Eosinophilic asthma, according to a blood eosinophil criterion, is associated with disease severity and lack of control among underprivileged urban Brazilians

Abstract

Background: Asthma is a syndrome with multiple phenotypes. Peripheral blood eosinophil counts might be the ideal biomarker to identify subjects with eosinophilic asthma. It is available, inexpensive, and it is associated with eosinophilia in sputum. Objective: The aim of this study was to evaluate whether blood eosinophilia is associated with asthma severity and to evaluate whether blood eosinophilia is associated with lack of control of asthma symptoms and airway obstruction. Methods: Case control study. The cases were subjects recruited from a cohort of patients with severe asthma, in Salvador-BR, demanding continuous inhaled corticosteroids and LABA. There were two control groups: 1) subjects with mild/moderate asthma, 2) subjects with no asthma. Subjects enrolled in the study answered questionnaires, had their blood and stool samples collected, performed spirometry and SPT. We established a cutoff ≥ 260 cells/mm3 for blood eosinophilia. Results: We evaluated 544 subjects in the case group, 452 subjects with mild to moderate asthma and 450 subjects with no asthma. The subjects of the case group had higher odds of presenting the eosinophilic phenotype in comparison to subjects with mild to moderate asthma [OR 1.60 95CI(1.19-2.16)] and no asthma [OR 3.93; 95CI(2.90-5.33)]. The eosinophilic phenotype, according to blood count, is associated with uncontrolled asthma [OR 1.56; 95CI(1.06-2.28)], but it is not associated with airway obstruction [OR 0.87; 95CI(0.61-1.24)]. Conclusion: We conclude that the blood eosinophilia is a biomarker associated with asthma severity and poor symptom control, but we found no association with reduced lung function.

Asthma similarities across ProAR (Brazil) and U-BIOPRED (Europe) adult cohorts of contrasting locations, ethnicity and socioeconomic status

“…Subjects with MMA were non-smokers for at least 12 months, with less than 5 pack-year smoking history and controlled or partially controlled asthma symptoms, as defined by GINA, whilst receiving a dose of <500 μg fluticasone propionate/day or equivalent [6]. The sample of Brazilian subjects from ProAR included 544 adults from a cohort with previously-untreated SA (upon enrolment in the cohort) together with 452 adults, invited from the same communities by public advertisement and classified as having MMA by a doctor's interview at the time of the present study [14]. The classification of MMA was based on current concepts of severity, including subjects with intermittent symptoms and no regular treatment or low dose of controller medications, upon evaluation by a specialist.…”

Toxoplasma gondii protects from IgE sensitization and induces Th1/Th2 immune profile

“…Blood was collected for antibody detection, to perform whole‐blood culture (both described below in detail) and skin prick testing (SPT), as described by Lima‐Matos and collaborators …”

Severe asthma and eligibility for biologics in a Brazilian cohort

“…This is an analysis of the database of the ProAR Cohort (17), which comprises 544 adult patients (!18 years old) with SA according to previous definitions of the Education Prevention Program -Practical guide for the diagnosis and management of asthma/ NHLBI-NIH (1997) (18), and that were included in a case-control study conducted from 2013-2015 (19). Patients with chronic conditions such as COPD, structural changes of the lungs and pregnancy were excluded.…”

“…Patients with chronic conditions such as COPD, structural changes of the lungs and pregnancy were excluded. Details and results of the case-control study have been published previously (19).…”