Abstract Rationale Children with obesity are at high risk of sleep disordered breathing, with prevalence over 40%. In-laboratory polysomnography (PSG) is the gold standard for diagnosis but is limited in accessibility, with wait times often over 12 months. Alternative approaches are needed to improve timely care. Ambulatory level III sleep devices have shown accuracy in adults and could serve as triage tools, but their performance in children with obesity has not been validated in larger cohorts. This study evaluated the diagnostic accuracy and agreement of the NOX device compared with PSG in children with obesity to enhance access to sleep assessment and reduce waiting times. Methods Children aged 10-18 years with obesity referred for sleep evaluation at the Hospital for Sick Children, Toronto, Canada underwent both in-laboratory PSG and ambulatory level III (NOX) testing within 14 days, in random order. Key sleep parameters—including total sleep time (TST), obstructive apnea-hypopnea index (OAHI), central apnea-hypopnea index (CAHI), desaturation index, and oxygen saturation (SpO2)—were compared using paired t-tests or Wilcoxon signed-rank tests. Agreement between PSG and NOX metrics was assessed via Bland-Altman analysis. PSGs were performed and scored per the American Academy of Sleep Medicine criteria, with all NOX recordings being manually scored by a sleep technologist. The study protocol was approved by the Research Ethics Board. Results Thirty-one children were included (mean (standard deviation, SD) age 12.3 (3.7) years; mean BMI 37.3 (9.4) kg/m²), with 54.8% male. Significant differences were noted for OAHI (median (interquartile range, IQR) 6.2 (2.5-17.8) vs. 2.8 (0.3-6.9) events/h, p 0.0001), average SpO2 (median (IQR) 96.6 (1.5) % vs. 94.4 (2.2) %, p 0.0001), and minimum SpO2 (mean (SD) 85.4 (1.5) % vs. 80.0 (2.2) %, p = 0.007). No significant differences were observed between PSG and NOX metrics for TST (p = 0.3), CAHI (p = 0.6), or desaturation index (p = 0.2). Bland-Altman analysis revealed a mean OAHI difference of 8.9 events/h (95% limits of agreement −30.3 to + 48.3) and CAHI difference of − 0.6 events/h (−12.3 to + 11.1). Based on NOX results, 10 participants (32%) had an AHI 5 events/hour, compared with 19 participants (61.3%) on PSG. Conclusions The NOX device provided results comparable to PSG for several sleep parameters but underestimated OAHI, limiting its standalone diagnostic reliability. Its feasibility and partial diagnostic accuracy support its use as a triage tool to prioritize children for PSG, improving access, enabling earlier intervention for obesity-related SDB, and reducing morbidity. This abstract is funded by: None
Iamwat et al. (Fri,) studied this question.