Small Airway Dysfunction Links Asthma Severity with Physical Activity and Symptom Control

Area of Science:

• Pulmonary Medicine
• Respiratory Research
• Asthma Pathophysiology

Background:

• Small airway dysfunction (SAD) is poorly understood in relation to asthma control and physical activity (PA).
• Investigating SAD's role is crucial for understanding asthma management and patient quality of life.

Purpose of the Study:

• To investigate the interrelations among small airway dysfunction (SAD), risk factors for asthma severity, asthma control, and physical activity (PA).

Main Methods:

• Assessed SAD using impulse oscillometry and inert gas washout in adults with mild-to-moderate and severe asthma, and healthy controls.
• Evaluated SAD prevalence and its association with asthma severity risk factors, type 2 inflammation, systemic inflammation, asthma control (AC), and PA.
• Employed structural equation modeling to integrate causal pathways among clinical variables.

Main Results:

• SAD prevalence was high, ranging from 53-64% in mild-to-moderate asthma and 75-90% in severe asthma.
• Severe SAD correlated with poor asthma control (AC) and reduced physical activity (PA).
• Age, obesity, systemic inflammation, T2 inflammation, and smoking independently predicted SAD. SAD was the primary determinant of AC, which influenced PA. Obesity impacted AC directly and indirectly.

Conclusions:

• Small airway dysfunction (SAD) is a prevalent feature in asthma, connecting distal lung function abnormalities with asthma severity risk factors, control, and physical activity.
• SAD significantly impacts asthma control and physical activity, highlighting its importance in disease management.
• Understanding these interrelations can inform targeted interventions for improved asthma outcomes.