Positional Obstructive Sleep Apnea: A Model for Precision Sleep Medicine.

Positional obstructive sleep apnea (POSA) is a subtype of obstructive sleep apnea in which the apnea-hypopnea index (AHI) is significantly greater in the supine position than in non-supine positions. However, POSA remains underrecognized and lacks a universally accepted clinical definition. POSA's prevalence can exceed 50% of OSA patients and occurs most frequently in patients with mild/moderate disease. In the supine position, gravity-dependent posterior displacement of the tongue and soft palate can increase upper airway collapsibility and drive the pathophysiology of POSA. These disturbances can carry meaningful cardiovascular consequences, including acute blood pressure surges that correlate with oxygen desaturation severity. As OSA is increasingly understood as a heterogeneous disorder shaped by variable anatomical and physiological traits, POSA offers a clinically actionable framework for precision sleep medicine. Current therapeutic strategies demonstrate that targeting the specific mechanisms of POSA can improve outcomes beyond what standardized CPAP treatment achieves alone. Racial and ethnic disparities in both POSA prevalence and treatment adherence further highlight the importance of individualized, culturally informed care. This review synthesizes the current understanding of the mechanisms, epidemiology, and therapeutic implications of POSA and evaluates its role as a model for individualized therapy in obstructive sleep apnea treatment.