Is it the apnea-hypopnea index or hypoxemia in obstructive sleep apnea?

There has been great controversy as to whether apnea-hypopnea index (AHI) or hypoxemia has a greater impact on the occurrence of adverse sequelae in obstructive sleep apnea (OSA). The Clinical Research NetWork highlight some of the salient studies evaluating the impact of AHI and oxygen saturation on the adverse consequences of OSA below.


  1. Does AHI Value Enough for Evaluating the Obstructive Sleep Apnea Severity?
  2. This study found that nocturnal hypoxemia predicted daytime sleepiness in patients with similar AHI values. The study concluded that AHI is not enough to predict daytime sleepiness in OSA patients.
  3. Obstructive Sleep Apnea and the Risk of Sudden Cardiac Death A Longitudinal Study of 10,701 Adults
  4. This study found that nocturnal hypoxemia, strongly predicted risk of sudden cardiac death independently of well-established risk factors.
  5. Severity of OSA is an Independent Predictor of Incident Atrial Fibrillation Hospitalization in a Large Sleep-clinic Cohort
  6. This study showed that after multivariate analysis, AHI and hypoxemia were independent predictors of incident atrial fibrillation.
  7. Intermittent Hypoxemia and OSA: Implications for Comorbidities
  8. This article highlights the importance of the intermittent hypoxemia seen in OSA in the causation of OSA co-morbidities.
  9. The Association Between Obstructive Sleep Apnea and Neurocognitive Performance--The Apnea Positive Pressure Long-term Efficacy Study (APPLES)
  10. This study found weak correlations between AHI and several indices of oxygen desaturation and neurocognitive performance in unadjusted analyses. However, after adjustment for level of education, ethnicity, and gender, there was no association between the AHI and neurocognitive performance. Severity of oxygen desaturation was weakly associated with worse neurocognitive performance on some measures of intelligence, attention, and processing speed.
  11. Nocturnal Hypoxemia Due to Obstructive Sleep Apnea Is an Independent Predictor of Poor Prognosis After Myocardial Infarction
  12. This study found that in a multivariate model nocturnal hypoxemia in OSA was an important predictor of poor prognosis for patients after myocardial infarction (MI). The authors suggested that routine use of low-cost nocturnal oximetry may be an economical and practical approach to stratify risk in post-MI patients.
  13. Association of Diabetic Microvascular Complications and Parameters of Obstructive Sleep Apnea in Patients With Type 2 Diabetes
  14. This study showed that parameters of nocturnal hypoxemia are associated with diabetic nephropathy and renal function in patients with type 2 diabetes. The authors concluded that parameters of hypoxemia may more sensitively reflect the association of OSA and diabetic microvascular complications than AHI.
  15. Thus, multiple studies have shown that the intermittent episodic hypoxemia of OSA may be perhaps more important than AHI in predicting the complications of OSA. Future studies should evaluate the efficacy of interventions targeted at mitigating the effects of hypoxemia on the adverse sequelae of OSA.