Abstract 505: Obstructive Sleep Apnea Increases the Risk of Sudden Cardiac Death: A Longitudinal Study of 10,701 Adults
Risk stratification for sudden cardiac death (SCD), a major cause of mortality, is difficult. Obstructive sleep apnea (OSA) is linked to cardiovascular disease and arrhythmias, and is associated with a heightened risk of nocturnal SCD. We hypothesized that OSA independently increases the risk of SCD. We included 10,701 consecutive adults undergoing their first diagnostic polysomnogram between 7/1987 and 7/2003. During follow-up up to 15 years, we assessed incident resuscitated or fatal SCD in relationship 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%, HR 1.14, P=0.029). SCD was best predicted by age 60 years (HR 5.53), AHI 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.