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12-14-2018 | Sleep apnea | Editorial | Article

Diabetes and obstructive sleep apnea syndrome: Double trouble

Author: John Wilding

Author bio | Disclosures

Obstructive sleep apnea is part of the spectrum of sleep-related breathing disorders that range from benign snoring to severe obesity hypoventilation syndrome. The association of abnormal sleep with daytime sleepiness is termed “obstructive sleep apnea syndrome” and is the main focus of this article.

Obstructive sleep apnea syndrome is very common and it is well recognized that it is associated with obesity; however, its strong relationship with diabetes is less well appreciated by clinicians, despite a report highlighting this from the International Diabetes Federation 10 years ago [1, 2].

Sleep apnea is part of the spectrum of sleep disordered breathing disorders.

Epidemiology of obstructive sleep apnea syndrome

Epidemiological studies have shown that obstructive sleep apnea syndrome:

  • affects between 6% and 13% of the adult population;
  • is more common in men than women; and
  • is common in those who are obese [3].

Obstructive sleep apnea syndrome causes daytime sleepiness, which significantly affects quality of life, work productivity, and increases the risk of accidents. Importantly, obstructive sleep apnea syndrome is also associated with an increased risk of metabolic syndrome and its consequences, which include ischemic heart disease and stroke, over and above the risks already associated with concomitant obesity.

Obstructive sleep apnea syndrome is also a risk factor for type 2 diabetes, with recent studies from Finland and the USA showing an increased risk of 1.5–2-fold [4,5]. A study from Oxford in the UK found that 23% of patients with diabetes had obstructive sleep apnea syndrome [6]; some other studies, for example LookAHEAD, have suggested an even higher prevalence of 80%, although this included people with less severe forms of obstructive sleep apnea, which may not all warrant treatment [7].

Why is obstructive sleep apnea associated with diabetes?

Potential mechanisms that might explain these associations include intermittent hypoxia and sleep fragmentation, which may:

  • increase sympathetic activity;
  • activate the hypothalamic–pituitary–adrenal axis; and
  • increase oxidative stress and trigger inflammatory responses.

Some studies have found that obstructive sleep apnea syndrome may also be more common in people with type 1 diabetes, even in those who are not obese [8]. The mechanisms involved here are not known, but could possibly be related to the development of autonomic neuropathy. Cross-sectional observational studies have also shown higher prevalence of microvascular complications of diabetes, in particular higher rates of retinopathy and neuropathy in patients with obstructive sleep apnea syndrome and type 2 diabetes [9, 10], and more recently with poor healing of foot ulcers [11].

How to identify possible obstructive sleep apnea syndrome in the diabetes clinic

The diagnosis of obstructive sleep apnea syndrome should be suspected in patients with diabetes who report excessive daytime sleepiness; this can be assessed in clinic using the Epworth Sleepiness Scale [12]. The STOP-BANG questionnaire, which includes blood pressure, neck circumference, and BMI as markers of risk, is also useful [10]. Those scoring above 10 on the Epworth Scale, or 3 or above on the STOP-BANG questionnaire, should be referred for a sleep study; this is usually done as an overnight study at home using portable equipment that records pulse oximetry, breathing (either with airflow or a chest band) and an electrocardiogram trace. The data will be assessed in the sleep lab, and the key output is the apnea-hypopnea index, calculated by dividing the number of apnea events by the number of hours of sleep.

The apnea-hypopnea index [13].
AHI <5
AHI 5–14 per hour
AHI 15–30 per hour
AHI >30 per hour
AHI=apnea-hypopnea index

Most guidelines recommend offering continuous positive airway pressure (CPAP) treatment to those with an apnea-hypopnea index of 15 or above who have evidence of daytime sleepiness [11].

Treatment of obstructive sleep apnea syndrome

Treatment of the symptoms of obstructive sleep apnea syndrome, especially daytime sleepiness, should include advice about adopting regular sleeping habits as much as possible. Those who are obese should be supported in efforts to lose weight, as weight loss can improve symptoms; this has been shown with dietary weight loss, the glucagon-like peptide-1 receptor agonist liraglutide at the approved dose for obesity (3 mg daily), and with bariatric surgery [14–16]. Most people with obstructive sleep apnea syndrome and daytime sleepiness will also be offered a trial of CPAP, which helps to maintain airway patency during sleep and prevents the intermittent hypoxia and subsequent arousals from sleep that result in daytime sleepiness. Other treatments that are less effective, but preferred by some, include airway splints and surgical approaches such as uvulopalatoplasty.

There is no question that CPAP is an effective intervention that improves sleep quality and thus reduces daytime sleepiness in people with obstructive sleep apnea syndrome. However, it has been more difficult to convincingly demonstrate metabolic benefits, despite the strong epidemiological associations, and uncontrolled observational studies suggesting benefit [17]. Randomized controlled trials using “sham” CPAP are generally of short duration for ethical reasons. Those that have been conducted have consistently shown small reductions in blood pressure, but no changes in glucose metabolism, markers of insulin resistance, or metabolic syndrome [18, 19].

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In summary, obstructive sleep apnea is commonly associated with type 2 diabetes and its presence appears to be associated with a higher risk of complications. Treatment includes weight loss and use of CPAP; the latter will be most effective at controlling symptoms of daytime sleepiness, but glucose control and other risk factors should be managed according to standard guidelines.

  1. Shaw JE, Punjabi NM, Wilding JP, Alberti KGMM, Zimmet PZ. Sleep-disordered breathing and type 2 diabetes: a report from the International Diabetes Federation Taskforce on Epidemiology and Prevention. Diabetes Res Clin Pract 2008; 81: 2–12.
  2. Seetho IW, Hardy KJ, Wilding JPH. Obstructive sleep apnoea in diabetes - assessment and awareness. Br J Diabetes Vasc Dis 2014; 14: 105–108.
  3. Peppard PE, Young T, Barnet JH et al. Increased prevalence of sleep-disordered breathing in adults. Am J Epidemiol 2013; 177: 1006–1014.
  4. Strausz S, Aki S. Havulinna, Tuomi T et al. Obstructive sleep apnoea and the risk for coronary heart disease and type 2 diabetes: a longitudinal population-based study in Finland. BMJ Open 2018; 8: e022752.
  5. Huang T, Lin BM, Stampfer MJ, Tworoger SS, Hu FB, Redline S. A population-based study of the bidirectional association between obstructive sleep apnea and type 2 diabetes in three prospective U.S. cohorts. Diabetes Care 2018; 41: 2111–2119.
  6. West SD, Nicoll DJ, Stradling JR. Prevalence of obstructive sleep apnoea in men with type 2 diabetes. Thorax 2006; 61: 945–950.
  7. Foster GD, Sanders MH, Millman R et al. Obstructive sleep apnea among obese patients with type 2 diabetes. Diabetes Care 2009; 32: 1017–1022.
  8. Borel AL, Benhamou PY, Baguet JP et al. [Sleep apnea syndrome is highly prevalent in patients with type 1 diabetes]. Diabetes Metab 2010; 36(Suppl 1): A32.
  9. West SD, Groves DC, Lipinski HJ et al. The prevalence of retinopathy in men with type 2 diabetes and obstructive sleep apnoea. Diabet Med 2010; 27: 423–430.
  10. Tahrani AA, Ali A, Raymonds NT et al. Obstructive sleep apnea and diabetic neuropathy a novel association in patients with type 2 diabetes. Am J Respir Crit Care Med 2012; 186: 434–441.
  11. Maltese G, Fountoulakis N, Drakatos P et al. Elevated obstructive sleep apnoea risk score is associated with poor healing of diabetic foot ulcers: a prospective cohort study. Diabet Med 2018; 35:1494–1498.
  12. Johns MW. Daytime sleepiness, snoring, and obstructive sleep apnea - The Epworth Sleepiness Scale. Chest 1993; 103: 30–36.
  13. Obstructive sleep apnoea syndrome. Available at [Accessed 10 December 2018].
  14. Blackman A, Foster GD, Zammit G et al. Effect of liraglutide 3.0 mg in individuals with obesity and moderate or severe obstructive sleep apnea: the SCALE Sleep Apnea randomized clinical trial. Int J Obes (Lond) 2016; 40:1310–1319.
  15. Peromaa-Haavisto P, Tuomilehto H, Kossi J et al. Obstructive sleep apnea: the effect of bariatric surgery after 12 months. A prospective multicenter trial. Sleep Med 2017; 35: 85–90.
  16. Chirinos JA, Gurubhagavatula I, Teff K et al. CPAP, weight loss, or both for obstructive sleep apnea. N Engl J Med 2014; 370: 2265–2275.
  17. Marin JM, Carrizo SJ, Vicente E, Agusti AGN. Long-term cardiovascular outcomes in men with obstructive sleep apnoea-hypopnoea with or without treatment with continuous positive airway pressure: an observational study. Lancet 2005; 365: 1046–1053.
  18. Coughlin SR, Mawdsley L, Mugarza JA, Wilding JPH, Calverley PMA. Cardiovascular and metabolic effects of CPAP in obese males with OSA. Eur Respir J 2007; 29: 720–727.
  19. West SD, Nicoll DJ, Wallace TM, Matthews DR, Stradling JR. Effect of CPAP on insulin resistance and HbA1c in men with obstructive sleep apnoea and type 2 diabetes. Thorax 2007; 62: 969–974.

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