The correlation between oxygen saturation indices and the standard obstructive sleep apnea severity

Area of Science:

• Sleep Medicine
• Respiratory Physiology

Background:

• Current obstructive sleep apnea (OSA) severity classification relies on the Apnea-Hypopnea Index (AHI).
• The clinical validity of AHI in defining OSA severity requires further investigation.

Purpose of the Study:

• To evaluate the concurrent validity of the AHI by correlating it with various oxygen saturation (SpO2) and polysomnographic parameters.
• To assess the reliability of the AHI in classifying OSA severity.

Main Methods:

• Utilized data from a Saudi population survey on OSA prevalence (n=2682).
• Included 178 individuals with total sleep times ≥ 240 min and rapid eye movement (REM) sleep from polysomnography data.
• Compared standard OSA severity classification with SpO2 and polysomnographic parameters.

Main Results:

• Direct correlations were found between AHI-based OSA severity and desaturation index (DI), desaturation below 90%, respiratory event duration, and arousal indices (P < 0.001).
• REM sleep duration and SpO2 nadir showed inverse correlations with OSA severity (P < 0.003 and P < 0.001, respectively).
• DI, SpO2 nadir, and respiratory arousal index were identified as predictors of OSA severity via logistic regression.

Conclusions:

• Findings support the clinical reliability of the AHI for classifying OSA severity.
• The AHI remains a valid tool for assessing obstructive sleep apnea severity in clinical practice.