Subjective Sleepiness And Activity Levels In Heart Failure Patients With Sleep Disordered Breathing

Abstract

Introduction: Heart failure (HF) patients with sleep disordered breathing (SDB) are no sleepier than those without SDB. We previously demonstrated that this may be due to reduced daytime activity (Hastings 2006). In this study we investigated the impact of age and HF on activity, since both may reduce activity, and consequently affect subjective sleepiness. Methods: Measures of sleep and activity were made in 3 groups; 25 HF patients with SDB (HF-SDB), 22 HF with no SDB (HF-noSDB) and 10 age matched healthy controls. SDB was measured using polysomnography and defined as an apnea hypopnoea index (AHI) >10/hour. Patients were classified as obstructive or central SDB based on the majority (>50%) of events. Activity was measured with wrist actigraphy for 14 days in 1 minute epochs Statistical analysis was carried out using the Kruskal-Wallis test, and Mann-Whitney U test with Bonferroni . adjustment. Results: Median (IQR) age was 68 (59-73) years; HF-SDB 70 (63-75), HF-noSDB 62 (54-70), controls 66 (64-69) years (p=0.845). 90% of participants were male. Left ventricular ejection fraction in the HF-SDB and HF-noSDB groups was 31% (19-40) and 35% (28-42) respectively. The AHI in the HF-SDB, HF-noSDB and control groups was 20.6 (13.5-38.0), 3.7 (2.5-5.9) and 2.2 (1.4-4.3) events/hour respectively. 18 of the 25 HF-SDB group had predominantly central sleep apnea. Body mass index did not differ between groups. Epworth sleepiness score was neither elevated nor significantly different between the HF-SDB group and the HF-no SDB group (8 (6-12) vs (7 (5-10) p=0.275); but was higher in the HF-noSDB than in the control group (7 (5-10) vs 4 (3-7) p=0.006). Further results are shown in the table. Table 1: Sleep, activity and diary results . Values given are median and IQR. NPSG-nocturnal polysomnography; TIB-time in bed; NS-not significant.