Influence of obstructive sleep apnea on mortality in patients with heart failure

Objectives 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) <= 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 >= 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.