Apnea-hypopnea duration may be a better choice rather than apnea-hypopnea index for forecasting complications in OSAS.

Objective: Mean apnea-hypopnea duration (AHD) is the mean duration of apnea-hypopneas experienced during sleep and was found as an indicator of blood oxygenation. The aim of this study was to compare and define the differences in clinical, demographic and polysomnographic characteristics of obstructive sleep apnea (OSA) patients in long and short AHD groups and investigate the relationship between apnea-hypopnea index (AHI), oxygen desaturation index (ODI), and sleepiness.

Methods: The cross-sectional analysis included 511 OSA patients who were >18 years and followed up between June 2019 and December 2019 in the Sleep Center of university hospital. The consecutive polysomnography reports and patient data were recorded retrospectively.

Results: Polysomnographic evaluation of different AHD groups showed obvious differences. Although there were no statistically significant differences in the overall AHI values. The Epworth measurements, ODI, time that saturation is below 90%, and N1 and N2 sleep were higher in the long AHD group. On the contrary, sleep efficiency, total sleep time, N3 and REM sleep, average oxygen saturation (AOS), and lowest oxygen saturation (LOS) were lower in the long AHD group.

Conclusions: The findings of this study showed that the AHD is a useful indicator of blood oxygenation and, therefore, tissue oxygenation, independent of the AHI. OSA patients with longer AHD have more vascular complications such as diabetes and hypertension. We suggest that the severity of OSA should be monitored with AHD for preventing potential complications of OSA.