Prognostic impact of sleep disordered breathing and its treatment in heart failure: an observational study.

AIMS: Sleep disordered breathing (SDB) may contribute to disease progression in patients with chronic heart failure (CHF). The objective of this observational study was to evaluate whether SDB is a risk factor for mortality in CHF patients and whether this risk can be attenuated by treatment with positive airway pressure (PAP). METHODS AND
RESULTS: We studied 296 CHF patients (median left ventricular ejection fraction 33%) who underwent in-lab polysomnography between January 2002 and December 2009. We compared (i) mortality between patients with severe SDB [apnoea-hypopnoea index (AHI) ≥ 22.5 h(-1)] vs. those without severe SDB (AHI < 22.5 h(-1)) and (ii) evaluated the impact of PAP treatment on mortality in those with severe SDB. After accounting for significant confounding factors (age, NYHA class, cause of CHF, diabetes, and PAP treatment), patients with severe SDB (n= 176) had a 2.0-fold increased hazard ratio for death compared with those without severe SDB [95% confidence interval (CI) 1.1-3.5, P= 0.023]. In an adjusted on-treatment analysis of the group with severe SDB, mortality was significantly less in patients using PAP (18%) compared with those with untreated SDB (52%; hazard ratio 0.4, 95% CI 0.2-0.6, P= 0.001). Mortality in the PAP-treated group was lower compared with the untreated group at any time-point of the follow-up period.
CONCLUSION: The presence of severe SDB in CHF patients constitutes a significantly increased risk for death, independent of established risk factors. In CHF patients with SDB, use of PAP therapy was associated with a decreased mortality rate at any time point of the follow-up, suggesting that PAP can be safely used in such patients.