title: Obstructive sleep apnea and the risk of sudden cardiac death: a longitudinal study of 10,701 adults.
abstract: OBJECTIVE
  This study sought to identify the risk of sudden cardiac death (SCD) associated with obstructive sleep apnea (OSA).
  
  
  BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Section of Electrophysiology and Pacing, Midwest Heart Specialists-Advocate Medical Group, Elmhurst, Illinois, USA.
authors.forename: Apoor S
authors.initials: AS
authors.lastname: Gami
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Olson
authors.forename: Win K
authors.initials: WK
authors.lastname: Shen
authors.forename: R Scott
authors.initials: RS
authors.lastname: Wright
authors.forename: Karla V
authors.initials: KV
authors.lastname: Ballman
authors.forename: Dave O
authors.initials: DO
authors.lastname: Hodge
authors.forename: Regina M
authors.initials: RM
authors.lastname: Herges
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Howard
authors.forename: Virend K
authors.initials: VK
authors.lastname: Somers
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D002423:Cause of Death; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017286:Polysomnography; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D017678:Sex Distribution; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy
keywords: AHI; CI; HR; ICD; OSA; SCD; apnea-hypopnea index; arrhythmia; confidence interval; hazard ratio; heart disease; implantable cardioverter-defibrillator; obstructive sleep apnea; risk factor; sleep apnea; sudden cardiac death