Influence of obstructive sleep apnea on mortality in patients with heart failure.
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.
Wang
Hanqiao
H
Sleep Research Laboratory of the Toronto Rehabilitation Institute, Toronto, Ontario, Canada.
Parker
John D
JD
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.
Newton
Gary E
GE
Department of Medicine of the Mount Sinai Hospital, Toronto, Ontario, Canada.
Floras
John S
JS
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.
Mak
Susanna
S
Department of Medicine of the Mount Sinai Hospital, Toronto, Ontario, Canada.
Chiu
Kuo-Liang
KL
Sleep Research Laboratory of the Toronto Rehabilitation Institute, Toronto, Ontario, Canada.
Ruttanaumpawan
Pimon
P
Sleep Research Laboratory of the Toronto Rehabilitation Institute, Toronto, Ontario, Canada.
Tomlinson
George
G
Department of Medicine of the Toronto General Hospital/University Health Network, Toronto, Ontario, Canada.
Bradley
T Douglas
TD
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.
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