Prevalence and Characteristics of Sleep Apnea in Patients With Heart Failure: A Single-Center Study

Introduction Heart failure is a common outcome of chronic cardiovascular diseases and carries a poor prognosis. Sleep apnea is an important comorbidity in heart failure patients, increasing the risk of mortality. Obstructive sleep apnea (OSA) is more commonly associated with heart failure with preserved ejection fraction, while central sleep apnea (CSA) prevalence increases with worsening New York Heart Association (NYHA) functional class and decreasing ejection fraction. The primary endpoint of the study is the prevalence of sleep apnea in heart failure patients. Secondary endpoints were the characteristics of sleep apnea in heart failure, the association between sleep apnea and heart failure severity, and the relationship between sleep apnea and symptoms. Methods This single-center, cross-sectional study was conducted in the Department of Pulmonary Medicine and Cardiology, SCB Medical College and Hospital, Cuttack, Odisha, from March 2023 to July 2024. Fifty consenting adult, stable heart failure patients were included. All patients were on appropriate pharmacological therapy, with no acute exacerbation or medication change for over 1 month. Exclusion criteria  Patients with NYHA class IV, resting hypoxia, history of myocardial infarction, unstable angina, cardiac surgery within the past 3 months, pregnancy, obstructive lung disease, or hypothyroidism were excluded from the study. Heart failure was diagnosed based on clinical signs and symptoms and the assessment of left ventricular function by 2D echocardiography. Overnight polysomnography was performed to diagnose and assess sleep apnea. Results Our study included 50 heart failure patients with a mean age of 54.84 years (±15.12) and a mean BMI of 27.36 kg/m² (±6.55). The cohort comprised 23 patients with heart failure with preserved ejection fraction, 8 with mildly reduced ejection fraction, and 19 with reduced ejection fraction. All patients experienced dyspnea, while 94% reported fatigue. Common comorbidities included hypertension (72%) and diabetes (44%). The mean apnea-hypopnea index (AHI) was 28.39 (±26.33), with an apnea index of 19.71 (±20.80) and hypopnea index of 8.48 (±13.87). Sleep apnea affected 86% of patients, with 68% having OSA and 18% having CSA. Female patients had a higher prevalence of sleep apnea (90.5%) than males (82.75%). Sleep apnea was common across all heart failure categories, with OSA predominant in each. Positive correlations were found between AHI and total sleep time below 90% oxygen saturation (TST90), while negative correlations were found between AHI and minimum SpO₂ during sleep. However, multivariate regression analysis revealed that BMI, left ventricular ejection fraction, age, and male gender were not independent risk factors for sleep apnea severity. Conclusion This study demonstrates a high prevalence of sleep apnea among stable heart failure patients, with OSA being the most common type. Sleep apnea was common across all heart failure categories, with a higher prevalence in female patients. The findings highlight the significant association between heart failure and sleep apnea, emphasizing the need for increased awareness and screening. The study's results have important implications for the diagnosis and treatment of sleep apnea in heart failure patients.