Oscillometry defined small airways dysfunction in patients with severe uncontrolled asthma and preserved spirometry

TY - JOUR

T1 - Oscillometry defined small airways dysfunction in patients with severe uncontrolled asthma and preserved spirometry

AU - Greig, Robert

AU - Suter, Philipp

AU - Chan, Rory

AU - Lipworth, Brian

N1 - Copyright: © 2026 The Authors. Published by Elsevier Ltd.

PY - 2026/3/24

Y1 - 2026/3/24

N2 - Small airways dysfunction (SAD) is an important treatable trait in asthma that is often under-recognised. It can be assessed through spirometry as forced expiratory flow between 25% and 75% of vital capacity however this is limited due to being both effort and volume dependent. Forced oscillometry technique is effort independent and showing to be more sensitive for SAD. We reviewed patients with severe uncontrolled asthma prior to commencing biologic therapy to identify the incidence of abnormal SAD defining values. SAD was identified in 63% of patients. Of the 31 patients with preserved spirometry (normal FEV1 and FEV1/FVC), only 6% had an impaired FEF25-75 while 29% had impaired oscillometry. This result highlights SAD is a common finding in severe uncontrolled asthma and that oscillometry is more sensitive to identifying than spirometry at identifying SAD, particularly when spirometry is preserved.

AB - Small airways dysfunction (SAD) is an important treatable trait in asthma that is often under-recognised. It can be assessed through spirometry as forced expiratory flow between 25% and 75% of vital capacity however this is limited due to being both effort and volume dependent. Forced oscillometry technique is effort independent and showing to be more sensitive for SAD. We reviewed patients with severe uncontrolled asthma prior to commencing biologic therapy to identify the incidence of abnormal SAD defining values. SAD was identified in 63% of patients. Of the 31 patients with preserved spirometry (normal FEV1 and FEV1/FVC), only 6% had an impaired FEF25-75 while 29% had impaired oscillometry. This result highlights SAD is a common finding in severe uncontrolled asthma and that oscillometry is more sensitive to identifying than spirometry at identifying SAD, particularly when spirometry is preserved.

KW - Asthma

KW - oscillometry derived ratios

KW - spirometry

KW - tezepelumab

U2 - 10.1016/j.rmed.2026.108790

DO - 10.1016/j.rmed.2026.108790

M3 - Comment/debate

SN - 0954-6111

JO - Respiratory Medicine

JF - Respiratory Medicine

M1 - 108790

ER -