Correlation Between Pulmonary Function Tests and the Apnea-Hypopnea Index in Asthmatic Children

Abstract

Introduction: OSA in children is an under-recognized and under-diagnosed disease and is an independent risk factor for poor asthma control and an increased number of exacerbations. The association of asthma and OSA is well documented in adults and to a lesser extent in the pediatric population. The association of AHI and lung function in children in a high-altitude city is not described in the literature. Methods: This cross-sectional observational study involved children with asthma (n=64) between 3 and 12 years of age referred to our center in Bogotá (2640m) for polysomnogram between 2012 and 2017. Clinical history, spirometry, oscillometry, and polysomnogram were carried out. OSA was defined from the polysomnographic point of view, as the presence of an obstructive Apnea hypopnea index ≥ 1/hour Results: A total of 64 children with asthma were included. 59.34% were boys and the median age was 7 years. 59.4% of the participants had moderate or severe asthma and 59.4% had uncontrolled asthma. A significant correlation was found between BMI and OAHI. Concerning pulmonary function, a significant negative correlation was found between pre-bronchodilator FEV1 and OAHI as well as a significant correlation between FEV1/FVC and CAHI. For oscillometry, R5 showed a significant negative correlation with AHI. Conclusions: We found in children with asthma living in a high-altitude city a significant and negative correlation between FEV and R5 with AHI as well as a significant and negative correlation between FEV /FVC ratio and CAHI. These findings suggest a correlation between distal airway diameter and sleep apnea severity.