Exploring the indicative role of ACT score in improving lung function in asthmatic children undergoing dust mite immunotherapy.

BACKGROUND: The aim of this study is to explore the indicative role of Asthma Control Test (ACT) score in the use of dust mite immunotherapy for asthmatic children by comparing the recovery of lung function in these children who have different ACT scores with or without undergoing dust mite immunotherapy, and to provide a more accurate and applicable method to select the population for dust mite immunotherapy. METHODS: A total of 200 children diagnosed with asthma who had tested positive for dust mite allergens from February 2019 to January 2021 were divided into the observation group and control group based on whether sublingual immunotherapy (SLIT) for dust mite allergy was incorporated into their regular asthma treatment. These two groups were further subdivided into ACT > 19 and ACT ≤ 19 groups based on the ACT scores before treatment. After 1 year of follow-up, the lung function and fractional exhaled nitric oxide (FeNO) levels of these four groups were compared before and after treatment. RESULTS: A total of 160 asthmatic children completed the study. We found that the observation group with ACT > 19 showed better improvement in forced vital capacity (FVC) (z = -2.338 P = 0.019), forced expiratory volume in one second (FEV1) (t = 3.02 P = 0.007), forced expiratory flow at 50% of FVC (FEF50) (t = 2.807 P = 0.012), and forced expiratory flow at 25% of FVC (FEF25) (t = 3.032 P = 0.007) than the control group with ACT > 19. Moreover, the observation group with ACT ≤ 19 showed significantly better improvement in FVC (z = -3.554 P < 0.001), FEV1 (z = -3.71 P < 0.001),forced expiratory flow at 75% of FVC (FEF75) (z = -3.8 P < 0.001), FEF50 (z = -3.733 P < 0.001), FEF25 (z = -5.593 P < 0.001), maximal mid-expiratory flow (MMEF) (z = -3.930 P < 0.001), and FeNO (z = -2.218 P = 0.027) than the control group with ACT ≤ 19. We found that in the observation group, irrespective of whether ACT > 19 or ACT ≤ 19, there was some improvement in all indicators, but there was no significant difference between the two subgroups. In the control group, patients with ACT > 19 showed significantly less improvement in FEV1 and FEF75 than patients with ACT ≤ 19 (z = -2.567 P = 0.010, t = 2.624 P = 0.010, respectively). CONCLUSIONS: Immunotherapy for dust mites is effective in improving lung function in children with asthma, especially in those with ACT > 19 before treatment.