Sleep Apnea-Specific Hypoxic Burden, Symptom Subtypes, and Risk of Cardiovascular Events and All-Cause Mortality

Area of Science:

• Cardiology
• Sleep Medicine
• Epidemiology

Background:

• Population studies suggest symptom subtypes and hypoxic burden (HB) in obstructive sleep apnea (OSA) can identify patients at high cardiovascular (CV) risk.
• Clinical validation of these markers is needed to assess their association with major adverse CV events (MACE).

Purpose of the Study:

• To evaluate the association of OSA symptom subtypes and HB with the risk of MACE in a clinical cohort.
• To determine if these markers can identify patients with newly diagnosed OSA and no prior CV disease at high risk for future CV events.

Main Methods:

• Latent class analysis identified four OSA symptom subtypes.
• Hypoxic burden (HB) was quantified as the area under the desaturation curve.
• Cox proportional hazards models assessed the association of symptom subtypes and HB with MACE over a median follow-up of 78 months.

Main Results:

• Four symptom subtypes were identified: minimally symptomatic, disturbed sleep, excessively sleepy, and moderately sleepy.
• Elevated HB and overall nocturnal hypoxemia were significant predictors of MACE (HR 1.21 and 1.34, respectively).
• The association of HB with MACE was stronger in younger patients and women.

Conclusions:

• In a clinical setting, elevated hypoxic burden in patients with obstructive sleep apnea is associated with an increased risk of cardiovascular events and all-cause mortality.
• OSA symptom subtypes were not independently associated with MACE after adjusting for confounders.