Sleep Apnoea is a common sleep-related breathing disorder, causing pauses in breathing during sleep. There are different types of Sleep Apnoea, including Obstructive Sleep Apnoea (OSA), Central Sleep Apnoea (CSA) and Mixed Sleep Apnoea. However, OSA is the most prevalent type, affecting an estimated 1.5 million adults in the UK alone, with up to 85% of the affected patients being undiagnosed (1).

OSA is caused by an obstruction of the upper airway during sleep, leading to recurrent collapse of the pharyngeal space (2). This results in either partial blockage (hypopnoea) or complete obstruction (apnoea). The resulting combination of intermittent hypoxia, increased airway resistance and CO₂ changes result in sleep fragmentation. This leads to reduced slow-wave sleep and less time in REM sleep. Sleep fragmentation can further lead to both reduced sleep quantity and quality of sleep.

Patients with OSA may have low levels of consciousness at night (3), and diagnosis is often made upon observation by others, or patient's complaints of daytime fatigue and tiredness. OSA is associated with many problems, including affecting memory, daytime vigilance, causing morning headaches and excessive daytime sleepiness, and it is linked with increased cardiovascular risks (4).

Factors associated with OSA include certain a) anatomical features (1), including a large neck circumference, a set-back lower jaw, enlarged tonsils, macroglossia, and abnormal shapes of the upper airway, b) obesity (1–3), c) gender, with men being more affected than women, and d) age (1, 2, 5). A low arousal threshold, reduced neuromuscular tone and complete the approach toward characterisation of physiological traits in OSA (6).

OSA can cause excessive daytime sleepiness (EDS), independent of severity of the syndrome, impacting an individual's concentration during work and activities of daily life. It also has a substantial effect on memory as unfragmented sleep is essential for the development and consolidation of semantic memory (7). In addition, depression is a common symptom in untreated OSA (8).

Furthermore, those with untreated OSA are at an increased risk of having a motor vehicle accident (8), so those with job roles involving driving, e.g., professional drivers, are at particular risk if they suffer from undiagnosed OSA. The current estimate for the prevalence of OSA in HGV drivers is over 15% (1). Similar caution should be taken toward untreated OSA when handling heavy machinery or undertaking manual labour tasks that could put the patient of others at risk.

Untreated OSA increases the risk of cardiac conditions, particularly in moderate-severe disease, such as hypertension and heart disease. The recurrent apnoeas and hypopnoeas result in intermittent hypoxia, thus increased the sympathetic tone and the cardiac output. As a consequence, both the heart rate and the blood pressure increase, which can contribute to hypertension and increased cardiac stress (9). Cardiovascular disease accounts for 42% of deaths in people with OSA, compared to 26% in people without the condition (1).

It is estimated that up to 70% of those with type 2 diabetes have a form of sleep-disordered breathing (1), although it is possible that this is due to the close features of similar phenotypes leading to OSA and diabetes via the joint factor of obesity.

There are classic symptoms that patients suffering from OSA present with, such as snoring, fragmented sleep due to choking or gasping episodes, witnessed apnoeas or hypopnoeas by the partner, family or friends, and EDS, as measured by the Epworth Sleepiness Scale (10). Therefore, if the history is indicative of OSA and the patient has notable risk factors, the clinician should carry out further tests to confirm the diagnosis (11).

These include a) a physical exam to look for contributing factors or conditions, including an oral inspection, and the measurement of height, weight and neck circumference, b) blood tests, including a full blood count, thyroidal function tests, iron levels/ferritin and HbA1c, and c) considering to undertake a sleep study. For the latter, home- vs. inpatient sleep studies and level of quality (pulse oximetry, limited channel respiratory polygraphy, or polysomnography) should be discussed with the patient and chosen according to appropriateness (12).

The results of an overnight monitoring are then analysed to calculate the Apnoea Hypopnea Index (AHI), or in the case of a pulse oximetry the Oxygen Desaturation Index (ODI). These indices measure the number of episodes (of paused breathing) an individual experiences while asleep. These indices are also used to classify the severity of the OSA:

The advent of CPAP therapy in the 1980's provided a highly efficient treatment for patients with OSA (14) and triggered the opening of many clinical sleep services. However, long-term adherence to CPAP therapy is limited, with studies using “big data” reporting about 75% at 3-months (15, 16) It is therefore time to re-think a widely practised “one-size-fits-all” approach. The recently published NICE guidelines on OSA (17) have shifted the focus on the use of Mandibular Advancement Devices (MAD), while the recent European Respiratory Society (ERS) guidelines on non-CPAP therapy (18) mention further therapeutic choices and promote future research to develop the existing evidence base. The wider involvement of different specialties would favour “patient's choice.”

CPAP is a highly effective therapy to treat OSA and the best available first line treatment. However, patients with OSA require review of their compliance and adherence. In recent analyses of “big data” on a sample of 2.6 mio US citizen the 90-day adherence rate, as defined by >4 h usage of CPAP for more than 70% of the night, was 75% (15). In another sample, the data of about 800,000 patients suggested an age and gender dependant effect on 90-day adherence, ranging from about 51.3–80.6%, with an average adherence of 72.6% (16), and following patients at 1-year and longer sees CPAP adherence rates significantly drop further (40). Whatever the adherence rates in other sleep services, about one in four patients does not receive sufficient treatment at 3-months, and over time the proportion of untreated patients is growing.

It is therefore important to consider, establish and develop additional options for non-CPAP therapy to have the choice with the patient, improve adherence and long-term motivation, as significant numbers of patients will otherwise not be sufficiently treated by CPAP. Highly-frequented CPAP services need to consider what therapeutic options they can offer to those who do not use CPAP in the long-term. Bringing together a multidisciplinary team of respiratory physicians and CPAP technologists with dietitians, bariatric services, ENT departments, dentists, maxillofacial surgery and clinical trials units to offer a spectrum of non-CPAP services is essential (Figure 2). In addition, it is important to consider collaborations with the obstetrics department, as pregnant women are also at increased risk of developing OSA. Access to primary airway therapy for pregnant women could help to avoid ill health and adverse outcomes (e.g., pre-eclampsia). Finally, treatment targets for OSA in paediatric cohorts may be more focused on the adenotonsillectomy.

The development of a more structured and systematic approach toward the “difficult-to-treat” patient with OSA, someone who has failed primary airway therapy, is to embed case discussions within a clinical governance framework of a multidisciplinary team (Figure 2). Such an approach should involve all relevant specialties, with clinicians and physiologists involved in the delivery of the sleep service. Under audit conditions, this approach facilitates the prospective provision of evidence-based treatments and the optimal delivery of alternative treatment pathways for patients in whom the first line therapy was unsuccessful. A multidisciplinary approach is standard in most other chronic conditions of non-communicable diseases and there is evidence that team decisions together with the patients provide better outcomes and more individualised care than leaving the decision to individuals.

Treatment of OSA is moving toward a more bespoke approach, involving the patient and managing long-term ill health. This, however, implies a move away from a “one-size-fits-all” approach. In selected cases, this may mean that non-CPAP therapy may be a better long-term solution to control symptoms and cardiovascular risks than CPAP therapy, despite its proven safety and efficacy. The recent reviews of the evidence by NICE and the new ERS guidelines provide an opportunity to investigate the development of innovative treatment pathways. Systematic observation of clinically relevant outcomes and the follow-up of patients on non-CPAP treatments remains essential. Clinicians need to reassure patients who fail first line therapy in that they are not discharged from clinical services once established treatments has been trialled unsuccessfully. Symptom control is important for patient-centric care and many long-term problems in the management of OSA can be addressed with more tailored solutions, and having the choice of several non-CPAP treatments can make a big difference in the individual case where standard care has not offered successful resolution.

All authors have equally contributed to the idea, drafting, and final corrections of this manuscript.

JS is named inventor on a patent held by Guy's and St Thomas' NHS Foundation Trust and King's College London for an apparatus using electrical stimulation to treat OSA (WO2016124739A1). The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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