Prevalence and clinical characteristics of sleep-disordered breathing in patients with heart failure of different left ventricular ejection fractions

Purposes The prevalence of sleep-disordered breathing (SDB) is high in patients with heart failure (HF), while the prevalence of SDB in HF with different left ventricular ejection fractions (LVEF) has rarely been reported. We aimed to explore the prevalence and clinical characteristics of SDB in patients with HF having different LVEF. Methods Patients with stable HF were consecutively enrolled. All patients underwent portable overnight cardiorespiratory polygraphy and echocardiography. According to their LVEF, the patients were divided into the HFrEF (HF with reduced EF, EF <40%), HFmrEF (HF with mid-range EF, 40 <= EF < 50), and HFpEF groups (HF with preserved EF, EF >= 50%). The prevalence and clinical data of SDB among the 3 groups were then compared. Results A total of 252 patients, including 134 men, were enrolled in the study. The prevalence of SDB in patients with HF was 70%. Obstructive sleep apnea (OSA) was diagnosed in 48% and central sleep apnea (CSA) in 22%. The prevalence of SDB in the HFrEE, HFmrEF, and HFpEF groups was 86%, 86%, and 62%, respectively (P = 0.001). The prevalence of OSA among the 3 groups was 42%, 47%, and 49%, respectively (P = 0.708), while the prevalence of CSA among the 3 groups was 44%, 40%, and 13% (P < 0.001). Logistic regression analysis revealed that age and BMI were independent risk factors for OSA in patients with HF, while LVEF and smoking were independent risk factors for CSA in patients with HF. Correlational analyses revealed that LVEF was negatively correlated with apnea-hypopnea index (AHI) (r = -0.309, P < 0.001) and central apnea index (CAI) ( r = -0 .5 58 , P < 0.001), while there was no significant correlation with obstructive apnea index (OAI). The ROC curve revealed that LVEF could predict the occurrence of CSA and SDB, with AUC =0.683 (95%CI 0.600-0.767, P < 0.001) and AUC = 0.630 (95%CI 0.559-0.702, P = 0 .001) , but not of OSA. Conclusions SDB was highly common in HF, and the prevalence of SDB was different in HF with different LVEF, mainly due to the difference in cardiac functions. The prevalence and severity of SDB in HFrEF and HFmrEF were significantly higher than those in HFpEF, which was mainly related to the increase in CSA. When HFmrEF was similar to HFrEF in cardiac functions, the prevalence, type, and severity of SDB were similar between the two groups. Changes in LVEF had a significant impact on CAI, but not on OAI. LVEF can predict the occurrence of CSA and SDB to a certain extent.

Automated summary

This study investigated the prevalence and clinical characteristics of sleep-disordered breathing (SDB) in patients with heart failure (HF) with different left ventricular ejection fractions (LVEF). The results showed that SDB was common in HF, and the prevalence of SDB differed among patients with different LVEF, mainly due to differences in cardiac functions. The prevalence and severity of SDB were significantly higher in HF with reduced EF (HFrEF) and HF with mid-range EF (HFmrEF) compared to HF with preserved EF (HFpEF), primarily due to an increase in central sleep apnea (CSA). LVEF could predict the occurrence of CSA and SDB to a certain extent.