How is the severity of obstructive sleep apnea classified?

The severity of obstructive sleep apnea (OSA) is classified primarily based on the Apnea-Hypopnea Index (AHI). The AHI is a crucial metric that quantifies the number of apneas (complete airway obstruction) and hypopneas (partial airway obstruction) occurring per hour of sleep. This index allows clinicians to categorize the severity of OSA into mild, moderate, and severe based on specific cut-off values. For instance, an AHI of 5 to 15 indicates mild OSA, 15 to 30 indicates moderate OSA, and greater than 30 indicates severe OSA.

While oxygen saturation levels, patient reports, and duration of sleep interruptions can provide additional context regarding a patient's condition, they are not standardized classifications of severity for OSA. The AHI remains the most widely accepted and objective measure used in clinical and research settings to assess and classify the severity of the disorder.