Sleep on it | AMA (WA)


Woman stretching on bed after sleep

Sleep on it

Thursday May 1, 2014

By Dr Jack Philpott, Respiratory and Sleep Medicine specialist

The specialty of sleep medicine has evolved over the last decade, but it is vital to upskill and engage primary care physicians to manage the burden of sleep disorders.

Adequate restorative sleep, along with regular exercise and good diet, is a cornerstone of a healthy and productive life.

Insufficient sleep is a common problem in western societies. Insufficient sleep may result from voluntary restriction of sleep time or due to an underlying sleep disorder.

In 2010 the Sleep Heart Foundation commissioned a national survey conducted by telephone surveying 1512 adolescents and adults aged between 14 and 70 years of age. Fourteen questions were asked about sleep. Five questions were asked about sleeping difficulty, two about sleep apnoea and snoring, one each on restless legs and sleep medication, and three on daytime impairment. Two questions were specifically asked about sleep duration on the weekends and weekdays.

The results were as follows:

  • 20% of respondents described frequent difficulty initiating sleep
  • 35% reported frequent waking during the night
  • 35% reported waking unrefreshed
  • 24% reported inadequate sleep.
  • The daytime consequences of sleepiness, fatigue, exhaustion or irritability were reported by up to 24% of respondents
  • The overall estimated prevalence of severe insomnia was 6.9 per cent
  • Based on a history of frequent snoring and witnessed apnoea, the prevalence of sleep apnoea was estimated at 4.9%.

The estimated prevalence of Insomnia and OSA from this questionnaire closely matches the prevalence determined from previous reported population-based studies.

About 50 per cent of the reported sleep disturbance could be attributed to an underlying sleep disorder such as Insomnia or Obstructive Sleep Apnoea while the remaining 50 per cent was likely related to insufficient sleep through subject choice.

These results are similar to a recent study by the Centres for Disease Control which reported that 28 per cent of US adults had insufficient sleep or rest (less than seven hours a night) on most nights over a 30-day survey period.

The economic and social costs of sleep disorders (OSA and Insomnia), incorporating both direct healthcare costs and indirect financial cost (including loss of productivity and motor vehicle accidents) has been estimated at over $5 billion annually.

This economic analysis did not include the costs of volitional insufficient sleep or problems related to shift work (17 per cent of the adult working population are involved in shift work).

Obstructive Sleep Apnoea is highly prevalent.

In the early 1990s it was estimated that 24 per cent of middle-aged men and 9 per cent of women had evidence of OSA.

Recent data suggests a further increase in the prevalence of OSA likely related to the rising incidence of obesity and the ageing of the population.

A survey of 3007 participants conducted in South Australia in 2009 using a simple questionnaire and demographic measurements (STOP-BANG) highly predictive of the risk of moderate to severe sleep apnoea estimated that over half the surveyed males (57.1 per cent) and 19.3 per cent of the women were at high risk of sleep apnoea.

Despite the high prevalence of OSA, most patients are minimally symptomatic. Daytime somnolence is a poor predictor of the probability of clinically relevant disease.

OSA contributes to accelerated cognitive decline and mood disorders. It has been associated with an increased risk of type 2 diabetes, hypertension, cardiovascular disease and stroke.

There is an urgent need to develop models of care that cost-effectively treat patients who have clinically important disease (moderate to severe disease or milder disease with symptoms).

Models of care where a single index such as AHI is relied on solely in order to facilitate the sale of a CPAP machine can lead to excessive investigation, inappropriate treatment and patient disengagement in the therapeutic process.

Weight loss is a treatment strategy that should be encouraged for all severity levels of OSA. Although weight loss can result in a cure (AHI <5) in patients with mild sleep apnoea, a cure is rarely achievable either by surgical or non-surgical weight loss strategies in patients with moderate to severe apnoea.

Beyond weight loss and other lifestyle factors such as alcohol avoidance, treatment options can range from CPAP and mandibular advancement splints through to new surgical options.

In deciding upon a particular treatment modality, it is important to access the initial motivations of the patient for presenting, level of daytime symptoms, commitment to long-term treatment upper airway anatomy.

No matter the treatment modality recommended regular follow-up is important to ensure ongoing adherence with the therapy, particularly CPAP. Motivational techniques have been used by some groups to improve acceptance and long-term adherence with CPAP therapy.

Many patients present with more than one sleep disorder and insomnia has adverse effects on acceptance and tolerance of treatment but is responsive to treatment using cognitive behavioural therapy (CBT).

Prospective studies show OSA is a risk factor for insulin resistance, hypertension, cerebral vascular disease, ischaemic heart disease, cardiac arrhythmias including atrial fibrillation and heart failure.

Several large longitudinal studies have shown mortality risk of OSA which is prevented by CPAP. However, these studies were not randomised controlled trials and the outcomes of several large randomised controlled trials are currently underway and eagerly related. Data from these trials is expected as early as 2016.

The speciality of sleep medicine has evolved over the last decade and is now a dedicated training pathway through the Royal Australian College of Physicians. This has led to an increase in the number of available specialists.

However, given the large burden of disease including not only OSA but insomnia, shift work and other neurological sleep disorders, it will be vital to upskill and engage primary care physicians in the management of sleep disorders.

There are important health consequences of poor sleep for the individual and the community and it is important that the medical profession is not bypassed in the management of these important disorders.