Role of body anthropometry in severe asthmatic patients: Evidences from the Severe Asthma Network in Italy (SANI) registry

Asthma and obesity are both chronic diseases. Obesity is a common comorbidity and a risk factor of severe asthma, associated with increased asthma exacerbation risk, poorer asthma control and reduced quality of life. However, the responsible mechanisms are poorly understood. The aim of this study was to detect parameters associated with obesity in patients with severe asthma in order to check different pattern of inflammation in obese asthmatics. Baseline data from the Severe Asthma Network in Italy (SANI) registry were analysed in 1922 patients with severe asthma. Demographic, clinical and functional features were compared, according to body mass index (BMI). The prevalence of overweight and obesity among severe asthma patients was 34,8 and 20,3, respectively. Females were more prevalent in the obese cluster (p < 0.001). Asthma onset age in overweight and obese patients was higher than in normal population (p < 0.001). Obese subjects reported less frequently chronic rhinosinusitis with nasal polyposis (CRSwNP) and more frequently impaired sleep quality, cardiovascular disease, and type-2 diabetes (p < 0.001). Severe asthma patients with obesity had lower predicted FVC values (89.0 ± 19.2 vs 93.5 ± 20.2; p 0.002) and higher FEV1/FVC ratio (69.9 ± 11.5 vs 66.9 ± 12.4; p < 0.001) than patients without obesity. Obese asthmatics had lower blood eosinophilic count, and fractional exhaled nitric oxide (FeNO) levels than non-obese asthmatics. Asthma control test (ACT) was significantly poorer in obese patients (17, IQR 12–21) than other subgroups. Regarding treatment, overweight and obese patients were more likely to receive a GINA-Step 5 therapy (p 0.023), with more than 20 of obese asthmatics having frequent exacerbations requiring oral corticosteroid (OCS). Patients with severe asthma and obesity presented different characteristics that support the existence of distinct asthma phenotype in obese patients. Trial registration: Trial registry: ClinicalTrials.gov. ID: NCT06625216. Retrospectively registered October 3, 2024.