Tracking severe asthma improvement with biologic therapy using spirometry and impulse oscillometry: a real-world...

Severe asthma patients receiving biologic therapy require accurate functional assessment and longitudinal monitoring. Spirometry and impulse oscillometry (IOS) may provide complementary information on lung function. The aim of this study was to compare spirometry and IOS in severe asthma patients treated with biologics, evaluating their concordance and clinical relevance, and to assess longitudinal changes in asthma control, oral corticosteroid (OCS) use, exacerbations, and healthcare utilization over 18 months.

In this real-world dual-centre longitudinal study, 40 patients with severe asthma treated with biologic therapy underwent spirometry and IOS at baseline and after 6, 12, and 18 months. Functional findings were compared between the two techniques and correlated with asthma control, OCS use, exacerbations, hospitalizations, and healthcare utilization.

Significant clinical improvement was observed over 18 months, with reductions in exacerbations, hospitalizations, healthcare utilization and OCS use, alongside improved ACT scores. FEF25-75% showed partial functional improvement and significant correlations with IOS indices, particularly R5-R20 (r=-0.52 to -0.65) and AX (r=-0.30 to -0.54), supporting the complementary role of oscillometry in longitudinal assessment.

Biologic therapy significantly reduced the clinical burden of severe asthma. IOS may provide complementary information alongside spirometry for longitudinal functional monitoring in real-life setting.