What is the threshold for diagnosing sleep apnea?
Sleep apnea is diagnosed by polysomnography to calculate the apnea-hypopnea index (AHI), the hourly sum of apneas (total cessation of airflow for 10 seconds) plus hypopneas (reduction in airflow by at least 30% for 10 seconds with reduced oxygen saturation). The threshold for diagnosis is AHI 5 with symptoms (eg, sleepiness) or Theprevalenceofmoder- ate to severe sleep apnea (AHI >15) among US adults 50 to 70 years of age is estimated to be 10%.318 Prevalence is higher in men than women and increases sharply with age and BMI.