Clinical Characterization and Predictors of IOS-Defined Small-Airway Dysfunction in Asthma

Marcello Cottini; Anita Licini; Carlo Lombardi; Alvise Berti

doi:10.1016/j.jaip.2019.10.040

Clinical Characterization and Predictors of IOS-Defined Small-Airway Dysfunction in Asthma

J Allergy Clin Immunol Pract. 2020 Mar;8(3):997-1004.e2. doi: 10.1016/j.jaip.2019.10.040. Epub 2019 Nov 11.

Authors

Marcello Cottini¹, Anita Licini², Carlo Lombardi³, Alvise Berti⁴

Affiliations

¹ Allergy and Pneumology Outpatient Clinic, Bergamo, Italy. Electronic address: cottinimarcello@gmail.com.
² Allergy and Pneumology Outpatient Clinic, Bergamo, Italy.
³ Departmental Unit of Allergology, Immunology & Pulmonary Diseases, Fondazione Poliambulanza, Brescia, Italy.
⁴ Ospedale Santa Chiara and Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy; Thoracic Disease Research Unit, Mayo Clinic, Rochester, Minn. Electronic address: alvise.berti@apss.tn.it.

PMID: 31726234
DOI: 10.1016/j.jaip.2019.10.040

Abstract

Background: The involvement of small airways has recently gained greater recognition in asthma. Impulse oscillometry (IOS) is a simple and noninvasive method based on the forced oscillation technique, for the detection of small-airway dysfunction (SAD).

Objective: To identify the predictors of SAD in an unselected sample of 400 patients with physician-diagnosed asthma.

Methods: All patients underwent standard spirometry and IOS at the first visit, and were stratified by the presence of SAD defined by IOS (fall in resistance from 5 to 20 Hz [R5-R20] > 0.07 kPa × s × L^-1). Univariable and multivariable analyses and classification tree method were used to analyze cross-sectional relationships between clinical variables and outcome (SAD).

Results: SAD was present in 62% of the cohort. Subjects with SAD showed a less well-controlled asthma, according to the Global Initiative for Asthma definition, and a higher mean inhaled corticosteroid dosage use compared with subjects without SAD (both P < .001). Increased fractional exhaled nitric oxide (odds ratio [OR], 2.05; 95% CI, 1.14-3.70), female sex (OR, 2.27; 95% CI, 1.29-4.06), smoking (OR, 3.06; 95% CI, 1.60-6.05), older age (OR, 3.08; 95% CI, 1.77-5.49), asthma-related night awakenings (OR, 3.34; 95% CI, 1.85-6.17), overweight (OR, 3.64; 95% CI, 1.99-6.85), and exercise-induced asthma symptoms (OR, 6.39; 95% CI 3.65-11.45) were independent predictors of SAD. Classification tree analysis confirmed that exercise-induced asthma, overweight, asthma-related night awakenings, smoking, and older age have potential for clinical use in distinguishing patients with SAD from those without it.

Conclusions: We identified predictors of SAD and showed that especially exercise-induced asthma, overweight, asthma-related night awakenings, smoking, and older age were strongly associated with SAD.

Keywords: Asthma; Atopy; Community-treated asthma; Overweight; Risk factors; Skin test; Small airway dysfunction; Small airways.

MeSH terms

Aged
Asthma* / diagnosis
Asthma* / epidemiology
Cross-Sectional Studies
Female
Humans
Oscillometry
Respiratory Function Tests
Respiratory System
Spirometry