INTRODUCTION
Obstructive sleep apnea (OSA) is highly prevalent in children with asthma, and is thought to contribute to poorer asthma control1–3. Similarly, asthma has been shown to increase the likelihood of OSA4,5, thus leading to a potential spiraling cascade of cumulative morbidity. The global increasing trend in childhood obesity6,7 also portends a future with a higher burden of OSA, which can further elevate the risk for worse asthma control. OSA risk stratification in children with asthma is therefore imperative and offers an opportunity to mitigate OSA related health consequences, yet there are currently no reliable methods for identifying children with asthma at risk for OSA.
Both asthma and OSA can lead to nocturnal breathing difficulties, sleep disturbance and daytime sleepiness, which are symptoms elicited in OSA screening questionnaires. The sleep related breathing disorders (SRBD) survey, derived from the Pediatric Sleep Questionnaire, is the most common screening tool for OSA in children. It has an OSA screening sensitivity of 78% and specificity of 72% in the general population8. A recent study that validated the SRBD survey in children with asthma found an OSA screening sensitivity of 81% and specificity of 14%, with a maximum negative predictive value of 64% and positive predictive value of 29% at an OSA cutoff of two events per hour2. The low OSA screening accuracy of the SRBD in children with asthma might be due to an overlap in the symptoms caused by asthma and OSA. In fact, previous studies have shown that children with asthma have high SRBD scores, particularly those with poor asthma control9,10. As such, a closer look at the twenty-two questions of the SRBD survey may reveal the OSA risk factors or symptoms beneficial for accurate initial OSA screening in children with asthma.
Our goal was to identify the questions on the SRBD survey useful for predicting OSA in a cohort of children with asthma in order to develop a simple but accurate tool for wide scale OSA risk stratification. Children with asthma enrolled in the AIRWEIGHS study, underwent an in-laboratory overnight sleep study and completed the SRBD survey, providing a unique opportunity to address this research goal.