Sleep Apnea Signals Poor Survival in Hospitalized HF Patients

Marlene Busko

February 11, 2015

COLUMBUS, OH — In a large study of patients who were hospitalized for HF, those who were newly diagnosed with sleep-disordered breathing (sleep apnea) were more likely to die within a few years compared with their peers[1].

Specifically, the hazard ratio for all-cause mortality within 3 years of hospital discharge was 1.57 (95% CI 1.1–2.2; P=0.01) for HF patients with sleep apnea, after adjustment for multiple variables, in this study by Dr Rami Khayat (Ohio State University, Columbus) and colleagues, published online January 29, 2015 in the European Heart Journal. Preliminary results had been presented at a meeting in 2013 and covered by heartwire at the time.

In a smaller previous study[2], the researchers reported that newly discovered sleep apnea in HF patients was an independent predictor of hospital readmission. Taken together, the two studies highlight the need for greater screening for sleep apnea in HF patients, they say. "The independent mortality effect of sleep-disordered breathing, along with the previously demonstrated effect on readmissions, provide justification for routine screening for sleep-disordered breathing during acute heart-failure hospitalizations," they conclude.

Sleep-apnea treatment may improve HF outcomes, and patients who received adequate sleep-apnea treatment appeared to have better short-term survival, but this observational study was not designed to address this, they caution.

Invited to comment, Dr Virend K Somers (Mayo Clinic, Rochester, MN) told heartwire that the take-away message is that "cardiologists need to be aware of the high prevalence of sleep apnea in patients hospitalized with heart failure, and it would be important to look for sleep apnea" in these patients. However, "whether treatment will prevent death or prevent readmission remains to be addressed . . . in a randomized controlled trial," he added, echoing the researchers.

Is Sleep Apnea a Potentially Treatable Risk Marker in HF?

The researchers performed cardiorespiratory polygraphy on 1117 patients who were hospitalized for heart failure with LVEF <45% in a single center. "The use of cardiorespiratory polygraphy instead of polysomnography . . . is critical for providing a practical and generalizable method of case finding in this high-risk population and setting," they write.

The screening test detected sleep apnea in 78% of the HF patients: 344 patients (31%) had central sleep apnea and 525 patients (47%) had obstructive sleep apnea.

It is important to distinguish between the two types of apnea, since treatment is usually different, according to Somers. In obstructive sleep apnea, the airway collapses on inspiration, whereas in central apnea, patients lose the drive to breathe. "The treatment for obstructive apnea is often continuous positive airway pressure [CPAP], whereas for central sleep apnea, CPAP is often not effective and you need to use adaptive servoventilation," he said.

Compared with the patients without sleep apnea, those with sleep apnea were older (mean age of 60 vs 55) and more likely to be male (77% vs 56%).

Of the 1096 patients in the current study who survived until hospital discharge, 110 patients with central sleep apnea (34%), 153 patients with obstructive sleep apnea (32%), and 40 patients without sleep apnea (17%) died within 3 years, mostly from congestive HF.

Sleep apnea independently predicted the risk of death during follow-up.

Adjusted Hazard Ratios* For Time to Death During 36 Months After Hospital Discharge

Sleep apnea type HR (95% CI) P
Central 1.61 (1.1–2.4) 0.02
Obstructive 1.53 (1.1–2.2) 0.02
*Adjusted for LVEF; age; BMI; sex; race; creatinine; diabetes; cardiomyopathy type; CAD; chronic kidney disease; discharge systolic BP; hypertension; discharge ACE inhibitor or angiotensin-receptor blocker, discharge beta-blocker; initial length of hospital stay; admission Na; admission hemoglobin; and BUN

In the first year after being discharged from the hospital, 58 patients with central sleep apnea and 103 patients with obstructive sleep apnea completed CPAP therapy as recommended: they used the device for more than 4 hours a night for 6 to 12 months. These patients had a survival that was comparable to that of patients who did not have sleep-disordered breathing.

Thus, "sleep-disordered breathing is potentially treatable and may provide an opportunity to impact the outcome of HF hospitalizations," Khayat and colleagues write. The group is currently evaluating the effect of sleep-apnea treatment in patients with HF in a randomized controlled trial.

This research was supported by grants from National Institute of Health and the National Center for Research Resources . The authors and Somers have reported they have no relevant financial relationships.

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