New Study Finds Ventilatory Burden to be a Key Predictor of Sleep Apnea Mortality
A recent study published in the American Journal of Respiratory and Critical Care Medicine has shed light on the importance of ventilatory burden (VB) as a predictor of mortality in patients with obstructive sleep apnea (OSA). This study aimed to address the limitations of the commonly used apnea-hypopnea index (AHI) in assessing the severity of OSA and its associated risks.
OSA is a chronic condition that is characterized by frequent pauses in breathing during sleep, leading to daytime sleepiness and potential cardiovascular consequences in the long term. The AHI, commonly used to diagnose OSA, only captures the frequency of respiratory events such as apneas and hypopneas. However, it fails to differentiate the ventilatory disturbances from the consequences of hypopneas. To overcome this limitation, researchers focused on developing a measure that could reliably identify the ventilatory load of OSA.
To investigate the relationship between VB and mortality in OSA patients, the researchers analyzed data from two large groups, the Sleep Heart Health Study (SHHS) and the Sao Paolo Epidemiological Study (EPISONO), as well as two retrospective clinical cohorts from the New York University Center for Brain Health and Relating Sleep Disordered Breathing to Daytime Function (DAYFUN). The study aimed to determine the association between VB and the extent of OSA, as well as its predictive value for cardiovascular and any-cause mortality.
The researchers utilized overnight airflow measurements obtained through various methods, such as nasal cannulas and pressure transducers, to calculate VB. They defined VB as the percentage of breaths during sleep with less than 50% amplitude. The results showed that VB exhibited a dose-response association with OSA severity and displayed low night-to-night variability. The therapeutic use of continuous positive airway pressure (CPAP) had a significant impact on reducing VB, indicating its potential as a treatment strategy.
The study findings revealed that VB was a significant predictor of cardiovascular and any-cause mortality among OSA patients, even after adjusting for other factors such as the automated hypoxic burden (HB). This suggests that VB could serve as a valuable tool for clinicians in managing the care of OSA patients, offering an alternative measure to assess the severity and mortality risks associated with the condition.
According to Dr. Ankit Parekh, the corresponding author of the study, this newly developed metric for assessing sleep apnea severity provides clinicians with a validated tool that overcomes the limitations of the AHI. The researchers have developed a software program that can be readily used by sleep labs, making it accessible to clinicians without requiring specialized expertise.
While further research is ongoing, this study offers promising insights into the predictive value of ventilatory burden in sleep apnea mortality. By providing clinicians with a more accurate and reliable measure of OSA severity, this metric could help inform treatment decisions and improve patient outcomes.
