Sleep Apnea Worsens Acute HF Outcomes; Testing for It at HF Admission Proposed

October 04, 2013

ORLANDO, FL — Sleep-disordered breathing (SDB) identified during acute decompensated heart failure (ADHF) hospitalization, especially central sleep apnea (CSA), predicted elevated cardiac readmission risk at three and six months and a two-thirds increase in mortality at three years in a prospective cohort study[1,2].

Its authors propose that routine screening and treatment for central or obstructive sleep apnea (OSA) in hospitalized heart-failure patients might be a useful strategy for bringing down ADHF readmission rates and associated late mortality.

Sleep-disordered breathing is one of the most common heart-failure comorbidities, identified in >70% of patients admitted with ADHF, the study's senior author Dr Rami N Khayat (Ohio State University, Columbus) told heartwire here at the Heart Failure Society of America 2013 Scientific Meeting . Although sleep studies aren't typically performed after admissions for HF, he recommends that they be routinely included for patients without a prior diagnosis of SDB "early on in the hospitalization."

Khayat presented the single-center study of 1117 patients admitted for ADHF from 2007 to 2010 with lead author Angela Sow (Ohio State University). All had an LVEF <45% and had never been diagnosed with SDB. Their sleep studies conducted on the second night of admission used type 3 monitors (with a minimum of four physiologic monitoring channels). SDB was defined as an apnea-hypopnea index of >15 events per hour (usually considered moderate apnea).

Features of 1117 Patients With Central or Obstructive Sleep Apnea or No Sleep Disordered Breathing

End points CSA, n=344 OSA, n=525 No SDB, n=248 p
Age (y) 60.3 60.3 54.6 <0.05 vs CSA and OSA
LVEF (%) 23.1 26.3 29.5 <0.05 vs CSA and OSA
BMI 29.4 31.7 29.0 <0.05 vs OSA
LOS (d) 9.5 9.0 7.2 <0.05 vs CSA and OSA

CSA=Central sleep apnea
OSA=obstructive sleep apnea
SDB=sleep disordered breathing
BMI=body-mass index
LOS=hospital length of stay

CSA and OSA showed comparable significant, independent effects on late mortality. Both were independent predictors of six-month cardiac readmission, the risk doubling for CSA, in particular. CSA was an independent predictor of cardiac readmission at one, three, and six months.

Hazard Ratio (95% CI) for Mortality and Rate Ratio (95% CI) for Cardiac Readmission in 1117 Patients With CSA, OSA, or No SDB

Outcome CSA vs No SDB CSA vs OSA OSA vs No SDB
36-mo mortality 1.71 (1.2–2.5), p=0.007 1.03 (0.8–1.3), p=0.81 1.66 (1.1–2.4), p=0.007
1-mo cardiac readmission 1.92 (1.2–3.1), p=0.009 1.29 (0.9–1.8), p=0.14 1.48 (0.9–2.3), p=0.10
3-mo cardiac readmission 1.66 (1.2–2.4), p=0.005 1.33 (1.0–1.7), p=0.03 1.25 (0.9–1.7), p=0.20
6-mo cardiac readmission 1.97 (1.4–2.7), p<0.001 1.42 (1.1–1.8), p=0.004 1.39 (1.0–1.9), p=0.03

Adjusted for age, sex, LVEF, BMI, creatinine, diabetes, type of cardiomyopathy, CAD, chronic kidney disease, discharge SBP <110, hypertension, discharge ACE inhibitors or angiotensin-receptor blocker, discharge beta-blocker, index length of stay, admission Na and hemoglobin.

Khayat acknowledged that SDB in many patients could represent a facet of the acute heart-failure syndrome, rather than a distinct disorder; he said if so, it remains an independent measure of worsened HF "not explained away by LVEF, LV end-diastolic dimensions, natriuretic peptides, or anything else."

He added, "We've done validation studies on a similar [cohort, suggesting that] sleep-disordered breathing doesn't go away or change much after they're discharged."

Neither Khayat nor Sow had disclosures; Khayat has elsewhere disclosed previously consulting for Respicardia and receiving research grants from Respironics.

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