEC in the general population as well as in the asthma population [11,24,25]. Therefore, it is conceivable that the MAEC assessment through four AEC determinations could be a more appropriate tool for managing patients with various eosinophilic conditions [11].…”

“…However, this threshold is debated because an AEC of ≥150 cells/µL includes individuals with AEC in the normal range (300 to 500 cells/µL, [10]). In addition, recent studies performed on large cohorts indicated that the threshold of AEC identifying eosinophilic individuals is higher than ≥ 150 cells/µL in the general population (≥ 210 cells/µL [24] and ≥ 280 cells/µL [25]) and asthma patients (≥ 384 cells/µL [25]). Finally, it is unclear whether a single AEC can be used as a reliable marker for eosinophilic asthma [11,26].…”

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

“…The reason why high eosinophil is less likely the possibility of asthma and COPD compared with ACO, may be that the exacerbation frequency of ACO is higher than that of asthma or COPD alone ( 3 , 31 ). A large number of studies have shown that eosinophil is closely related to the exacerbation of COPD and asthma ( 32 – 34 ). Compared with patients without eosinophilia, those with eosinophilia (≥300 cells/μl) had a higher frequency of readmission for acute exacerbation of COPD (AECOPD) during the 1-year follow-up period.…”

Association Between Clinical Burden and Blood Eosinophil Counts in Asthma: Findings From a Korean Adult Asthma Cohort

“…Jung et al 25 reported that a single eosinophil count may not suffice when managing eosinophilic asthma; several factors (including technical considerations) may influence the count. Toledo-Pons et al 26 reported that, compared with the absolute count, eosinophil variability was a better indicator of hospital episode risk. Because eosinophil stability may be problematic, other biomarkers that accurately reflect eosinophilic inflammatory status are needed.…”