In a recent study published in American Heart Association Journalresearchers have identified gender-related patterns associated with the risk of cardiovascular outcomes in heart failure patients with central or obstructive sleep apnea.

study: Association between sex and cardiovascular disease in heart failure patients with obstructive or central sleep apnea syndrome. Image credit: Andrey Popov / Shutterstock.com

Heart failure and sleep apnea syndrome

Heart failure not only increases the likelihood of frequent hospitalization and death, but also carries a significant health and economic burden. Importantly, several other medical conditions associated with heart failure also affect patients’ quality of life.

For example, sleep apnea is experienced by more than 50% of heart failure patients. Most heart failure patients have obstructive sleep apnea or central sleep apnea, which is often not properly diagnosed or treated.

Although central sleep apnea is not prevalent in the general population, it has a high incidence in patients with heart failure. Comparatively, obstructive sleep apnea is not uncommon in the general population, with an incidence of 6-17%.

Obstructive sleep apnea is associated with specific gender-related patterns, with approximately 23.4% of women experiencing moderate to severe sleep apnea, but the incidence of this condition is is higher in men at 49.7%.

Obstructive sleep apnea also causes systemic inflammation, increased oxidative stress, hypertension, and increased left atrial and ventricular transmural pressure, increasing the risk of cardiac outcomes. However, gender differences in the risk of cardiac outcomes due to sleep apnea in cardiac patients remain unclear.

About research

Patients admitted to the hospital of the Chinese Academy of Medical Sciences with heart failure were included in the current study to examine the association between cardiovascular disease outcomes and different types of sleep apnea. All study participants were over the age of 18 and underwent a sleep study that included nocturnal sleep monitoring.

Echocardiographic findings and elevated levels of natriuretic peptides were used to define heart failure. The ejection fraction from the left ventricle was used to classify heart failure as heart failure with reduced, intermediate, or preserved ejection fraction.

Demographic information such as sex and gender, and vital measurements such as heart rate and blood pressure were obtained for all study participants. The electronic health record also provided detailed information on comorbidities.

Fasting blood samples were collected from all patients during hospitalization. These blood samples were used for a wide range of laboratory tests, including blood gas, blood chemistry, cardiac biomarker tests, glycosylated hemoglobin tests, liver function tests, and kidney function tests. Various cholesterol tests were also performed, including total cholesterol, high-density lipoprotein (HDL), and LDL cholesterol tests.

Overnight sleep monitoring was performed using a portable cardiopulmonary sleep monitoring device that records thoracic and abdominal movements, nasal airflow, heart rate, snoring episodes, and pulse oximetry. Study participants had follow-up visits every 3 months for up to 1 year after discharge and every 6 months thereafter.

Data on cardiovascular disease outcomes were obtained from telephone follow-up visits, clinical visit notes, and medical records. The primary outcome was unplanned hospitalization due to worsening heart failure or cardiovascular death.

research result

Although the prevalence of obstructive sleep apnea and central sleep apnea was not significantly different between men and women, cardiovascular outcomes such as readmission for heart failure were significantly lower than obstructive sleep apnea. It was higher in female heart failure patients with hourly apnea syndrome.

Obstructive sleep apnea syndrome was associated with increased incidence of primary outcomes in female heart failure patients, whereas central sleep apnea syndrome did not show these associations. The risk of cardiovascular disease associated with central sleep apnea was similar in male and female heart failure patients.

Obstructive sleep apnea was also associated with a higher risk of readmission for heart failure in female patients. In men with heart failure, obstructive sleep apnea was associated with an increased risk of cardiovascular death.

conclusion

Study results show that obstructive sleep apnea syndrome in patients with heart failure is associated with gender differences in cardiovascular disease risk. More specifically, female heart failure patients with obstructive sleep apnea had a higher risk of readmission than male patients.

Central sleep apnea syndrome was not associated with gender differences in cardiovascular disease outcomes. However, the incidence of readmission for heart failure was higher in female heart failure patients with sleep apnea. In comparison, male patients with sleep apnea had a higher incidence of cardiovascular death.