Clinical impact of obesity on oscillometry lung mechanics in adults with asthma

Background: In the year 2035, projections have estimated that 5% of the Scottish population will be morbidly obese defined as a body mass index (BMI) greater than or equal to 40 kg/m2. Airway oscillometry is an effortindependent test akin to bronchial sonar which measures resistance and compliance. Objective: To evaluate the impact of obesity on lung mechanics using oscillometry. Methods: Clinical data for 188 patients with respiratory physician-diagnosed moderate-to-severe asthma were retrospectively collected and analyzed. Results: Obesity (BMI 30-39.9 kg/m2) and morbid obesity (BMI >= 40 kg/m2) were associated with a significantly worse heterogeneity of peripheral resistance between 5 Hz and 20 Hz and peripheral compliance as low-frequency reactance at 5 Hz and area under the reactance curve, as compared with normal weight (BMI 18.5-24.9 kg/m2). Cluster analysis incorporating oscillometry identified a patient cohort who was older, obese, and female with combined impairment of spirometry and oscillometry coupled with more frequent severe exacerbations. Conclusion: Obesity is associated with worse peripheral airway dysfunction in moderate-to-severe asthma, including a patient cluster who was older, obese, and female with more frequent exacerbations. (c) 2023 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)