Differential sleep architecture in different subtypes of positional obstructive sleep apnea in children

Study objectives: This study aimed to compare the clinical characteristics of two types of positional obstructive sleep apnea (POSA) in children: supine dominant OSA (spOSA) and supine isolated OSA (siOSA). The goal was to investigate the differences in sleep structures between the two groups. Methods: A total of 384 children with OSA were included. Children with POSA were categorized into two subgroups: siOSA for those with a non-supine AHI <1, and spOSA for those with a non-supine AHI >= 1. Clinical characteristics and polysomnographic features were compared between the two groups. Results: Among the 384 patients with OSA, 128 (33.3 %) were classified as POSA. Weight, BMI, and BMI Z-scores were higher in the POSA group compared to the non-POSA group (NPOSA). Polysomnography (PSG) data indicated that total sleep time (TST) and N2 % were higher in the POSA group than in the NPOSA group. Minimum SaO(2) was lower in the POSA group, and oxygen desaturation index(ODI)values were higher compared to the NPOSA group. The rate of overweight and obesity was higher in the POSA group. Among the 128 POSA cases, 47 (36.7 %) were classified as spOSA and 81 (63.3 %) as siOSA. The siOSA patients were younger than those in the spOSA group. SiOSA patients had a higher N2 %, lower R %, and lower AHI, AHI(NREM), AHI(REM), OAHI, HI, and ODI compared to spOSA patients. The spOSA group had a higher rate of severe OSA compared to the siOSA group. Conclusion: This study found significant differences between children with spOSA and siOSA. The spOSA group had higher values in AHI-related parameters. The spOSA group also showed a higher rate of moderate-to-severe OSA. In contrast, the siOSA group had younger age. Additionally, the siOSA group displayed abnormal sleep architecture: higher N2 % and lower R %. These differences suggest distinct pathological mechanisms may exist between the two subtypes. Therefore, targeted clinical strategies should be developed for each subtype.