Investigations of a combination of atopic status and age of asthma onset identify asthma subphenotypes.

OBJECTIVE: Subphenotypes of asthma may be determined by age onset and atopic status. We sought to characterize early or late onset atopic asthma with fungal or non-fungal sensitization (AAFS or AANFS) and non-atopic asthma (NAA) in children and adults in the Severe Asthma Research Program (SARP). SARP is an ongoing project involving well-phenotyped patients with mild to severe asthma. METHODS: Phenotypic comparisons were performed using Kruskal-Wallis or chi-square test. Genetic association analyses were performed using logistic or linear regression. RESULTS: Airway hyper-responsiveness, total serum IgE levels, and T2 biomarkers showed an increasing trend from NAA to AANFS and then to AAFS. Children and adults with early onset asthma had greater % of AAFS than adults with late onset asthma (46% and 40% vs. 32%; P < 0.00001). In children, AAFS and AANFS had lower % predicted FEV1 (86% and 91% vs. 97%) and greater % of patients with severe asthma than NAA (61% and 59% vs. 43%). In adults with early or late onset asthma, NAA had greater % of patients with severe asthma than AANFS and AAFS (61% vs. 40% and 37% or 56% vs. 44% and 49%). The G allele of rs2872507 in GSDMB had higher frequency in AAFS than AANFS and NAA (0.63 vs. 0.55 and 0.55), and associated with earlier age onset and asthma severity. CONCLUSIONS: Early or late onset AAFS, AANFS, and NAA have shared and distinct phenotypic characteristics in children and adults. AAFS is a complex disorder involving genetic susceptibility and environmental factors.

Atopy Is Associated with Age at Asthma Onset in Elderly Patients.

BACKGROUND: Asthma in the elderly population (60 years of age and older) is frequently underdiagnosed, as well as atopy. Atopy, although more prevalent in younger patients, can be a major cause of asthma in the elderly. Chronic obstructive pulmonary disease (COPD) and cardiovascular disease are common differential diagnoses, especially in elderly smokers. OBJECTIVE: The objective of this study was to assess atopy and comorbidities in elderly patients with asthma. METHODS: This was an observational and retrospective study involving elderly asthmatic patients followed up at a tertiary center. Patients were assessed for severity of asthma, frequency of atopy, and frequency of comorbidities concomitant with asthma. Then, they were classified according to their age at asthma onset and the groups compared with each other for atopy, spirometric parameters, and comorbidities. RESULTS: This study included 243 elderly asthmatic patients, 71.8% of them presenting severe disease and 82.3% forced expiratory volume in 1 second (FEV1) < 80%. Gastroesophageal reflux disease, obesity, and asthma-COPD overlap syndrome were observed, respectively, in 64%, 37%, and 13% of these patients. Atopy was observed in 63%, mainly in those with early onset disease, and its frequency decreased as the age of asthma onset increased (P < .05). Total serum IgE was higher for allergic patients and FEV1 values were lower for patients with long-term asthma. Aspirin-exacerbated respiratory disease was more frequent in patients with nonallergic asthma. CONCLUSIONS: Most elderly asthmatic patients followed up in our tertiary center were atopic and higher values of total serum IgE suggest atopy. Atopy was inversely correlated with age of asthma onset. The diagnosis of allergic asthma in the elderly population is essential to treat patients more properly, improving their quality of life and decreasing asthma morbidity and mortality.