All-Cause Mortality in People with Co-Occurring Insomnia Symptoms and Sleep Apnea: Analysis of the Wisconsin Sleep Cohort

Abstract

Purpose

Insomnia symptoms and sleep apnea frequently co-occur and are associated with worse sleep, daytime function, mental health and quality of life, compared to either insomnia or obstructive sleep apnea (OSA) alone. This study aimed to investigate the association of symptoms of co-morbid insomnia and sleep apnea (COMISA) with all-cause mortality.

Patients and Methods

Wisconsin Sleep Cohort data were analysed to assess potential associations between COMISA symptoms and all-cause mortality. Nocturnal insomnia symptoms were defined as difficulties initiating sleep, maintaining sleep, and/or early morning awakenings “often” or “almost always”, and/or regular sedative-hypnotic medicine use. OSA was defined as an apnea-hypopnea index ≥5/hr sleep. Participants were classified as having neither insomnia symptoms nor OSA, insomnia symptoms alone, OSA alone, or COMISA symptoms. Associations between the four groups and all-cause mortality over 20 years of follow-up were examined via multivariable adjusted Cox regression models.

Results

Among 1115 adult participants (mean ± SD age 55 ± 8 years, 53% males), 19.1% had COMISA symptoms. After controlling for sociodemographic and behavioral factors, COMISA symptoms were associated with an increased risk of all-cause mortality compared to no insomnia symptoms or OSA (HR [95% CI]; 1.71 [1.00–2.93]). OSA alone (0.91 [0.53, 1.57]) and insomnia symptoms alone (1.04 [0.55, 1.97]) were not associated with increased mortality risk.

Conclusion

Co-morbid insomnia symptoms and sleep apnea is associated with increased all-cause mortality risk. Future research should investigate mechanisms underpinning COMISA and the effectiveness of different treatment approaches to reduce mortality risk for this common condition.

Keywords:

• sleep disordered breathing
• Wisconsin Sleep Cohort
• COMISA
• obstructive
• sleep apnea
• insomnia
• respiratory

Acknowledgments

The authors gratefully acknowledge the prior work and open-data resources made available through the National Sleep Research Resources. The Wisconsin Sleep Cohort Study was supported by the US National Institutes of Health, National Heart, Lung, and Blood Institute (R01HL62252), National Institute on Aging (R01AG036838, R01AG058680), and the National Center for Research Resources (1UL1RR025011). The National Sleep Research Resource was supported by the US National Institutes of Health, National Heart Lung and Blood Institute (R24 HL114473, 75N92019R002). DJE is supported by a National Health and Medical Research Council of Australia (NHMRC) Senior Research Fellowship (1116942) and an Investigator Grant (1196261).

Author Contributions

All authors have contributed to the study design, data analysis and interpretation, and drafting of the manuscript. All authors have contributed and approved the final version of the manuscript. All authors agree to take responsibility and be accountable for the contents of the article.

Disclosure

Outside the submitted work, AS, RA, AV and NL have received research grant funding and equipment from ResMed and Philips Respironics. Outside the submitted work, PC and NL have received research funding from Defence Science and Technology and research grant funding and equipment from Philips Respironics. NL and HS have received research funding from Re-Timer Pty. Ltd. Outside the submitted work, DJE has a Collaborative Research Centre (CRC-P) Grant, a consortium grant between the Australian Government, Academia and Industry (Industry partner: Oventus Medical) and has research grants from Bayer, Apnimed, Invicta Medical and Takeda and serves on the Scientific Advisory Boards for Invicta Medical and Apnimed. None of the other authors have any relevant conflicts to declare. Outside the submitted work, ACR has received research funds from the Australian Sleep Health Foundation, Compumedics and consultancy fees from Sealy Australia.