A clinical study to determine the threshold of bronchodilator response for diagnosing asthma in Chinese children.World J Pediatr 2019WJ
There is few objective, clinically feasible and inexpensive test for diagnosing childhood asthma. We want to find an ideal way to solve it.
The control group was 301 non-asthmatic children, and the asthma group was 286 asthmatic children. The asthmatic children were divided into three groups according to the severity of their disease. Pre- and post-bronchodilator spirometer tests were performed, and the main spirometer parameters were compared. The bronchodilator response (BDR) [BDR is used to determine the reversibility of airway obstruction by measuring the changes of forced expiratory volume in the first second (FEV1) before and after inhalation of bronchodilators] was then determined, and the optimal threshold of BDR for diagnosing childhood asthma was found.
301 non-asthmatic children and 286 asthmatic children participated in the study, the demographics were similar. FEV1 for pre-bronchodilator of asthmatic children was significantly lower than that of non-asthmatic children (P ≤ 0.01). BDR of non-asthmatic children was 3.30 ± 3.85%. BDR of asthmatic children was 9.45 ± 9.15%. There was no significant difference in BDR for patients with different severities of asthma within the group. BDR had no statistical correlation with gender, age, height, weight in neither non-asthmatic children nor asthmatic children. On the receiver-operating characteristic curve, a BDR threshold of ≥ 7.5% offered an optimal balance in asthma diagnosis with a sensitivity rate of 50.7% and specificity rate of 87.7%. Meanwhile, with a BDR threshold of ≥ 12%, the sensitivity rate was 28.7% and the specificity rate was 96.3%.
A BDR threshold of ≥ 7.5% has more value in childhood asthma diagnosis as compared to ≥ 12%.