Sleep Apnea Has Many Faces

Douglas S. Paauw, MD

October 20, 2021

I recently saw a 62-year-old patient who had been struggling in her job at a law firm. She had been one of the top paralegals for over a decade, but recently had received a poor job performance. She told me she was forgetting things and was worried she might be developing dementia. Fortunately her problem stemmed from sleep apnea, and resolved with continuous positive airway pressure (CPAP) therapy.

Dr Douglas Paauw

Wallace and Bucks performed a meta analysis of 42 studies of memory in patients with sleep apnea and found sleep apnea patients were impaired when compared to healthy controls on verbal episodic memory (immediate recall, delayed recall, learning, and recognition) and visuospatial episodic memory (immediate and delayed recall).1 A meta-analysis by Olaithe and associates found an improvement in executive function in patients with sleep apnea who were treated with CPAP.2 I think this is worth considering especially in your patients who have subjective memory disturbances and do not appear to have a mild cognitive impairment or dementia.

About 15 years ago I saw a 74-year-old man for nocturia. He had seen two urologists and had a transurethral resection of the prostate (TURP) without any real change in his nocturia. I trialed him on all sorts of medications, and he seemed to improve temporarily a little on trazodone (went from seven episodes a night to four).

Eventually, after several years, I sent him for a sleep study. He had severe sleep apnea (-Apnea Hypopnea Index, 65; O2 saturations as low as 60%). With treatment, his nocturia resolved. He went from seven episodes to two each night.

Zhou and colleagues performed a meta-analysis of 13 studies looking at the association of sleep apnea with nocturia.3 They found that men with sleep apnea have a high incidence of nocturia.

Miyazato and colleagues looked at the effect of CPAP treatment on nighttime urine production in patients with obstructive sleep apnea.4 In this small study of 40 patients, mean nighttime voiding episodes decreased from 2.1 to 1.2 (P < .01).

I have seen several patients with night sweats who ended up having sleep apnea. These patients have had a resolution of their night sweats with sleep apnea treatment.

Arnardottir and colleagues found that obstructive sleep apnea was associated with frequent nocturnal sweating.5 They found that 31% of men and 33% of women with OSA had nocturnal sweating, compared with about 10% of the general population.

When the OSA patients were treated with positive airway pressure, the prevalence of nocturnal sweating decreased to 11.5%, which is similar to general population numbers. Given how common both sleep apnea and night sweats are, this is an important consideration as you evaluate night sweats.

I have seen many patients who have had atrial fibrillation and sleep apnea. Shapira-Daniels and colleagues did a prospective study of 188 patients with atrial fibrillation without a history of sleep apnea who were referred for ablation.6 All patients had home sleep studies, and testing was consistent with sleep apnea in 82% of patients.

Kanagala and associates found that patients with untreated sleep apnea had a greater chance of recurrent atrial fibrillation after cardioversion.7 Recurrence of atrial fibrillation at 12 months was 82% in untreated OSA patients, higher than the 42% recurrence in the treated OSA group (P = .013) and the 53% recurrence in control patients.

I think sleep apnea evaluation should be strongly considered in patients with atrial fibrillation and should be done before referral for ablations.

Pearl: Consider sleep apnea as a possible cause of or contributing factor to the common primary care problems of cognitive concerns, nocturia, night sweats, and atrial fibrillation.

Paauw is professor of medicine in the division of general internal medicine at the University of Washington, Seattle, and serves as 3rd-year medical student clerkship director at the University of Washington. He is a member of the editorial advisory board of Internal Medicine News. Paauw has no conflicts to disclose. Contact him at


1. Wallace A and Bucks RS. Memory and obstructive sleep apnea: a meta-analysis. Sleep. 2013;36(2):203. Epub 2013 Feb 1.

2. Olaithe M and Bucks RS. Executive dysfunction in OSA before and after treatment: a meta-analysis. Sleep. 2013;36(9):1297. Epub 2013 Sep 1.

3. Zhou J et al. Association between obstructive sleep apnea syndrome and nocturia: a meta-analysis. Sleep Breath. 2020 Dec;24(4):1293-8.

4. Miyauchi Y et al. Effect of the continuous positive airway pressure on the nocturnal urine volume or night-time frequency in patients with obstructive sleep apnea syndrome. Urology 2015;85:333.

5. Arnardottir ES et al. Nocturnal sweating–a common symptom of obstructive sleep apnoea: the Icelandic sleep apnoea cohort. BMJ Open. 2013 May 14;3(5):e002795. BMJ Open 2013;3:e002795

6. Shapira-Daniels A et al. Prevalence of undiagnosed sleep apnea in patients with atrial fibrillation and its impact on therapy. JACC Clin Electrophysiol. 2020;6(12):1499. Epub 2020 Aug 12.

7. Kanagala R et al. Obstructive sleep apnea and the recurrence of atrial fibrillation. Circulation. 2003;107(20):2589. Epub 2003 May 12.

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