Possible Association Found Between Untreated Sleep Apnea, Flu Hospitalization

Adults with obstructive sleep apnea (OSA) who are not adherent to continuous positive airway pressure (CPAP) therapy were found to be more likely to be hospitalized with influenza than those who used CPAP, according to study findings published in the Journal of Clinical Sleep Medicine.

For the approximately 30 million American adults with OSA, disruptions in sleep caused by the condition may adversely impact immune system functioning, note the researchers. Amid the coronavirus disease 2019 (COVID-19) pandemic, this can have an extensive impact on risk of infection and adverse outcomes among this patient population. Moreover, the emergence of the flu season may further exacerbate this risk, as patients with OSA may require hospitalization amid surging rates of COVID-19 infection.

One common treatment for OSA, CPAP therapy, has emerged as a viable solution that works by using mild air pressure to keep the airways open during sleep. The researchers sought to investigate whether patients with OSA who undergo CPAP therapy would be at a lesser risk of hospitalization due to influenza infection than nonadherent patients.

Deriving medical records of patients at Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, who had both OSA and a new, laboratory-confirmed influenza infection between 2016 and 2018 (N = 53), the study reviewed results of polysomnography, CPAP usage, influenza vaccination records, confirmation of influenza infection, and influenza-related hospitalizations and complications.

The researchers compared results of those adherent (n = 25; mean age, 60 years; 52% male) and nonadherent (n = 28; mean age, 63 years; 54% male) to CPAP therapy. Adherence was defined as usage of at least 4 hours per night for at least 70% of nights.

In comparing odds of hospitalization from influenza infections, patients conservatively treated without CPAP or nonadherent to CPAP therapy were at a nearly 5-times greater risk of hospitalization than those adherent to CPAP (odds ratio, 4.7; 95% CI, 1.3-19.5, P = .01).

After examining both groups for receiving the flu vaccine, the nonadherent CPAP patient group was found to be more likely (75%) to have been given the vaccine than the adherent group (56%), which the researchers say may be an indication of the negative impact that poor sleep has on vaccine responsiveness. However, the difference in vaccination was not statistically significant.

Overall, 61% (17 of 28) of patients not prescribed or nonadherent to CPAP therapy were hospitalized with the flu compared with 24% (6 of 25) of adherent patients. Although greater rates of hospitalization were observed, no higher odds of complications from influenza were seen among either group.

"These results would suggest that use of a treatment, CPAP, that improves sleep quality reduces the severity of influenza infection as determined by rate of hospitalization," said study author Glen Greenough, MD, associate professor of medicine, psychiatry, and neurology at the Dartmouth-Hitchcock Medical Center, in a statement. "This might suggest that treating sleep apnea and thereby improving sleep quality has a beneficial effect on the immune system. It also suggests that treating sleep apnea with CPAP could help reduce hospitalizations, thereby reducing health care costs."

Reference

Mok EM, Greenough G, Pollack CC. Untreated obstructive sleep apnea is associated with increased hospitalization from influenza infection. J Clin Sleep Med. Published online August 11, 2020. doi:10.5664/jcsm.8744