This study sought to identify the risk of sudden cardiac death (SCD) associated with
obstructive sleep apnea (OSA).
Risk stratification for SCD, a major cause of mortality, is difficult. OSA is linked
to cardiovascular disease and arrhythmias and has been shown to increase the risk
of nocturnal SCD. It is unknown if OSA independently increases the risk of SCD.
We included 10,701 consecutive adults undergoing their first diagnostic polysomnogram
between July 1987 and July 2003. During follow-up up to 15 years, we assessed incident
resuscitated or fatal SCD in relation to the presence of OSA, physiological data including
the apnea-hypopnea index (AHI), and nocturnal oxygen saturation (O2sat) parameters,
and relevant comorbidities.
During an average follow-up of 5.3 years, 142 patients had resuscitated or fatal SCD
(annual rate 0.27%). In multivariate analysis, independent risk factors for SCD were
age, hypertension, coronary artery disease, cardiomyopathy or heart failure, ventricular
ectopy or nonsustained ventricular tachycardia, and lowest nocturnal O2sat (per 10%
decrease, hazard ratio [HR]: 1.14; p = 0.029). SCD was best predicted by age >60 years
(HR: 5.53), apnea-hypopnea index >20 (HR: 1.60), mean nocturnal O2sat <93% (HR: 2.93),
and lowest nocturnal O2sat <78% (HR: 2.60; all p < 0.0001).
In a population of 10,701 adults referred for polysomnography, OSA predicted incident
SCD, and the magnitude of risk was predicted by multiple parameters characterizing
OSA severity. Nocturnal hypoxemia, an important pathophysiological feature of OSA,
strongly predicted SCD independently of well-established risk factors. These findings
implicate OSA, a prevalent condition, as a novel risk factor for SCD.
Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier
Inc. All rights reserved.