Ability of impulse oscillometry to predict loss of asthma control during pollution period in previously stable...

Impulse oscillometry (IOS) is recognized as a sensitive technique for detecting small airway dysfunction (SAD), and previous studies have demonstrated its association with poor asthma control. However, its utility in predicting future asthma control remains uncertain. This study aimed to assess the predictive value of IOS for future asthma control during high pollution periods.

Patients with well-controlled asthma were enrolled. Baseline data collection including spirometry, IOS measurements, and asthma control test (ACT) scores was performed between January and February 2024. ACT scores were reassessed during a subsequent high air pollution period (March-April 2024). The diagnostic accuracy of IOS in forecasting future loss of asthma control was evaluated.

Seventy-nine subjects with a mean age of 60.4 ± 14.0 years, 53 females (67.1%) were included. The mean particulate matter with an aerodynamic diameter less than or equal to 2.5 micrometers (PM_2.5) differed significantly between the nonpollution and pollution periods (21.1 ± 7.8 μg/m³ vs 78.2 ± 31.8 μg/m³, respectively; p < 0.001). Twenty-three participants experienced a loss of asthma control during the pollution period. The area under the receiver operating characteristic curve (AUC) for the %predicted difference between R5 and R20 (R5-R20) in predicting loss of asthma control was 0.39 (95%CI: 0.25, 0.53). Further analysis focusing on %predicted R5-R20 indicated no predictive value for asthma control during periods of high pollution (adjusted RR: 1.00; 95%CI: 0.99, 1.01; p = 0.553).

IOS do not predict loss of asthma control during air pollution period in patients with previously stable asthma.