Heart Failure Mortality and Sleep Apnea | Journal Scan
Does sleep-disordered breathing (SDB) impact post-discharge mortality in hospitalized heart failure patients?
Participants were recruited from a single center between January 2007 and December 2010 into this prospective cohort study. All patients with heart failure admission and reduced ejection fraction (EF ≤45%) were recruited. An in-hospital sleep study was ordered as part of standard heart failure orders, regardless of risk factors for SDB. Patients with previously diagnosed SDB or who were on treatment were included, but did not have an in-hospital sleep study. The primary outcome was post-discharge all-cause mortality, determined by national and state vital statistics databases.
A total of 4,847 patients were hospitalized during the specified period for heart failure (1,713 with preserved EF). After exclusions, refusal to consent and uninterruptable sleep results, 525 (47%) were diagnosed with obstructive sleep apnea (OSA), 344 (31%) with central sleep apnea (CSA) and 248 (22%) with no or minimal SDB (nmSDB). In-hospital deaths were also excluded from final analysis, but they included 21 patients: 6 CSA (2%), 12 OSA (2%), and 3 (1%) patients with nmSDB. The average age was 60.3 ± 14.7 years old, and there were more women in the nmSDB (44%) group compared to the CSA (18%) and OSA (27%) groups (p < 0.05). Median follow-up was 35.8 months. CSA was independently associated with mortality. The multivariable hazard ratio (HR) for time to death for CSA versus nmSDB was 1.61 (95% confidence interval [CI], 1.1-2.4; p = 0.02). OSA was also independently associated with mortality with a multivariable HR versus nmSDB of 1.53 (CI, 1.1-2.2; p = 0.02). These values were adjusted for multiple covariates, including EF, body mass index, renal function, diabetes, type of cardiomyopathy, and length of stay, among others listed in the text.
The authors concluded that newly diagnosed SDB during heart failure hospitalization is an independent predictor of post-discharge mortality.
Despite many advances in therapies, heart failure remains a huge economic burden. Identifying predictors of poor outcomes associated with heart failure may help target resources and therapies at reducing mortality and cost. Both OSA and CSA are common comorbid conditions found in patients with heart failure. The increased risk of post-discharge mortality in heart failure patients with SDB could not be explained by severity of heart failure or other baseline demographic characteristics. The difference in survival was even more impressive when comparing treated to untreated SDB. SDB is a potentially treatable predictor of poor outcome in heart failure patients, providing an opportunity to impact outcomes of patients admitted with heart failure and reduced EF.
Keywords: Heart Failure, Sleep, Sleep Apnea Syndromes, Sleep Apnea, Obstructive, Sleep Apnea, Central, Hospitalization, Cohort Studies, Risk Factors, Vital Statistics
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