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

Abstract

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 [

Prevalence of eosinophilic, atopic, and overlap phenotypes among patients with severe asthma in Saudi Arabia: a cross-sectional study

“…Peripheral blood eosinophil counts as high as 400 cells/mm 3 have been linked to increased asthma exacerbations; however, patients with adult-onset asthma who have blood eosinophil counts ≥ 300 cells/mm 3 present with a distinct phenotype of severe asthma that includes frequent exacerbations and a poor prognosis [ 16 ]. Blood eosinophil counts ≥ 200 cells/mm 3 have been associated with asthma exacerbation, including asthma-related outpatient visits and emergency department visits [ 17 ]. Studies of anti-eosinophilic therapies indicate that patients with blood eosinophil counts ≥ 300 cells/mm 3 can benefit from targeted treatment [ 18 – 20 ].…”

Selected hematological abnormalities and their associated factors among asthmatic patients in Northwest Ethiopia: a cross-sectional study

“…Moreover, eosinophilia is considered a prognostic marker and can be associated with frequent asthma exacerbations [ 21 , 60 ]. High eosinophil counts in the blood can be linked to an increase odds of asthma exacerbation [ 23 ]. Recent studies reported that patients with a blood eosinophil count greater than 400 cells/μl experienced severe asthma exacerbation, acute respiratory conditions, and a risk for airflow obstruction among asthma patients [ 54 , 61 ].…”

“…Eosinophilia can be related to the severity of the disease [ 20 , 21 ]. It is known to be an independent risk factor for asthma exacerbations, emergency department visits, and hospitalization due to asthma [ 22 , 23 ]. In addition, eosinophilia is related to an increased risk of moderate and severe asthma exacerbations [ 23 , 24 ].…”

“…It is known to be an independent risk factor for asthma exacerbations, emergency department visits, and hospitalization due to asthma [ 22 , 23 ]. In addition, eosinophilia is related to an increased risk of moderate and severe asthma exacerbations [ 23 , 24 ]. Eosinophils release lipid mediators and toxic basic proteins that mediate airflow obstruction, bronchial epithelium injury, airway inflammation, and mucous hypersecretion [ 25 , 26 ].…”

Selective IgA Deficiency a Probable Risk of Recurrent Chest Infections in Asthmatics

“…Secondly, regarding the fact that serum IgE level increases in asthmatic patients, the results of several studies as well as the current one have corroborated it. [14][15][16][17][20][21][22] Davila et al conducted a multicenter, retrospective, observational study including 383 patients with allergic asthma adult patients. They aimed to evaluate the association between serum total IgE levels and disease severity in adult patients with persistent allergic asthma and to explore the main predictors of IgE levels.…”