Key:

NZ:           Nahida Zaman

ST:            Dr Shahrad Taheri

NZ:               Dr Shahrad Taheri is Senior Lecturer in Medicine, Diabetes and Endocrinology at the University of Birmingham, United Kingdom.  Hello and a very warm welcome to Optimal Clinical Diabetes Radio.  Dr Taheri can you tell us about the focus of your research at the University of Birmingham?

ST:                My research is interested in how sleep interacts with metabolism.  I have a particular interest also in obesity and putting the picture altogether, obstructive sleep apnoea is a key factor involving obesity and diabetes so I am interested in looking at how obstructive sleep apnoea affects health and particularly metabolic health.

NZ:               One of the highlights from the seventh national conference of the Primary Care Diabetes Society was a lecture you gave.  Your presentation addressed sleep apnoea.  Can you please tell our listeners about this particular presentation?

ST:                Sleep apnoea is actually a very common disorder.  If you look at the general population, about 4% of the general population will have sleep apnoea and basically what happens when you go to sleep is your muscles relax and so do your airway muscles so you are vulnerable in blocking your airway so what happens with obstructive sleep apnoea is the airway gets blocked hundreds and hundreds of times a night and what it does is basically because of their air flow, very little oxygen gets into the circulation so people develop what we call hypoxia which is low blood oxygen and because of that people wake up hundreds and hundreds of times without realising it.  The low oxygen also is a kind of stress so blood pressure goes up, there is increase in hormones that are related to stress but also because people do not sleep at night they are sleepy during the day so they are at increased risk of having car accidents and work accidents and things like that.  In the diabetes population it appears that obstructive apnoea is more common than the general population and depending on the study it ranges from about 20% to 80% of patients with diabetes.  Type II diabetes (patients) will have obstructive sleep apnoea.

NZ:               Dr Taheri just how serious is sleep apnoea in patients with diabetes?

ST:                Anybody who has got obstructive sleep apnoea is a high risk of stroke and cardiovascular disease so any diabetes patient who has got obstructive sleep apnoea is at high risk of those effects of sleep apnoea.  Additionally there is data just emerging that sleep apnoea can also affect diabetes control.  Now this means that if you treat sleep apnoea then you might be able to improve patients’ sugar control as well.

NZ:               What percentage of patients with diabetes have sleep apnoea?

ST:                It ranges between different studies so depending on where the study was carried out and what the population was it ranges from 20% to 80% but the problem with some of these studies is that they maybe suffer from what we call selection biases in that they choose the patients who they think have got sleep apnoea and for this reason the levels may be over-inflated but generally I would say around 30% to 40% will have sleep apnoea in a type II diabetes population.

NZ:               Sleep apnoea is regarded as an early warning that diabetes development is underway, why is that?

ST:                Sleep apnoea is a constellation of problems that goes with obesity so anybody who has got obesity is at high risk of sleep apnoea and diabetes and if you look at sleep apnoea clinics where they do not normally come with a diabetes problem, there are quite a few patients with diabetes who are undiagnosed, come to a sleep clinic complaining of sleepiness so it could be a marker of underlying diabetes as well.

NZ:               What makes sleep apnoea such an important factor in the treatment of diabetes?

ST:                For several reasons, one is that if patients are sleepy then they are less likely to respond to their treatment advice and have enough cognitive ability to be able to undertake the changes that are necessary for their diabetes to improve, also because obstructive sleep apnoea puts up blood pressure, it increases risk of stroke and abnormal heart rhythm and diabetes patients are at risk because of that and also sleep apnoea may be associated from the diabetes complications and also lead to macrovascular complications which affect large blood vessels giving heart attacks and strokes but also microvascular complication associated with eye disease, nerve disease and kidney disease.

NZ:               Sleep apnoea is both under-diagnosed and under-treated, why is this?

ST:                Mainly because we do not think about it and if you look at the science of sleep apnoea basically it is a fairly young science so it is not really out there in terms of clinical awareness so there are lots of patients with diabetes who are sitting in diabetes clinics now who have no idea they have sleep apnoea and also their clinicians were not aware of it either.  The clinical awareness is the most important factor that determines lack of diagnosis of sleep apnoea.

NZ:               Is this under-diagnosis primarily an issue in primary care or is it seen in specialist care as well?

ST:                The issue is there is a cross level of care because as you know the majority of the patients are in primary care so that is missed out as well.  In my view any diabetes patient who comes for their annual review should be assessed for all the various factors, including sleep apnoea.

NZ:               What are the most important risk factors for sleep apnoea that a primary care team should be aware of in patients with diabetes?

ST:                Generally obesity is the main driving factor although not the only driving factor, so a patient with obesity with high body mass index, patients who have particularly wide neck circumference, for example men who wear shirt collars of greater than 17 are at high risk of having sleep apnoea.

NZ:               And finally Dr Taheri, how is sleep apnoea diagnosed in primary care?

ST:                Questionnaires have been used to identify patients who have high risk of sleep apnoea.  The problem with this questionnaire is that they are not always very good at doing that so the easiest way to actually screen patients is to do what we call an oximetry which is measuring oxygen levels during the night and it is a fairly simple procedure to do and that should allow us to identify the majority of cases.  Of course we will not be able to pick up all the cases because the equipment is not geared towards picking up more difficult cases but it can pick up the majority of the cases.

NZ:               Dr Taheri, thank you so much for joining us today.