How is the apnea-hypopnea index (AHI) used in the diagnosis of obstructive sleep apnea (OSA)?

Updated: Mar 22, 2019
  • Author: Himanshu Wickramasinghe, MD, MBBS; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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Answer

The apnea-hypopnea index (AHI) is derived from the total number of apneas and hypopneas divided by the total sleep time. A normal cutoff for AHI has never been defined in an epidemiological study of healthy people. Most sleep centers use a cutoff of 5-10 episodes per hour. The severity of OSA is arbitrarily defined and differs widely between centers. Recommendations for cutoff levels on AHI include 5-15 episodes per hour for mild, 15-30 episodes per hour for moderate, and more than 30 episodes per hour for severe.


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