Relationship between Bronchial Hyperresponsiveness and Development of Asthma in Preschool Children with Cough Variant Asthma / 소아알레르기및호흡기학회지

ABSTRACT

PURPOSE: A significant proportion of patients with cough variant asthma (CVA) eventually develops asthma. The aim of this study was to investigate the relationship between bronchial hyperresponsiveness (BHR) and development of asthma in preschool children with CVA. METHODS: We reviewed the medical records of children aged 5 to 7 years who presented with chronic cough and had regular check-up by the school age. All children had methacholine bronchial challenge test (MBCT) at preschool age with a modified auscultation method. The end-point was defined as the appearance of wheezing and/or oxygen desaturation. Positive BHR was defined as end-point concentration (EPC)< or =8 mg/mL. MBCT was performed at the school age with spirometric method. Positive BHR was defined as PC20< or =8 mg/mL. We collected information on the development of wheezing or dyspnoea from the medical records. RESULTS: Thirty-six children with CVA were analyzed. During follow-up (2.1+/-0.9 years), 9/36 children developed wheezing or dyspnoea (group A), and 27/36 children did not (group B). EPC (geometric mean, 95% confidence interval) was significantly lower in group A than group B (1.59 mg/mL, 0.93 to 2.70 mg/mL vs. 3.43 mg/mL, 2.34 to 5.03 mg/mL; P=0.02, respectively). The prevalence of positive BHR at school age was significantly higher in group A than group B (77.8% vs. 22.2%, P<0.01). CONCLUSION: These results suggest that the increase and the persistence of BHR may have an important role in the development of asthma during the course of CVA in preschool children.