Marcello Cottini1, Anita Licini2, Carlo Lombardi3, Alvise Berti4. 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. Santa Chiara Hospital and Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Trento, Italy and Thoracic Disease Research Unit, Mayo Clinic, Rochester, USA. Electronic address: alvise.berti@apss.tn.it.
Abstract
BACKGROUND: Impulse oscillometry (IOS) is a noninvasive method based on the forced oscillation technique able to detect small airway dysfunction (SAD) in asthma. We aimed to analyze the prevalence and the functional features of IOS-defined SAD across the different Global Initiative for Asthma (GINA) steps. METHODS: A cross-sectional, single-center study in which 400 consecutive adult patients with physician-diagnosed, community-managed asthma underwent standard spirometry and IOS, and were stratified by stepwise GINA classification. SAD was defined by IOS as a fall in resistance from 5 to 20 Hz [R5-R20]>0.07kPa × s × L-1. RESULTS: The prevalence of IOS-defined SAD ranged between 58.3% (GINA step 2) and 78.6% (GINA step 5), without statistically significant difference within GINA steps (p > 0.05 in all comparisons). Isolated SAD (i.e. without proximal airways involvement) was similarly represented across GINA steps 2-4. Peripheral airways resistance (R5-R20) tended to a progressive increase with the worsening of GINA steps, and was significantly higher in steps 4-5 compared to the other steps (p < 0.05). The proportion of patients with FEF25-75%-defined SAD (<60%) was lower than the IOS-defined one in GINA steps 2-4 (p < 0.05). Only non-significant or weak inverse correlations between R5-R20 and FEF25-75% were observed within each GINA step, with the exception of GINA step 5, which showed a strong, inverse correlation (r = -0.80, p = 0.0005). CONCLUSIONS: This study shows that first, IOS-defined SAD is overwhelmingly present across asthma severities; second, airways resistance increases with the worsening of GINA steps; and third, SAD may be overlooked by standard spirometry, especially in milder asthma.
BACKGROUND: Impulse oscillometry (IOS) is a noninvasive method based on the forced oscillation technique able to detect small airway dysfunction (SAD) in asthma. We aimed to analyze the prevalence and the functional features of IOS-defined SAD across the different Global Initiative for Asthma (GINA) steps. METHODS: A cross-sectional, single-center study in which 400 consecutive adult patients with physician-diagnosed, community-managed asthma underwent standard spirometry and IOS, and were stratified by stepwise GINA classification. SAD was defined by IOS as a fall in resistance from 5 to 20 Hz [R5-R20]>0.07kPa × s × L-1. RESULTS: The prevalence of IOS-defined SAD ranged between 58.3% (GINA step 2) and 78.6% (GINA step 5), without statistically significant difference within GINA steps (p > 0.05 in all comparisons). Isolated SAD (i.e. without proximal airways involvement) was similarly represented across GINA steps 2-4. Peripheral airways resistance (R5-R20) tended to a progressive increase with the worsening of GINA steps, and was significantly higher in steps 4-5 compared to the other steps (p < 0.05). The proportion of patients with FEF25-75%-defined SAD (<60%) was lower than the IOS-defined one in GINA steps 2-4 (p < 0.05). Only non-significant or weak inverse correlations between R5-R20 and FEF25-75% were observed within each GINA step, with the exception of GINA step 5, which showed a strong, inverse correlation (r = -0.80, p = 0.0005). CONCLUSIONS: This study shows that first, IOS-defined SAD is overwhelmingly present across asthma severities; second, airways resistance increases with the worsening of GINA steps; and third, SAD may be overlooked by standard spirometry, especially in milder asthma.
Authors: Marcello Cottini; Carlo Lombardi; Giovanni Passalacqua; Diego Bagnasco; Alvise Berti; Pasquale Comberiati; Gianluca Imeri; Massimo Landi; Enrico Heffler Journal: Front Med (Lausanne) Date: 2022-05-23