Research indicates that the mechanisms responsible for the development of obstructive sleep apnea (OSA) differ between patients. Denise M. O’Driscoll, PhD, and colleagues suspected OSA traits could differ between ethnicities as well, possibly posing challenges in diagnosis and treatment.

For a study published in Sleep, the researchers examined whether loop gain, arousal threshold, pharyngeal collapsibility, and muscle compensation differ between Chinese and Caucasian individuals with OSA. They used mathematical modelling techniques to determine how different traits contributed to the underlying pathophysiology of OSA in Chinese patients. Participants were compared by ethnicity and severity of OSA.

“We found that Chinese patients had significantly more collapsible upper airways (68.9 [51.5–75.2] vs. 74.0 [65.1–80.4] % veupnea, U = 703, p = 0.012) but a lower loop gain (0.60 [0.50–0.67] vs. 0.63 [0.57–0.81], U = 762, p = 0.043),” explains Dr. O’Driscoll. However, the researchers found no statistically significant differences in muscle compensation or arousal threshold between ethnicities. Further analysis indicated that pharyngeal collapsibility and loop gain traits helped explain the differences between Chinese and Caucasian patients. “Clinicians should take into consideration that OSA in their Chinese patients is likely to be driven by a small, collapsible upper airway, which may impact treatment pathways,” notes Dr. O’Driscoll.

The study results showed that obesity is not as reliable an indicator of severe OSA for Chinese patients as it is for Caucasian patients. Dr. O’Driscoll suggests screening Chinese patients for sleep-disordered breathing when presenting with complaints of daytime sleepiness. “Our study also suggests that the most effective treatments will likely be those that improve upper airway anatomical predisposition, for example oral appliances, weight loss, surgery, and positional therapy,” adds Dr. O’Driscoll.

This study team is continuing its research with a focus on clinical outcomes of treatment for Chinese patients with OSA. “These needs exist in any ethnic population where we can identify differences in OSA pathophysiology,” says Dr. O’Driscoll.