title: Influence of obstructive sleep apnea on mortality in patients with heart failure.
abstract: OBJECTIVE
  This study sought to determine, in patients with heart failure (HF), whether untreated moderate to severe obstructive sleep apnea (OSA) is associated with a higher mortality rate than in patients with mild to no sleep apnea (M-NSA).
  
  
  BACKGROUND
  Obstructive sleep apnea is common in patients with HF and exposes the heart and circulation to adverse mechanical and autonomic effects. However, its effect on mortality rates of patients with HF has not been reported.
  
  
  METHODS
  In a prospective study involving 164 HF patients with left ventricular ejection fractions (LVEFs) < or =45%, we performed polysomnography and compared death rates between those with M-NSA (apnea-hypopnea index [AHI] <15/h of sleep) and those with untreated OSA (AHI > or =15/h of sleep).
  
  
  RESULTS
  During a mean (+/- SD) of 2.9 +/- 2.2 and a maximum of 7.3 years of follow-up, the death rate was significantly greater in the 37 untreated OSA patients than in the 113 M-NSA patients after controlling for confounding factors (8.7 vs. 4.2 deaths per 100 patient-years, p = 0.029). Although there were no deaths among the 14 patients whose OSA was treated by continuous positive airway pressure (CPAP), the mortality rate was not significantly different from the untreated OSA patients (p = 0.070).
  
  
  CONCLUSIONS
  In patients with HF, untreated OSA is associated with an increased risk of death independently of confounding factors.
authors: Sleep Research Laboratory of the Toronto Rehabilitation Institute, Toronto, Ontario, Canada.
authors: Hanqiao
authors: H
authors: Wang
authors: Department of Medicine of the Mount Sinai Hospital, Toronto, Ontario, Canada; Department of Medicine of the Toronto General Hospital/University Health Network, Toronto, Ontario, Canada.
authors: John D
authors: JD
authors: Parker
authors: Department of Medicine of the Mount Sinai Hospital, Toronto, Ontario, Canada.
authors: Gary E
authors: GE
authors: Newton
authors: Department of Medicine of the Mount Sinai Hospital, Toronto, Ontario, Canada; Department of Medicine of the Toronto General Hospital/University Health Network, Toronto, Ontario, Canada.
authors: John S
authors: JS
authors: Floras
authors: Department of Medicine of the Mount Sinai Hospital, Toronto, Ontario, Canada.
authors: Susanna
authors: S
authors: Mak
authors: Sleep Research Laboratory of the Toronto Rehabilitation Institute, Toronto, Ontario, Canada.
authors: Kuo-Liang
authors: KL
authors: Chiu
authors: Sleep Research Laboratory of the Toronto Rehabilitation Institute, Toronto, Ontario, Canada.
authors: Pimon
authors: P
authors: Ruttanaumpawan
authors: Department of Medicine of the Toronto General Hospital/University Health Network, Toronto, Ontario, Canada.
authors: George
authors: G
authors: Tomlinson
authors: Sleep Research Laboratory of the Toronto Rehabilitation Institute, Toronto, Ontario, Canada; Department of Medicine of the Toronto General Hospital/University Health Network, Toronto, Ontario, Canada; Centre for Sleep Medicine and Circadian Biology, University of Toronto, Toronto, Ontario, Canada.. Electronic address: douglas.bradley@utoronto.ca.
authors: T Douglas
authors: TD
authors: Bradley
mesh_terms: D000328:Adult; D017677:Age Distribution; D000704:Analysis of Variance; D016022:Case-Control Studies; D002423:Cause of Death; D015897:Comorbidity; D045422:Continuous Positive Airway Pressure; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012016:Reference Values; D018570:Risk Assessment; D012720:Severity of Illness Index; D017678:Sex Distribution; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy*; D018709:Statistics, Nonparametric; D016019:Survival Analysis