The risk of death is more than two times higher in older adults who have sleep apnea and report struggling with excessive daytime sleepiness, according to new research.
Results of adjusted proportional hazards modeling show that older adults with moderate to severe sleep apnea who reported struggling with excessive daytime sleepiness at baseline were more than twice as likely to die (hazard ratio = 2.28) as subjects who had neither problem. The risk of death was insignificant in older adults with only excessive daytime sleepiness (HR = 1.11) or sleep apnea (HR = 0.74). Participants had a mean age of 78 years at baseline, and about 55% (n = 160) died during an average follow-up period of 14 years.
“Excessive daytime sleepiness, when associated with sleep apnea, can significantly increase the risk of death in older adults,” said principal investigator and lead author Dr Nalaka S. Gooneratne, assistant professor of medicine in the University of Pennsylvania Health System in Philadelphia. “We did not find that being sleepy in and of itself was a risk. Instead, the risk of increased mortality only seemed to occur when sleep apnea was also present.”
Gooneratne added that both daytime sleepiness and sleep apnea are common problems, with sleep apnea affecting up to 20% of older adults.
The study, published in the journal Sleep, involved 289 adults with neither dementia nor depression who were recruited from the community; 74% were female. About half (n = 146) had significant levels of excessive daytime sleepiness at baseline, reporting that they felt sleepy or struggled to stay awake during the daytime at least three to four times a week. Sleep apnea was measured objectively by 1 night of polysomnography in a sleep lab. For analysis, participants were included in the sleep apnea group only if they had an apnea-hypopnea index of 20 or more breathing pauses per hour of sleep, which represents a moderate to severe level of sleep apnea.
Participants were recruited between 1993 and 1998. Survival status was determined by searching the Social Security Death Index, with follow-up ending September 1, 2009.
According to the authors, the mechanism by which sleep apnea and excessive daytime sleepiness increase the risk of death is unclear. They suspect that inflammation may be involved, which could increase the risk of other medical problems such as hypertension. It also remains to be seen if treatment reduces the risk of death.
“Future research is needed to assess whether treating the sleep apnea can reduce mortality,” said Gooneratne.