Pulmonary function characteristics in children with suspected asthma:
implications for asthma diagnosis
Abstract
Background: In children suspected of asthma, diagnosis is confirmed via
variable expiratory airflow limitation. This study aimed to evaluate the
pulmonary function characteristics in children suspected of asthma
without bronchodilator response (BDR) and bronchial hyperresponsiveness
(BHR). Method: We utilised two separate retrospective observational
cohorts of children who underwent spirometry and bronchial provocation
testing for asthma. Spirometry parameters were collected and compared
between definite asthma, probable asthma, and non-asthma groups. The
original cohort comprised 1199 children who visited the Severance
Hospital (Seoul, Korea) between January 2017 and December 2019. The
external cohort included 105 children who visited the Gangnam Severance
Hospital between January 2000 and December 2017. Result: Probable asthma
accounted for 16.8% and 32.4% of the original and external cohorts,
respectively. Baseline forced expiratory volume in 1 second (FEV1),
FEV1/forced vital capacity (FVC), forced expiratory flow at 25-75% of
FVC (FEF25-75), and FEF75 showed stepwise decrements from non-asthma,
probable asthma, to definite asthma patients (P < 0.001). The
probable asthma group showed significantly higher odds of abnormal
FEV1/FVC (OR, 2.24 [95%CI, 1.43-3.52]) and FEF25-75 (OR, 2.05
[95%CI, 1.13-3.73]) than the non-asthma group and lower odds of
abnormal FEV1 (OR, 0.05 [95%CI, 0.01-0.19]), FEV1/FVC (OR, 0.27
[95% CI, 0.18-0.41]), FEF25-75 (OR, 0.17 [95%CI, 0.11-0.28]),
and FEF75 (OR, 0.14 [95%CI, 0.08-0.24]) compared to the definite
asthma group. The external cohort was consistent with the original
cohort. Conclusion: We show evidence of airway dysfunction in children
for whom a high clinical suspicion of asthma exists without evidence of
BDR and BHR.