Introduction
Obstructive sleep apnea (OSA) is a prevalent and highly heterogeneous disease with diverse pathophysiological features and neural regulatory mechanisms, which complicates its diagnosis and treatment.1 The global prevalence of OSA continues to rise, but is often underestimated.2 Approximately 1 billion people worldwide suffer from mild to severe OSA.3
Historically, AHI has been the main tool for diagnosing OSA and classifying its severity.4 However, with the exploration of research in areas such as hypoxia, arousal threshold, and loop gain, the limitations of AHI have attracted increasing attention.5–7 The index only quantifies the frequency of apnea-hypopnea events during sleep and does not accurately reflect the duration of these events.8,9 Some studies have also described the poor performance of the…