How to rate the severity index in obstructive sleep apnea

Currently, obstructive sleep apnea (OSA) is defined as having an apnea-hypopnea index (AHI) of 5 events per hour. The AHI is based on the frequency of respiratory events over time and is used to predict disease severity and guide therapeutic interventions. However, the AHI fails to capture the substantial heterogeneity present in OSA, including patterns of hypoxemia, sympathetic response, and gender differences. In recent years, multiple metrics derived from pulse oximeter signals, heart rate, electroencephalogram, and ventilation signals have been described. This article will focus on those metrics that have been validated through external studies and possess greater clinical relevance.