Presentation & Risk Factors

The presentation of OSA is very heterogeneous.

Presenting symptoms include: excessive sleepiness, fatigue, snoring, witnessed breathing cessation, sleep disruption and frequent awakenings, nocturia, disruption of concentration, memory and executive functions, depressed mood, or decreasing work performance. Common risk factors include male gender, age over 50 years, overweight and obesity, excess alcohol consumption, post-menopause (females). Lifestyle/weight loss advice is an important part of management. The prevalence of OSA is increased in patients with type 2 diabetes, those with hypertension and cardiovascular disease, and in patients prescribed sedative medications.

The clinical presentation of OSA is very heterogeneous ranging from those with loud snoring, frequent episodes of apnoea and excessive daytime sleepiness through to those who are asymptomatic. However more severe OSA is likely in those with risk factors and symptoms so it is important to consider OSA in obese patients who present with a history of daytime sleepiness, or tiredness, snoring and BMI > 30 kg/m². OSA needs to be distinguished from simple snoring which is the simplest form of sleep-disordered breathing.

Patients with positional OSA (the majority of apnoeas can be attributed to a supine sleep position) tend to be less obese, and to be younger than non-positional patients.¹

Approximately 30-50% of OSA patients report clinically significant insomnia symptoms, and approximately 30-40% of patients with insomnia fulfil diagnostic criteria for OSA.^{2, 3} The combination of OSA and insomnia results in greater morbidity, including daytime impairments (fatigue, concentration difficulties, reduced motivation), and depressive symptoms compared to patients with either OSA or insomnia alone.^{2, 4} The presence of insomnia symptoms in OSA patients reduces the acceptance and use of CPAP therapy. Recent RCT evidence has demonstrated that initial treatment with cognitive behavioural therapy for insomnia improves insomnia symptoms and may increase subsequent acceptance and use of CPAP therapy in patients with co-morbid OSA and insomnia.⁵ The Insomnia Severity Index is a simple self-report measure of insomnia severity; a score of ≥15 is indicative of clinically significant insomnia, which can be treated with cognitive behavioural therapy, even in the presence of OSA.^{6, 7}

OSA can also overlap with other sleep disorders including restless legs/ periodic limb movements that may disturb sleep and require adjunctive therapy.

History, physical examination, and questionnaires including the OSA50⁸, Epworth Sleepiness (ESS)⁹, STOP-Bang¹⁰ questionnaires, are best suited to establish complaints and comorbidity factors.

Table. Risk factors for OSA¹¹