Long-term trajectories of lung function and risk factors in children with bronchial asthma / 中华实用儿科临床杂志

ABSTRACT

Objective:To establish the long-term trajectories of lung function in children with bronchial asthma (asthma) and explore the risk factors of persistent pulmonary dysfunction.Methods:A retrospective cohort study was conducted.Children with asthma aged above 14 years who had been followed up regularly and completed pulmonary function testing in Children′s Hospital of Capital Institute of Pediatrics were enrolled in the study from January to December 2019.Their lung function data and clinical information were collected.The latent class growth model (LCGM) was used to fit the change of lung function in children with asthma, and different trajectory groups were established.Comparison between groups was performed by t-test, ANOVA or Chi- square test.The risk factors for the lung function trajectory were analyzed by the multivariate Logistic regression method. Results:A total of 173 children with asthma, aged from 6 to 17, were enrolled, and 1 160 lung function tests were completed.Four forced expiratory volume in the first second/forced vital capacity (FEV 1/FVC) latent class trajectory groups were established, including persistent high level [27 cases (15.6%)], above average level [66 cases (38.1%)], below average level [66 cases (38.1%)], and persistent low level [14 cases (8.1%)]. In all the 4 different trajectory groups, the FEV 1/FVC values were significantly different among patients of different ages (all P<0.05). The FEV 1/FVC values of patients at all ages in the persistent high level group were above 90%.The FEV 1/FVC values of patients in other 3 level groups decreased as a whole as the age increased.FEV 1/FVC of patients in the persistent low level group decreased to below 80% when they entered the school age period and approached 70% in adolescence.The trajectory and fluctuation of maximal midexpiratory flow (MMEF), which represents the small airway function, were similar to those of FEV 1/FVC.Risk factor analysis showed that the risk of lung function decreasing below the average level in children with typical asthma was 11.940 times higher than that in children with cough variant asthma ( P=0.008). The risk of lung function deteriorating to below the average level in children with multiple allergen sensitivities was 7.462 times higher than that in children with single allergen sensitivity ( P=0.015). Children taking drugs irregularly were 6.337 times more likely to suffer persistent low lung function than children taking drugs regularly ( P=0.035). Boys were 6.186 times more likely to suffer a lung function reduction to below the average level than girls ( P=0.002). Conclusions:Four long-term trajectories of lung function in asthmatic children aged 6 to 17 years can be established persistent high level, above average level, below average level and persistent low level.The long-term lung function of nearly a half of the asthmatic children is below the average level.Many children develop persistent airflow limitation in adolescence, and few at school age.Typical asthma, multiple allergen sensitivities, irregular medication and boy were the risk factors of long-term lung function reduction.