Utility of MostGraph in asthma management: Comparative study with cough-variant asthma

Non-invasive methods for detailed evaluation of airway pathology in asthma, including structural airway abnormalities, remain limited, and accurate assessment is still insufficient. The MostGraph, which utilizes the impulse oscillation system (IOS), allows non-invasive measurement of airway resistance and reactance. This study evaluated its utility in distinguishing airway pathology between bronchial asthma (BA) and cough variant asthma (CVA), with a focus on peripheral airway involvement.

In this cross-sectional study, 383 patients with stable respiratory symptoms for over three months were enrolled (203 BA, 180 CVA). All patients underwent spirometry, IOS assessment using the MostGraph, blood tests, and fractional exhaled nitric oxide (FeNO) measurement.

Body composition was comparable between groups, although BA patients were older. BA showed significantly greater airway obstruction (%FEV₁/predicted FEV₁) and peripheral impairment (V50/V25, MMF). R5-R20 values were higher in BA than CVA before and after bronchodilator use. In BA, R5, R20, and R5-R20 correlated significantly with %FEV₁; in CVA, only R5 and R20 did. R5-R20 showed no correlation (R = -0.11, P = 0.14). Inspiratory R5-R20 was not correlated in CVA (Pre-BD: R = -0.048, P = 0.53; Post-BD: R = -0.13, P = 0.091), while all parameters correlated in BA. Fres was significantly higher in BA both pre- and post-bronchodilator (P < 0.0001).

MostGraph indices, when integrated with spirometry, may offer a valuable non-invasive approach for characterizing peripheral airway abnormalities that may reflect remodeling-related changes in BA and support airway monitoring in asthma management.

UMIN-CTR Clinical Trial (UMIN000054006). (https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000061647).