GP Dr Roger Henderson offers advice on how to diagnose and manage obstructive sleep apnoea in adults
Obstructive sleep apnoea (OSA) is a relatively common condition and is estimated to affect 1.5 million adults in the UK.1 However, up to 85% of those affected are undiagnosed and untreated, despite treatment being relatively straightforward.In OSA, there is intermittent and repeated upper airway collapse during sleep, causing irregular breathing at night and excessive sleepiness during the day. The incidence of OSA is increasing as the incidence of obesity increases.2 Here are my ten top tips for GPs to consider in the assessment and management of OSA.
1. Remember there are several risk factors for OSA
Obesity is the strongest risk factor, but type 2 diabetes and related metabolic conditions such as insulin resistance and glucose intolerance also increase the risk for OSA.3,4 Other at-risk groups include: people with large neck sizes – more than 43cm (17in) for men and more than 40cm (16in) for women; middle-aged and older men; postmenopausal women; individuals with Down’s syndrome, hypothyroidism or acromegaly; smokers; those diagnosed with PCOS; and anyone with a family member with OSA.5 Obese children also have a higher prevalence and severity of OSA than children with a normal BMI.6
2. Take a careful history – including from a partner
If there is a history of snoring, witnessed apnoeic attacks when asleep and reported excessive daytime sleepiness, then always consider OSA as a diagnosis.7 NICE suggests a patient should be assessed for OSA if they report two or more of the following: snoring; witnessed apnoeic episodes; poor quality and unrefreshing sleep with unexplained excessive tiredness; choking during sleep; memory impairment; nocturia; and headaches on waking.8
3. Always consider an alternative diagnosis
There are multiple possible alternative diagnoses that can cause symptoms similar to OSA. These include insomnia, negative effects of shift work, and the use of drugs such as hypnotics, SSRIs, beta-blockers and the consumption of alcohol and stimulants such as caffeine. Restless leg syndrome can also cause daytime fatigue as can hypothyroidism, narcolepsy, Parkinson’s disease and depression.
4. OSA is associated with multiple significant harms
OSA is associated with increased risks of cardiovascular disease,hypertension, arrhythmias and stroke, independently of shared risk factors including obesity.9,10
OSA can also cause negative feedback, worsening co-existing conditions that may then in turn worsen the OSA (for example, it can cause hypertension which worsens the OSA).
OSA is also associated with an increased risk of road traffic accidents (one in four in the UK are linked to sleepiness), relationship problems (cohabiting partners often end up sleeping in separate bedrooms), sexual problems, fear of falling asleep on public transport and employment difficulties.11
5. Various management options can be tried ahead of referral
Always encourage the patient to reduce weight if they are obese or overweight, particularly if they have a large neck size. Refer them to a smoking cessation clinic if they smoke.8 If you think nasal congestion is a possible trigger, consider recommending the use of a steroid nasal spray and advise the patient to sleep with the head of their bed elevated. Check thyroid function levels and correct if abnormal. Ask the patient to stop drinking alcohol completely.11
6. Use objective questionnaires to assess OSA symptoms
The Epworth Sleepiness Scale (ESS) is a quick and easy scored questionnaire that can be used during a consultation to help assess daytime sleepiness, and guide referral.8 The total score is the sum of the answers given to eight questions relating to the likelihood of dozing off in different situations. Each question is scored from 0 to 3 (high chance of dozing off). A total score of 0-10 is considered normal, 11-14 mild daytime sleepiness, 15-18 moderate daytime sleepiness and 19-24 severe daytime sleepiness.11
It is advisable to refer patients for investigation if their ESS score is over 11. Patients should be referred urgently if their ESS score is above 18 or the patient has had a road traffic incident or near-miss event.
As not all patients with OSA experience daytime fatigue or sleepiness, it can also be helpful to use the STOP-Bang tool, a simple eight-question tool that includes questions on snoring and other risk factors like BMI, neck circumference and age, as well as sleepiness. Three or more ‘yes’ answers suggest a high risk of OSA; fewer than three ‘yes’ answers suggest a lower risk.13
7. A detailed referral letter can help clarify the diagnosis
If referring for investigation of OSA, the more information that can be provided in a referral letter, the more useful it is. Include the results of the person’s ESS score (and STOP-Bang if available), how sleepiness affects them, their BMI and any existing comorbidities. It is also helpful to include any occupational risk, oxygen saturation levels and any history of emergency admissions and acute non-invasive ventilation. Prioritise people for rapid assessment if they: have hypoxaemia (arterial oxygen saturation less than 94% on air) since daytime hypoxaemia can occur in people with OSA;14 if they are pregnant; or they have a vocational driving job or a job for which vigilance is critical for safety. (The DVLA rules for both drivers of cars and motorcycles [Group 1] and bus and lorry drivers [Group 2] state that in mild, moderate or severe OSA without excessive sleepiness a person may continue to drive as normal and there is no need to notify the DVLA. If there is excessive sleepiness where OSA is suspected the person must not drive until OSA has been diagnosed and a sleep clinic has confirmed that excessive sleepiness is being satisfactorily controlled by treatment.)15 They should also be prioritised if they have unstable cardiovascular disease or are undergoing preoperative assessment for major surgery.8
8. Overnight sleep studies remain the ‘gold standard’ investigation
Polysomnography (PSG) involves taking various physiological recordings overnight while the patient is asleep in a clinical setting. PSG includes the use of an electroencephalogram (EEG) to record brain activity, electro-oculograms (EOGs) to measure eye movements, and an electromyogram (EMG) to monitor muscle movement. At the end of a PSG, the number of apnoea-hypopnoea episodes while asleep is used to give the patient a score on the Apnoea-Hypopnoea Index (AHI). The AHI indicates the OSA severity and is calculated by adding up the number of apnoea-hypopnoea episodes while asleep and dividing them by the number of hours of sleep. An AHI score of between 5-14.9 per hour indicates mild OSA, 15-29.9 per hour moderate OSA, and 30 or more per hour severe OSA. If PSG availability is limited, then oximetry and more limited respiratory monitoring can be used for a diagnosis to be made.7
9. CPAP remains the best treatment for OSA
Most patients require lifelong therapy and continuous positive airway pressure (CPAP) needs to be worn for a minimum of four hours each night. However, patient compliance can be variable and if it is stopped, symptom recurrence typically occurs a few days later.7,16 A Cochrane review suggests there is currently insufficient evidence to recommend the use of drug therapy in the treatment of OSA, and the drug options solriamfetol and pitolisant hydrochloride are not recommended by NICE.17-19
10. Novel treatment options may benefit some patients
A number of patients have OSA which is either too mild to require CPAP or who find they are unable to tolerate this treatment. In such cases newer treatment options may be considered. These include an approach involving electrical stimulation of the hypoglossal nerve in moderate-to-severe OSA, which is now available on the NHS. A stimulator device is implanted under the patient’s chest skin with an electrode placed on the hypoglossal nerve that is activated during sleep. Studies suggest this is well-tolerated and produces a subjective improvement in quality of life and daytime sleepiness.20
There are now also App-based intraoral neuromuscular electrical stimulation devices, such as eXciteOSA, which are placed in the mouth for 20 minutes a day with the aim of strengthening tongue muscles in order to reduce mild OSA and snoring in adults. These devices have shown initial promise and are currently undergoing trials in the NHS.21
Dr Roger Henderson is a GP in south-west Scotland
References
1. British Lung Foundation. Obstructive Sleep Apnoea. Toolkit for commissioning and planning local NHS services in the UK. 2015
2. Jehan S, Zizi F, Pandi-Perumal S et al. Obstructive sleep apnea and obesity: implications for Public Health. Sleep Med Disord 2017;1(4):00019
3. Wolk R, Shamsuzzaman A, Somers V. Obesity, sleep apnoea and hypertension. Hypertension 2003; 42:1067-74
4. Moon K, Punjabi N, Aurora R. Obstructive sleep apnea and type 2 diabetes in older adults. Clin Geriatr Med 2015;31(1):139-47
5. American Academy of Sleep Medicine. Obstructive Sleep Apnoea. 2008
6. Su M, Zhang HL, Cai, X et al. Obesity in children with different risk factors for obstructive sleep apnea: a community-based study. Eur J Pediatr 2016;175(2):211-20
7. Greenstone M, Hack M. Obstructive sleep apnea. BMJ 2014;17;348:g3745
8. NICE. Obstructive sleep apnoea/hypopnoea syndrome and obesity hypoventilation syndrome in over 16s. 2021. NG202
9. Jean-Louis G, Zizi F, Brown D et al. Obstructive sleep apnea and cardiovascular disease: evidence and underlying mechanisms. Minerva Pneumol 2009;48(4):277-93
10. Hamilton G, Joosten S. Obstructive sleep apnoea and obesity. Aust Fam Physician 2017;46:460-3
11. Stradling J, Bates, G. Management of sleep apnoea and snoring – suggested guidelines for general practitioners and other interested medical professionals. Snorer.com
12. Asthma + Lung UK. Epworth Sleepiness Scale. 2022
13. British Snoring & Sleep Apnoea Association. STOP-Bang questionnaire. 2022
14. Fanfulla F, Grassi M, Taurino A et al. The relationship of daytime hypoxaemia and nocturnal hypoxia in obstructive sleep apnoea syndrome. Sleep 2008;31(2):249-55
15. Sleep Apnoea Trust. Detailed DVLA guidance for UK drivers with sleep apnoea. – updated Jul 2022.
16. Spicuzza L, Caruso D, Di Maria G. Obstructive sleep apnoea syndrome and its management. Ther Adv Chronic Dis 2015;6(5):273-85
17. Mason M, Welsh E, Smith I. Drug therapy for obstructive sleep apnoea in adults. Cochrane Database Syst Rev 2013;(5):CD003002
18. NICE. Solriamfetol for treating excessive daytime sleepiness caused by obstructive sleep apnoea. TA777. 2022
19. NICE. Pitolisant hydrochloride for treating excessive daytime sleepiness caused by obstructive sleep apnoea. TA776. 2022
20. Strollo P Jr, Soose R, Maurer J et al. Upper airway stimulation for obstructive sleep apnea. N Engl J Med 2014;370(2):139-49
21. Nokes B, Baptista P, Martinez-Ruiz de Apodaca P et al. Transoral awake state neuromuscular electrical stimulation therapy for mild obstructive sleep apnea. Sleep Breath 2022; published online 25 May
