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

Area of Science:

• Pulmonology
• Respiratory Medicine
• Asthma Research

Background:

• Small airways dysfunction (SAD) is an under-recognized, treatable aspect of asthma.
• Spirometry measures SAD using FEF25-75, but it's effort and volume dependent.
• Forced oscillometry is an effort-independent, more sensitive method for SAD assessment.

Purpose of the Study:

• To determine the incidence of abnormal SAD values in severe, uncontrolled asthma patients before biologic therapy.
• To compare the sensitivity of spirometry versus oscillometry in detecting SAD in this population.

Main Methods:

• Retrospective review of severe uncontrolled asthma patients.
• Assessment of SAD using spirometry (FEF25-75) and forced oscillometry.
• Analysis of SAD incidence and comparison between methods.

Main Results:

• SAD was identified in 63% of patients.
• In patients with preserved spirometry, 29% showed impaired oscillometry compared to only 6% with impaired FEF25-75.
• Oscillometry detected SAD more frequently than spirometry in this cohort.

Conclusions:

• SAD is prevalent in severe uncontrolled asthma.
• Forced oscillometry is a more sensitive tool than spirometry for detecting SAD, particularly in patients with seemingly normal spirometry.
• These findings suggest oscillometry could improve SAD diagnosis in asthma management.