Prevalence and Risk Factors of Positional Obstructive Sleep Apnea in Chinese Children: A Retrospective Study.

Objective: To investigate the prevalence, characteristics, risk factors, and clinical outcomes of positional obstructive sleep apnea (POSA) in Chinese children. Methods: This was a retrospective analysis of children aged 4-17 years with OSA from local referrals for sleep-disordered breathing. Children who underwent diagnostic polysomnography (PSG) with at least 30 minutes of total sleep time in both supine and non-supine sleep were included. Standardized sleep questionnaires, Sleepiness Scales, Child Behavior Checklist and 24-hour ambulatory blood pressure monitoring were completed. OSA was defined as obstructive apnea-hypopnea index (OAHI) ≥1/h. POSA was defined as OAHI in the supine position ≥ two times the OAHI in the non-supine position. Results: 314 children (mean age: 10.88±3.22 years; male: 70%) with OSA were analyzed, of whom 147 (46.8%) had moderate/severe OSA (OAHI≥5). Prevalence of POSA was 58% within our cohort and 51% among those with moderate/severe OSA. Children with POSA were older (10.8±3.3 years vs 9.1±2.6 years; p<0.001), had milder disease [OAHI 4.12 (2.14-8.62) events/h vs 6.16 events/h); p=0.026] and had smaller tonsillar size (55% vs 72%; p=0.011). By logistic regression, POSA was associated with older age (OR 1.20; 95% confidence interval (CI) 1.09-1.32; p<0.001) and lower OAHI (B-0.036; SE 0.011; OR 0.964; 95% CI 0.943-0.986; p=0.001). Conclusion: POSA is a prevalent phenotype seen in children, demonstrating strong associations with older age, more mature pubertal development, smaller tonsillar size and milder disease severity. Future studies should also delineate the natural history and longitudinal stability of this subtype over time.