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VOLUME 11 NUMBER 4 • NOVEMBER 2014
LEARNING FROM PRACTICE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
Obstructive sleep apnoea in diabetes: assessment and
awareness
IAN W SEETHO, SARAH V O’BRIEN, KEVIN J HARDY, JOHN PH WILDING
Correspondence to: Dr Ian Seetho
Department of Obesity & Endocrinology, Clinical Sciences Centre, University
Hospital Aintree, Longmoor Lane, Liverpool, UK
Tel: +44 (0)151 529 5885
e-mail:
iseetho@liv.ac.ukSarah V O’Brien, Kevin J Hardy
Department of Diabetes & Endocrinology, St Helens & Knowsley Hospitals
NHS Trust, UK
John PH Wilding
Department of Obesity & Endocrinology, University of Liverpool, UK
Previously published in
Br J Diabetes Vasc Dis
2014;
14
: 105–108
S Afr J Diabetes Vasc Dis
2014;
11
: 170–172
Table 1.
AHI for diagnosis and classification of OSA
3
Diagnosis
Events per hour
Normal
< 5
Mild OSA
5–15
Moderate OSA
15–30
Severe OSA
> 30
AHI = apnoea–hypopnoea index; OSA = obstructive sleep apnoea
Abstract
In 2008, the International Diabetes Federation (IDF) task force
on epidemiology and prevention released a consensus
statement recommending targeted screening for obstructive
sleep apnoea (OSA) in people with obesity and type 2
diabetes with classic OSA symptoms, and screening for
diabetes, hypertension and dyslipidaemia in those with OSA.
We conducted a survey to gain a greater understanding of
current practice in relation to the IDF recommendations for
the assessment of patients in diabetes clinics in the UK. An
online survey that was made accessible to diabetes healthcare
professionals with the support of the websites of several
diabetes organisations was performed. Most (approximately
two-thirds) of diabetes healthcare professionals who
responded to this survey were not aware of the IDF
recommendations either for diabetes screening in OSA
patients or for OSA assessment in type 2 diabetes and obesity.
Participants indicated that their local diabetes guidelines did
not incorporate assessment for OSA in those deemed to
be at risk. Furthermore, most participants perceived OSA
investigations to be primarily the domain of the respiratory
team rather than the diabetes team. The observations from
this survey provide a better understanding of the application
and impact of the IDF guidance in diabetes clinics.
Keywords:
diabetes, sleep disordered breathing, obesity, obstructive
sleep apnoea, sleep apnoea
Introduction
Changes in sleep breathing patterns termed SDB are associated with
obesity and/or type 2 diabetes. SDB is characterised by a spectrum
of altered sleep homeostasis that ranges from simple snoring to
obstructive sleep apnoea (OSA) with excessive daytime sleepiness. In
OSA, repeated apnoeas or hypopnoeas occur during sleep. An
apnoea is defined as the complete cessation of airflow for at least
10 seconds. A hypopnoea is defined as a reduction in air-flow that is
followed by an arousal from sleep or a decrease in oxyhaemoglobin
saturation.
1
Formal polysomnography counts the number of apnoeas
and hypopnoeas per hour during sleep and the AHI (frequency of
apnoea and/or hypopnoea) is used to diagnose and classify the
severity of OSA
2
(Table 1). The frequency of oxygen desaturation
episodes and severity of somnolence symptoms are also used.
4
The estimated prevalence of moderate to severe OSA is 13%
in men and 6% in women between 30 and 70 years.
5
The major
risk factors for OSA are obesity, gender and increasing age,
6
and
OSA is associated with a clustering of clinical cardiometabolic
manifestations including hypertension and type 2 diabetes. In OSA,
recurrent episodes of upper airway obstruction and changes in intra-
thoracic pressure result in recurrent periodic oxygen desaturations,
with frequent sleep arousals and fragmented sleep.
7,8
It has been estimated that up to 40% of OSA patients will have
diabetes,
9
and in patients with diabetes, the prevalence of OSA may
be up to 23%.
10
Prevalence estimates of OSA in severe obesity have
been reported to be 40–90%.
11
Patients may be unaware of the
association between OSA and type 2 diabetes. The symptoms and
signs of OSA may not be perceived relevant to their diabetes care,
therefore their OSA may remain unreported and undiagnosed.
The relationship of OSA with type 2 diabetes has important
implications for improving health outcomes, given the worldwide
prevalence of diabetes mellitus, predicted to increase from 8.3%
in 2013 to 10.1% in 2035 when patient numbers are expected to
reach 592 million.
12
Despite the absence of randomised controlled
trials (RCT) data supporting cardiovascular risk reduction with
continuous positive airway pressure (CPAP) treatment, we know that
cardiovascular disease risk is increased in OSA.
13
There is also evidence
that OSA may be associated with microvascular complications such
as diabetic retinopathy,
14
nephropathy
15
and neuropathy.
16
In 2008, the International Diabetes Federation (IDF) Taskforce on
Epidemiology and Prevention released a consensus statement that
recommended a targeted approach to screen individuals with type
2 diabetes and obesity for sleep-disordered breathing (SDB).
17,18
Briefly, the IDF recommended that healthcare professionals should
consider the possibility of OSA in patients with type 2 diabetes and
work in tandem with the local sleep service to provide a clinically
appropriate process of assessment, referral and intervention.
18
The purpose of this survey was to gain a greater understanding
of current practice in relation to the IDF recommendations for
assessment of OSA in patients attending diabetes clinics.