Adverse effects of obstructive sleep apnea (OSA), including sleep deprivation, can contribute to the progression of heart failure. The usual indication to diagnose and treat sleep apnea is subjective sleepiness. Previous studies suggest that patients with both heart failure and obstructive sleep apnea often do not complain of sleepiness, albeit their sleep time may be reduced. Therefore, we tested the hypothesis that patients with heart failure have less sleepiness and sleep less compared with subjects without heart failure for a given severity of OSA.
Sleepiness assessed with the Epworth Sleepiness Scale and sleep structure measured with polysomnography were compared among 155 consecutive patients with heart failure and from a random community sample (n = 1139) according to categories of the apnea-hypopnea index (<5, no OSA; 5-14, mild OSA; and ≥15, moderate to severe OSA).
Compared with the community sample, for any given severity of OSA, patients with heart failure had lower mean ± SE Epworth Sleepiness Scale scores (7.1 ± 0.4 vs 8.3 ± 0.2 [P = .005]; 6.7 ± 0.7 vs 9.2 ± 0.3 [P<.001]; and 7.8 ± 0.7 vs 9.8 ± 0.4 [P = .01]), indicating less sleepiness despite sleeping less (total sleep time mean ± SE [in minutes]: 306 ± 7 vs 384 ± 2, 295 ± 19 vs 384 ± 5, and 285 ± 13 vs 359 ± 7 for no, mild, and moderate to severe OSA, respectively; P<.001 for all comparisons).
Patients with heart failure have less subjective daytime sleepiness compared with individuals from a community sample, despite significantly reduced sleep time, whether or not they have OSA. In patients with heart failure, the absence of subjective sleepiness is not a reliable means of ruling out OSA.