Moderate obstructive sleep apnea can significantly increase risk of sudden cardiac death, a study found.
Researchers examined the relationship between sleep apnea and sudden cardiac death, building off of their prior study that found people with sleep apnea more frequently died suddenly from cardiac causes between 10 p.m. and 6 a.m., which is the least likely time for sudden cardiac death in the general population.
Researchers followed 10,701 subjects for an average of 5.3 years for incidents of resuscitated or fatal sudden cardiac death. Results appeared online June 11 at the Journal of the American College of Cardiology.
During the study, 142 patients experienced sudden cardiac death (annual rate 0.27%)., with the most common predictors being 60 years of age (hazard ratio [HR], 5.53), having 20 apnea episodes an hour (HR, 160), mean nocturnal oxygen saturation of 93% (HR, 2.93), and lowest nocturnal oxygen saturation of 78% (HR, 2.60), the last of which raised risk of sudden cardiac death by 80% (all P less than 0.0001).
Researchers noted that sleep apnea patients' risk of sudden cardiac death does not simply shift from day to night but that their overall risk of sudden cardiac death is higher than people without sleep apnea. "Our present findings suggest that this increase of SCD (sudden cardiac death) during the night may represent 'excess' deaths, rather than simply a shift of SCD from other times of the day to the night."