What is the key indicator for diagnosing sleep apnea severity?

The Apnea-Hypopnea Index (AHI) is the key indicator for diagnosing the severity of sleep apnea because it quantitatively measures the frequency of apneas (complete cessation of breathing) and hypopneas (partial cessation of breathing) during sleep. The AHI provides a clear and standardized way to assess the severity of sleep-disordered breathing by calculating the number of episodes per hour of sleep. This index helps clinicians categorize sleep apnea into mild, moderate, or severe, which is essential for determining appropriate treatment options and monitoring the condition's progression.

Other metrics, such as the Respiratory Disturbance Index, the Sleep Efficiency Ratio, and the Sleep Latency Measure, do not specifically focus on the events related to apnea and hypopnea. While these metrics may provide additional information regarding a patient's overall sleep quality or disruptions, they lack the specificity that the AHI provides regarding the severity of obstructive sleep apnea. Consequently, AHI remains the gold standard for diagnosing and assessing sleep apnea severity.