Fewer Than 7 Hours of Sleep May Increase Mortality Risk In Patients with Sleep Apnea

Fewer than 7 hours of sleep each night may increase risk of all-cause mortality in individuals with obstructive sleep apnea (OSA), independent of apnea-hypopnea index (AHI), according to the investigators of a study that was recently published in JAMA Open Network. Although participants who got less sleep had higher risk of all-cause mortality, investigators note that more studies need to be done to understand the association.

“Sleep duration is the most important biomarker of sleep quantity and has effects on various systems,” the study authors wrote in the article. “Short sleep duration was reported to be associated with multiple cardiovascular and endocrine diseases as well as all-cause mortality in the general population.”

There are currently no concrete data to confirm an association between sleep duration and all-cause mortality among patients with OSA, as defined by the AHI. This study aimed to understand this association in those with OSA.

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Investigators evaluated data collected from 2574 participants who filled out a questionnaire and completed a polysomnography (PSG) study for the Sleep Heart Health Study (SHHS). Participants were enrolled between 1995 and 1998 and estimated follow-up was 11.8 years.

In the current study, investigators divided participants into 1 of 4 groups based on objective sleep duration: those who slept 7 or more hours per night, those who slept 6 to <7 hours per night, those who slept 5 to <6 hours per night, and those who slept <5 hours per night.

The results of the study showed an association between objective sleep duration and all-cause mortality. Participants who got 6 to <7 hours of sleep (hazard ratio [HR], 1.53 [95% CI, 1.13-2.07]), 5 to <6 hours (HR, 1.40 [95% CI, 1.03-1.90]), or <5 hours (HR, 1.64 [95% CI, 1.20-2.24]) of sleep had a higher risk of all-cause mortality than people who got >7 hours. These findings were independent of AHI, which serves as an assessment to determine OSA severity.

Although 30.6% of participants reported that their habitual (subjective) sleep duration was <7 hours, objective measurements showed that 86.7% of patients got <7 hours of sleep each night. However, subjective sleep duration was not associated with increased risk of all-cause mortality. Participants who got <5 hours or 5 to <6 hours of sleep per night did not have statistically significant worse risk of all-cause mortality than the other.

Investigators also conducted further research to understand the impact of airway pressure using continuous positive airway pressure (CPAP), although they found that it may not have a significant impact on mortality outcomes.

There are some limitations of this study, including a possible reduction in calculated objective sleep duration. In addition, this was a self-reported study, there might be selection bias, and there might be missing data related to CPAP treatment.

The effects of less sleep may be broad, the authors said.

“Short sleep duration in OSA was found to be significantly associated with hypertension history at baseline in our study,” the authors wrote in the article. “Short sleep duration was also reported to be associated with other adverse health outcomes in OSA, including altered insulin resistance and visceral obesity.”

More studies should be done to understand why shorter sleep might lead to these effects, and investigators should evaluate possible benefits associated with extending sleep length.

Reference

Lin Y, Wu Y, Lin Q, et al. Objective Sleep Duration and All-Cause Mortality Among People With Obstructive Sleep Apnea. JAMA Netw Open. 2023;6(12):e2346085. doi:10.1001/jamanetworkopen.2023.46085