LAUSR

Although the apnea-hypopnea index (AHI) remains the gold-standard metric of the severity of obstructive sleep apnea (OSA), it is often criticized for its limitations. The odds ratio product (ORP), a continuous standardized measure of sleep depth that ranges from 0 (deep sleep) to 2.5 (full wakefulness), has been proposed as a potential EEG-based alternative to assess the severity of OSA, including its association with cardiovascular outcomes such as elevated blood pressure (eBP). We extracted ORP during rapid eye movement (REM) and non-REM sleep stages from the sleep EEG of 421 adolescents (median 16y) from the Penn State Child Cohort. Higher ORP indicates lower sleep depth. Systolic and diastolic BP levels were measured in the seated position and eBP was identified using American Heart Association guideline-recommended pediatric criteria. OSA was defined as an AHI of 2 or greater events per hour of sleep. Logistic regression models examined the joint of effect of AHI and ORP on eBP, while adjusting for sex, age, race/ethnicity and body mass index, and stratified by the presence of OSA. We found a significant interaction between AHI and ORP on eBP (p-interaction=0.016). Among adolescents with OSA, each additional 0.5-point increase in ORP was associated with 6.3-fold odds (95%CI=1.9-20.6, p=0.003) of eBP. Specifically, each additional 0.5-point increase in ORP was associated with 6.4 mmHg (SE=3.0, p=0.036) higher systolic BP among adolescents with OSA. These associations were not significant among adolescents without OSA (eBP: OR=0.8, 95%CI=0.4-1.8, p=0.602 for each additional 0.5 increase in ORP). Our data support ORP as a prognostic sleep-EEG metric of OSA in youth. Future clinical trials should examine the added value of ORP in OSA endophenotyping, its response to treatment and role in improving cardiovascular outcomes. National Institutes of Health (R01HL136587, R01MH118308, UL1TR000127)