- SK120_1Diabetes care Diabetes complicationsAbout this free courseThis free course provides a sample of Level 1 study in Science: http://www.open.ac.uk/courses/find/science.This version of the content may include video, images and interactive content that may not be optimised for your device.You can experience this free course as it was originally designed on OpenLearn, the home of free learning from The Open University - www.open.edu/openlearn/science-maths-technology/science/biology/diabetes-complications/content-section-0.There you’ll also be able to track your progress via your activity record, which you can use to demonstrate your learning.The Open University, Walton Hall, Milton Keynes, MK7 6AACopyright © 2016 The Open UniversityIntellectual propertyUnless otherwise stated, this resource is released under the terms of the Creative Commons Licence v4.0 http://creativecommons.org/licenses/by-nc-sa/4.0/deed.en_GB. Within that The Open University interprets this licence in the following way: www.open.edu/openlearn/about-openlearn/frequently-asked-questions-on-openlearn. Copyright and rights falling outside the terms of the Creative Commons Licence are retained or controlled by The Open University. Please read the full text before using any of the content.We believe the primary barrier to accessing high-quality educational experiences is cost, which is why we aim to publish as much free content as possible under an open licence. If it proves difficult to release content under our preferred Creative Commons licence (e.g. because we can’t afford or gain the clearances or find suitable alternatives), we will still release the materials for free under a personal end-user licence.This is because the learning experience will always be the same high quality offering and that should always be seen as positive – even if at times the licensing is different to Creative Commons.When using the content you must attribute us (The Open University) (the OU) and any identified author in accordance with the terms of the Creative Commons Licence.The Acknowledgements section is used to list, amongst other things, third party (Proprietary), licensed content which is not subject to Creative Commons licensing. Proprietary content must be used (retained) intact and in context to the content at all times.The Acknowledgements section is also used to bring to your attention any other Special Restrictions which may apply to the content. For example there may be times when the Creative Commons Non-Commercial Sharealike licence does not apply to any of the content even if owned by us (The Open University). In these instances, unless stated otherwise, the content may be used for personal and non-commercial use.We have also identified as Proprietary other material included in the content which is not subject to Creative Commons Licence. These are OU logos, trading names and may extend to certain photographic and video images and sound recordings and any other material as may be brought to your attention.Unauthorised use of any of the content may constitute a breach of the terms and conditions and/or intellectual property laws.We reserve the right to alter, amend or bring to an end any terms and conditions provided here without notice.All rights falling outside the terms of the Creative Commons licence are retained or controlled by The Open University.Head of Intellectual Property, The Open UniversityDesigned and edited by The Open University978-1-4730-1217-2 (.epub)
978-1-4730-1985-0 (.kdl)IntroductionThis course is designed to inform people from a variety of backgrounds about diabetes and its management. You might be hoping to learn more about diabetes because you plan to have a career in the health services, or you may be caring for someone with this condition, or you may have diabetes yourself. Whatever your reasons for viewing these pages we hope that you are able to learn more about the processes that cause diabetes and how Type 1 and Type 2 diabetes are treated. You should know about the signs and symptoms of the condition, and should appreciate how they would affect the day-to-day life of that person.The aim of managing diabetes, therefore, is to enable affected people, as far as possible, to feel well enough to live the sort of life they would have lived if they did not have the condition. However, apart from improving the quality of life of the person with diabetes, the correct management of both types of diabetes reduces the risks of the long-term complications that can develop if the condition is poorly controlled. This course examines the factors that increase these risks, how they are monitored, and who performs the tests associated with these risks.This OpenLearn course provides a sample of Level 1 study in Science.After studying this course, you should be able to:define and use, or recognise definitions and applications of, each of the terms printed in bold in the textlist the investigations that should form part of a diabetes annual reviewdiscuss the role of different diabetes team members in performing the investigations for an annual reviewappreciate the range of results for the various tests carried out at the annual reviewexplain which risk factors are associated with particular diabetes complications.1 Assessing diabetes complication risk factors1.1 Having testsThe following story (Case Study 1) illustrates that diabetes care is about more than checking your blood glucose level regularly. However, it can be difficult for people to understand why certain tests need to be taken and what the results mean. This can lead to them not following treatment, or indeed not even having the tests done.Case Study 1Mrs Begum attends a hospital diabetes clinic (such as that signposted in Figure 1) for her diabetes annual review. She does not speak English, so she has brought her 14-year-old daughter with her to interpret. She cannot understand why she has been asked to attend the clinic because she only has ‘mild’ diabetes, treated with tablets. The clinic is so crowded, with people who look much sicker than she is. She does not feel she has anything wrong with her, because she does not feel ill. When she eventually gets to see the doctor, he tells her she must take some more tablets to control her blood cholesterol, because the results of a previous blood test showed it was high.Try to imagine what it is like for someone like Mrs Begum (Case Study 1) attending a busy diabetes clinic, and not understanding what is being said or done. For example, what difficulties do you think can arise when a family member is used to interpret in this situation? Why does Mrs Begum think she has ‘mild’ diabetes? Do you think she will take the cholesterol-lowering tablets?The diabetes annual review consists of numerous tests, which can be confusing or disconcerting for anyone with diabetes who does not understand what they are for. This course describes what these tests are, why they are important, and the purpose of them. Mrs Begum may not get a clear explanation from her daughter who is interpreting for her. This may be because the daughter does not understand the explanation given to her by the doctor, or it may be because her daughter wants to protect her mother from worrying about the results of the tests. This may be the reason why Mrs Begum believes she has ‘mild’ diabetes. Alternatively, her doctor or nurse may have told her that she has ‘mild’ diabetes. This can unfortunately happen sometimes in the mistaken belief that Type 2 diabetes is somehow not as serious as Type 1 diabetes, because usually it can be managed, at least in the early stages, by diet or diet and tablets rather than requiring insulin injections.All people with diabetes are at risk of diabetes complications if their diabetes is not controlled. The good news is that the risk factors and early signs of this damage can be picked up at the diabetes annual review, and then the person with diabetes can work with their diabetes team to prevent or limit the damage. You can see, therefore, that without an understanding of what cholesterol is, and what damage it can do, Mrs Begum may not take her cholesterol-lowering tablets.1.2 Discovering the risksThe incidence of diabetes is dramatically increasing both nationally and worldwide. This is of great concern because of the debilitating day-to-day effects of the condition if it is not controlled, but in particular, because of the long-term damage that diabetes causes to blood vessels and nerves in the body.In the short term, people with poorly controlled diabetes can suffer any or all (or, in fact, none) of the following complications:tiredness and lethargy;depression and change of mood;thirst;passing large amounts of urine frequently (a condition known as polyuria);loss of weight;genital itching.Sometimes, as with Mrs Begum, there are no obvious signs or symptoms of the condition. This can make it difficult to see the diabetes as serious and so taking tablets regularly or attending clinics for diabetes checks may not be seen as important.However, the possible long-term complications (irrespective of any short-term complications) include:coronary heart disease (CHD), which includes angina and heart attacks;cerebrovascular disease (strokes);nephropathy (damage to the kidney which can lead to kidney failure);peripheral vascular disease (which can lead to gangrene of the feet);retinopathy (damage to the blood vessels in the retina at the back of the eye);autonomic neuropathy (damage to nerves which can lead to erectile dysfunction (i.e. impotence), chronic diarrhoea, and other problems)peripheral neuropathy (damage to nerves to the extremities, causing painful or numb feet).Much of the focus of diabetes management is based on the early detection of these complications and their prompt treatment. However, just as important is the detection of factors in the person with diabetes that increase their risk of developing such damage. By correcting these risk factors, the chance of developing diabetes complications can be avoided, delayed, or the complications reduced in severity. The checks for these risk factors are included in the diabetes annual review.What are the risk factors? High blood glucose (hyperglycaemia) does cause the short-term complications described above, and contributes to some of the long-term damage, particularly to nerves and small blood vessels. As the blood vessels involved are small, these are called microvascular complications. Retinopathy is an example of a microvascular complication. However, high blood glucose is not the only cause of diabetes damage. High blood pressure (hypertension; see Section 5) and abnormal blood fat levels (dyslipidaemia; see Section 4) are also major contributing factors particularly in the development of complications such as CHD and cerebrovascular disease. These are known as large blood vessel diseases or macrovascular complications because of the blood vessels affected.Exercise 1What other factors increase the risk of heart attacks and strokes in the general population?You probably thought of smoking, lack of physical activity, being overweight, excessive alcohol intake, an unhealthy diet consisting of high fat, high sugar, high salt, and a lack of fibre.These factors are all important when considering the risk someone with diabetes has of developing diabetes complications. Other risks may be less obvious and include a difficult social situation, low income level, poor learning ability, a lack of knowledge in self-management of diabetes, old age, mental health problems and stress.However, that is not to say that every person with diabetes will develop complications if they have high blood pressure, poor long-term blood glucose control and high cholesterol levels. People often cite the person they know who has had long-term high blood glucose but has never developed eye disease (retinopathy), for example. However, many medical studies over the years tell us that there is a greater likelihood of developing diabetes complications if the condition is not well controlled. A complete picture of these factors is therefore crucial to assess the person: to guide medication choice, to identify education needs, to offer other interventions such as advice on giving up smoking, but most importantly, to give the person with diabetes a clear and honest view of their risk so they can make choices about how they manage the condition.1.3 The diabetes annual reviewThe function of the diabetes annual review is to identify risk factors. The GP or a doctor in the hospital diabetes team may perform this review, while other members of the team, for example the practice nurse in the GP surgery, or the diabetes care technician in the diabetes clinic, carry out many of the tests.Although some of the risk factors can be identified by physical tests (examples include blood tests to check cholesterol level, or measuring blood pressure), much of the information required to judge risk factors (such as dietary and smoking history, or home blood glucose monitoring results) is obtained by careful discussion between the health care professionals and the person with diabetes. (See Case Study 2.)Case Study 2Janet has had Type 2 diabetes for four years. She takes her diabetes tablets regularly each day, tries to eat a healthy diet, and usually has a brisk walk on most days. She checks her blood glucose level with a meter several times a week, and feels satisfied that her diabetes control is within the target range she agreed with the doctor. She has arrived for her annual review with a urine test, her medications, and her blood glucose record book. She had some blood tests taken two weeks ago so the results would be available to discuss with her doctor. Although she feels well, she is keen to find out if her diabetes is as well controlled as she thinks it is.You can see then, that an annual review is a team effort, with the person with diabetes as the focus (Figure 2).Activity 1 Sharing personal information 0 10 It is important that people with diabetes feel able to share information with their health care team, about their lifestyles and the difficulties they may be facing as they try to make changes.Describe to someone the food you ate yesterday. Make a note of their reactions to what you had eaten and any responses they give. Did the person react in a non-judgemental way or did you feel they disapproved of any of the foods you ate? How did you know? Did they use words like ‘naughty’ or did you notice a change in their facial expression?We've suggested discussing food for this activity because diet can be an emotive subject, with many people having a reasonable knowledge about what they should be eating, and feeling guilty if they are not using this knowledge. Hopefully, every health care professional, when asking the patient to share honest information, will ensure privacy and confidentiality and receive information in a non-judgemental way. Comments like ‘what?!’ and ‘really?’ express disbelief and incredulity, and therefore are judgemental. If you have diabetes this may discourage you from sharing information, which may create barriers to having useful conversations with health professionals.Apart from diet, information on many of the risk factors mentioned above needs to be obtained through discussion with the person with diabetes and/or their partner or carer. This process is described as taking the patient's history. It includes collecting information on smoking history and units of alcohol consumed, family history of diabetes and related diseases like heart problems, and the amount of exercise taken weekly. It is often done formally and noted in the medical records by a doctor, but is also done informally, for example by the nurse or diabetes care technician asking how someone is managing with dietary changes when weighing them at the clinic. Some information can be more difficult to obtain, particularly if it relates to stressful situations at home that may impact on other risk factors like adherence to a healthy diet or number of cigarettes smoked. This information may be offered later when a trusting relationship has developed between the health care professional and the person with diabetes.Exercise 2What could prevent you giving information to a doctor or nurse at the clinic?You may have thought of several factors, but probably a lack of privacy and trust will be among them. You may not want to discuss the number of cigarettes you smoke for example, if you think the doctor will reprimand you.1.4 What monitoring is carried out at the annual review?The diabetes annual review consists of a series of tests to monitor risk factors as well as the presence of any signs of diabetes complications. It also involves an assessment of the self-management skills of the person with diabetes, and their understanding and control of blood glucose. It therefore gives the opportunity for the early detection of diabetes complications and identification of risk factors for developing them – these risk factors are outlined in the following sections.2 Monitoring blood glucose levels2.1 Blood glucose levelsMost people with diabetes are encouraged to keep their day-to-day blood glucose level between 4 and 7 mmol/l before meals. This is very similar to the blood glucose range of someone who does not have diabetes. However, this can be very difficult to achieve, and if you have diabetes, you should agree the ideal range for you with your diabetes team.Two large diabetes research trials have shown that by maintaining a blood glucose range as near to the normal range as possible, the chances of developing long-term complications can be prevented, reduced or delayed. These trials were conducted in the Diabetes Control and Complications Trial (DCCT, 1993; see Box 1) and the UK Prospective Diabetes Study (UKPDS, 1998; see Box 2).Box 1 The Diabetes Control and Complications Trial (DCCT)This trial compared people with Type 1 diabetes who had intensive treatment to keep very good control of their blood glucose level, with people with Type 1 diabetes who had conventional treatment, and did not manage to achieve such good control. Intensive treatment involved four injections of insulin daily, frequent home blood glucose testing, regular visits to clinics, and telephone calls from diabetes nurses. The trial, which reported in 1993, was conducted in the USA over a period of nine years, with over 1000 people involved. It demonstrated very clearly that keeping good control of blood glucose dramatically reduced the risk of developing diabetes complications involving small blood vessels (i.e. microvascular complications), and slowed the progress of damage in people who already had complications like diabetic retinopathy (eye disease) and nephropathy (kidney disease).Box 2 The UK Prospective Diabetes Study (UKPDS)This study looked at the effect of blood glucose (and blood pressure) control in people with Type 2 diabetes. It was carried out over 20 years in the UK, reported in 1998, and involved over 3000 people. Like the results from the DCCT, it also showed that keeping good control of blood glucose reduced damage to small blood vessels and nerves. However, it concluded that even with a lot of support from the diabetes team, it can actually be very difficult to achieve good control.The evidence from these two studies has been used to encourage people with diabetes to make and maintain lifestyle changes, take medication regularly, and to adjust insulin doses or seek advice if their blood glucose is not staying within their agreed limits. Assessing whether this is being achieved can be done in two ways:self-monitoring of blood glucose (Section 2.2) or for the presence of glucose in the urine (Section 2.3)regular monitoring of HbA1c (glycated haemoglobin, Section 2.5).2.2 Self-monitoring of blood glucoseMany people with diabetes are encouraged to monitor their blood glucose as it gives them immediate feedback to help them in the day-to-day management of the condition. It can help them to make decisions about lifestyle changes and choices, and to adjust their medication as required (Figure 3). It can therefore be a powerful education and empowerment tool if the person using it has been trained properly in how to do the test correctly and to know what to do with the test results. (Empowerment is an important concept in diabetes management and involves people managing their condition themselves, and making informed choices about their treatment.) However, at the time of writing (2005), there is considerable controversy about whether only people on particular diabetes treatments should be encouraged to do the tests. This is because the cost of the blood testing equipment is relatively high, and in some areas, more money is being spent on the equipment than on the tablets used to treat diabetes. Unfortunately, many people test their blood glucose regularly but do not use the results constructively (often because they have not been shown how to adjust their medication or where to access advice), and therefore the expense of the tests is not justified by an improvement in blood glucose control and a reduction in diabetes complications.Activity 2 What does Diabetes UK, which represents people with diabetes, say about self-management? 0 20 Look at the Diabetes UK website and read the position statement on ‘Glucose Self-monitoring in Diabetes’ (Diabetes UK, 2003).You will see that Diabetes UK takes the stance that all people with diabetes should be able to test their blood glucose as often as they feel is necessary. However, the National Health Service has a limited budget, and money spent in one area of care means less money for another area. Primary Care Trusts (PCTs), which control budgets for prescribing, may try to limit the number of blood glucose strips being prescribed by the GPs in their locality. Primary Care Trusts are made up of GPs and other health care professionals and are responsible for planning health care services for a local population.To monitor their blood glucose, people may be given, or may purchase from a pharmacy, a blood glucose meter. This is a device for analysing the glucose content of a small sample of capillary blood, usually obtained from a finger, which is placed on a disposable testing strip and then inserted into the meter. There is a variety of meters available (Figure 4), each using a particular blood glucose-testing strip. The strips are available in containers of 50, and are supplied on prescription from the patient's GP via their local pharmacist.Activity 3 Finding out about choosing a blood glucose meter 0 30 The next time you are out shopping, visit a local pharmacy and look at the range of blood glucose meters available, or if you have access to your local diabetes centre, ask to see their selection of meters. Compare their size, weight, price, the technique for using them, and the blood glucose strips recommended for use with them.You may find several meters on display in your local pharmacy. They vary in price depending on additional functions. Some are very small and can be carried discreetly in your pocket. However, for people with poor eyesight a meter with a large display may be more suitable.A person using a blood glucose meter must learn how to use the device correctly (Box 3), especially if they are then using the results to adjust medication. As you saw from Activity 3, there are several types of blood glucose meter available, all with different methods of use, and all requiring a particular brand of blood glucose-testing strip. If you have diabetes, it is important to find a meter that you find easy to use, and has the functions you require to manage your diabetes. For example, some meters have a large memory, which means the results can be downloaded onto a computer. This is useful if you want to look at trends in your blood glucose level over a period of time.Box 3 Accurate blood glucose monitoringSome procedures are common to all blood glucose meters, whether you or your carer is doing the test.Make sure you have the correct strips for the meter you are using. They are all brand-specific, and a meter will not work accurately with the wrong strips.You must always wash your hands before testing your blood glucose. Any substance on your fingers will contaminate the strip and can give an inaccurate reading.The meter must be correctly calibrated for the strips in use. This may involve inserting the chip included in the strip packet into the meter each time a new box is opened, or typing in a code number stamped on the package.Check that the strips have not expired, and that they have been stored at room temperature.Make sure you have an appropriate device for pricking your fingertip. Needles should not be used. Lancets are available on prescription and should be used once only.You should prick the side of your finger (Figure 5), avoiding the thumb and forefinger as the skin on these digits is tougher from greater use. Using the side is also less painful than the centre of finger pads. Allow a few seconds for bleeding to start, to allow a sufficient drop of blood to form.Read and follow the meter instructions carefully!The sharp lancets that have been used to obtain the blood sample from the finger, or alternative site, must be disposed of carefully. The safe disposal of sharp devices that can transport viruses and infection from one person to another is extremely important. In the diabetes clinic or surgery, sharp devices (lancets and needles) can be safely disposed of in designated sharps boxes or bins (Figure 6a). Unfortunately, you may find that the procedure for disposing of lancets, blood-contaminated strips and tissues, and used needles from insulin devices, is not straightforward outside the hospital or clinic environment. Some local councils provide a sharps disposal service by supplying individuals with sharps boxes and collecting them when they are full. Other areas recommend the use of a ‘safe-clip’, a small device for clipping off the needle and lancet point, which is then retained within the clip (Figure 6b). The remainder of the lancet, needle base, and blood contaminated tissue and strips should be stored in a screw-top container such as an empty bleach bottle (Figure 6c). When the clip and bottle are full, they are placed in the household rubbish.Exercise 3Can you think of any disadvantages of having a sharps box delivered and collected from an individual's house by the local council refuse department?The person may be concerned about their privacy. They may not want their neighbours to know they have diabetes. What happens if the person was out when the box is to be collected? Would it be safe to leave the full box on the doorstep?If a blood glucose meter is used competently, home blood glucose results provide valuable information about the user's daily management of their blood glucose level and this often helps to increase their understanding about the condition. The results are usually recorded in a blood glucose monitoring book or can be downloaded from a computer and printed out as a graph. The record contributes to the assessment carried out during the annual review. As seen in the DCCT and UKPDS studies, long-term complications from a persistently high blood glucose level can occur particularly in small bloodvessels.2.3 Self-monitoring of urine glucoseSome people may choose not to test their blood glucose. They may instead test for the presence of glucose in their urine as a measure of blood glucose control. In someone without diabetes, the amount of glucose in the blood does not reach such a high level that the kidneys start to transport it into the urine. This level is called the renal threshold and in most people, is about 10 mmol/l. If the level of glucose rises to above this amount in the blood of someone with diabetes, then glucose starts to appear in the urine. By testing their urine at regular intervals, someone with diabetes can see if the amount of glucose in their blood has risen above the normal range (i.e. 10 mmol/l) since they last passed urine. If their diabetes is well controlled, they would find most of their urine tests would be negative (i.e. no glucose in the urine). Of course, to be effective, this test assumes that the person has a normal renal threshold. If their kidneys do not start to remove glucose into the urine until the level of glucose in the blood reaches, say, 15 mmol/l, they may have negative urine tests (i.e. a ‘normal’ result) despite having poorly controlled blood glucose. This can occur commonly as people get older, and is described as having a high renal threshold. Sometimes, people have a low renal threshold, where glucose appears in the urine when the blood glucose level is normal. Both high and low renal thresholds can occur in healthy kidneys, and does not necessarily mean there is kidney damage, but it does mean that urine testing is not a suitable method for blood glucose monitoring.Exercise 4Why would someone choose not to test their blood to check his or her diabetes control?Blood testing can be painful. Some people with poor vision or manual dexterity problems (severe arthritis, for example) may not be able to use a glucose meter. Some people feel anxious about the results they get, especially if they do not know what to do about them. In addition, some GPs restrict the prescriptions of blood testing strips to people using certain types of diabetes treatments because of the costs of testing strips (as mentioned above).2.4 Venous blood samplingThe most accurate method for measuring blood glucose is to take a sample of blood from a vein (a venous sample) that is then tested in a laboratory. (This will result in a plasma glucose level.) This is always done when diagnosing diabetes – a capillary sample used with a blood glucose meter or a urine test is not accurate enough for a diagnosis. Venous samples are also used for many other blood tests which are important in identifying changes which may lead to long-term complications in people with diabetes.Veins are large, thin-walled blood vessels which carry blood back to the heart. The most commonly used vein for venous blood sampling is found in the antecubital fossa, that is the area inside the bend of the elbow (Figure 7a). As you can see in this diagram, there are many veins in this area that are close to the surface of the skin. If there is difficulty in getting blood from these veins, other sites such as the back of the hand may be used.The equipment needed to take a venous blood sample is of two sorts. Either a syringe and needle is used, or a closed vacuum system and needle. The closed vacuum system (also known as a venepuncture vacuum system) has the advantage of enabling several samples to be taken safely at any one time by reducing the risk of blood spillage and needle-stick injury to the person taking the sample (Figure 7b). Venepuncture literally means ‘puncturing the vein’ and is used to describe a needle entering a vein through the skin.Before blood is taken, it is important that the person with diabetes understands what is going to be done and why, and has given their consent. The person taking the blood should always wash their hands before they start the procedure and wear a fresh pair of gloves.The equipment used in taking a blood sample includes:disposable glovesalcohol swabtourniquetneedle and syringe, or venepuncture vacuum systemspecimen tubessharps boxcotton wool balls and adhesive tapeformsplastic bag.Exercise 5Can you think what all these items are required for?You probably thought of at least some of the following:Disposable gloves: these are used to protect the person taking blood from any accidental blood spillage. Gloves offer some protection from infection risk should a spillage happen. They also help to protect the patient from any bacteria on the health professional's hands, though this person should always wash their hands even when using gloves.Alcohol swab: this is used to clean the patient's skin before it is punctured to take the blood sample. The alcohol should be left to dry for at least five seconds before the sample is taken; this kills most of the bacteria on the skin so that they cannot enter the blood when the needle enters the vein through the skin.Tourniquet: this is an elasticated strap used to compress the vein above the proposed site of the injection, allowing the vein to be seen more easily and felt more readily. The tourniquet should be put on tightly enough to raise the vein but not so tightly that arterial blood flow is stopped. Tourniquets should not be left in place for any longer than two minutes, in order to avoid injury. Tourniquets that are left on too long can make the arm quite painful.Venepuncture vacuum systems: these are closed systems used for collecting blood samples. The vacuum in the specimen tube causes the blood to be drawn directly into it (see Figure 7b). Risk of blood spillage is reduced as each specimen tube can be attached in turn to the system.Needles and syringes: these are used to obtain the sample of blood when a venepuncture vacuum system is unavailable or not suitable, such as when the patient's veins appear fragile. Needles and syringes come in various sizes and a suitable size should be chosen. The needle should remain sheathed when being applied to the syringe and until the sample is about to be taken. It should not be resheathed after use as this increases the risk of a needle-stick injury. Used needles should be placed in a sharps box.Specimen tubes: blood samples are placed in these after collection by the needle and syringe method. There are different types of sample tube depending on the laboratory test to be done. Labels on the specimen tubes must be accurately completed, including the patient's name and identification number. (See, for example, Figure 8.)Sharps box: this is needed for the safe disposal of needles and other used equipment. (See, for example, Figure 6a.)Cotton wool balls and adhesive tape: these are needed to apply pressure to the vein following the procedure, to avoid haematoma formation (the leakage of blood forming a large bruise) at the site. A small adhesive dressing may be used after bleeding has stopped.Forms and plastic bags: the forms accompany the specimens to the laboratory in plastic bags to give the patient's details and request the required tests. An appropriate form, accurately completed, accompanies each specimen. In the laboratory, the details on the specimen tube are checked with the details on the form, to make sure the correct tests are performed for the correct patient.2.5 HbA1c levelsAnother way of assessing blood glucose control is by measuring the glycated haemoglobin. This test is abbreviated to HbA1c . Haemoglobin is a protein that is found in red blood cells and its function is to transport oxygen around the body. Red blood cells are functional for about 90 days, after which they are broken down in the spleen, along with the haemoglobin contained within them. Glucose reacts with protein over time, changing it (or ‘glycating’ it). By taking a sample of red cells and measuring how much of the haemoglobin within them has been changed by this process, the result gives an idea of what the blood glucose level has been like in the last two to three months for that person. If the blood glucose level has been high, a greater proportion of the haemoglobin will have been in contact with glucose and will have become glycated than if the blood glucose level has been normal or low. This is a process that occurs even in someone without diabetes, so there is a ‘normal’ range of glycated haemoglobin. The aim of diabetes treatment is to enable someone to control their blood glucose as well as possible so that their HbA1c result is similar to that of someone without diabetes. The result is measured as a percentage of total haemoglobin changed, and depending on the techniques used in your local laboratory, the normal result is usually less than 6.5 per cent. Guidance from NICE (the National Institute for Health and Clinical Excellence) recommends that most people with diabetes should aim for results of between 6.5 and 7.5 per cent or less (NICE, 2002). The GMS2 (General Medical Services) contract also encourages GPs to help at least 50 per cent of their patients to get this result. However, it is very difficult for most people to achieve, particularly if the risk of hypoglycaemia is too high. If you have diabetes, and are not able to achieve this target, you should be reassured that any reduction in HbA1c will reduce your risk of developing microvascular complications.Activity 4 Finding out about HbA1c testing 0 10 Find out what is considered to be the normal range for HbA1c at your local diabetes clinic. If you have diabetes yourself, do you know what your last result was, and is it within the target range? Also, check how HbA1c is measured at the clinic.HbA1c can be checked using a venous blood sample which is sent to the laboratory, or your diabetes clinic may use a machine that analyses a finger-prick capillary sample of blood, where the result is available within a few minutes.3 Monitoring ketone levelsKetones, which are formed when fats in the body are broken down, are an alternative energy source, and are usually only present when there is insufficient glucose to meet the body's energy requirements. They can occur in small quantities in someone without diabetes, after prolonged fasting. The presence of insulin, however, normally suppresses the production of significant amounts of ketones. In people with Type 1 diabetes who are deficient in insulin (perhaps because they have forgotten to take their insulin injections, for example), ketones can be produced in large amounts because, although there is plenty of glucose available in the blood, the body is unable to use it for energy without insulin. Ketones accumulate in the blood, altering the acidity (the pH level). They are removed from the body in the urine and via the lungs in the breath. They have a distinctive ‘pear-drop’ smell or nail varnish type odour, which you may notice on someone's breath when you are close to them.In people with diabetes, ketones are a sign of very poor diabetes control. If ketones build up in sufficient quantities in the blood, the condition of diabetic ketoacidosis (DKA) develops , which is a medical emergency. Testing for ketones when the blood glucose is high, especially if the person with diabetes is unwell, is essential to identify DKA, or to prevent it developing further, by treatment with fluids and insulin.Ketones can be detected in the urine by using a reagent strip (Figure 9). Usually the testing strip consists of a white plastic strip with a coloured pad stuck to it. The pad for ketones may be one of several pads for various tests if the urine is being tested at the GP surgery or hospital clinic. The pad is dipped briefly into a specimen of urine, and then examined after the recommended time (usually about 30 seconds) for a change in colour. The intensity of the colour change depends on the amount of ketones in the urine. No colour change means there are no ketones in the urine, and is said to be a negative result. A very strong colour change means that ketones are present in high quantities, and treatment to prevent DKA is required urgently.People with Type 1 diabetes can obtain ketone testing strips on prescription from their GPs. It is useful to have a supply available to test for ketones during periods of illness, when people may be more likely to develop DKA. By frequently testing the blood glucose and ketones, the person may be able to make decisions about adjustments to their insulin dose to avoid hospitalisation with DKA, or at least recognise that they need to contact a health care professional for advice.The presence of ketones in the blood is usually tested in a hospital laboratory. However, at the time of writing (2005), one blood glucose meter on the market has the facility for home testing of blood ketones using specific strips. However, most people use urine testing to detect ketones.4 Monitoring lipid levelsAnother common blood test that is often taken at the same time as the venous blood sample for HbA1c is for the lipid profile. Lipids are fats, and they can be found in the blood. The target for ideal blood lipid level has changed recently, as new evidence is gathered from research. This test measures the total level of cholesterol in the blood, what proportion of that cholesterol is made up of LDL (low-density, harmful, lipoprotein) cholesterol and HDL (high-density, protective, lipoprotein) cholesterol, and the level of another type of fat called triglycerides. Abnormally high levels of lipids, in particular triglycerides and LDL cholesterol, and low levels of the protective HDL cholesterol, are common in people with Type 2 diabetes. This abnormal profile is termed diabetic dyslipidaemia and increases the risk of CHD, and so these factors are checked at least annually to ensure the results are well within the normal range. Drug treatment is recommended, in conjunction with a healthy lifestyle, to reduce the person's risk of CHD by trying to achieve as near normal a level of blood lipids as possible. The treatment includes drugs called statins and fibrates. The proportions of the different lipids in the blood determine the GP's choice of medication.Activity 5 Finding out about cholesterol levels 0 5 Do you know what your cholesterol level is? Ask some of your friends and colleagues if they know their levels.You may be surprised at how many people know their cholesterol level. People without diabetes can have abnormal cholesterol levels too, and there is an increased public awareness nowadays of the risk of a raised cholesterol level. (Ideally, the level of total-cholesterol should be about 5 mmol/l.) Some pharmacists offer on-the-spot cholesterol tests, which anyone can use. If someone has high blood pressure, for example, his or her practice nurse may also have checked their cholesterol as part of their CHD risk profile.5 Blood pressure monitoringHigh blood pressure (hypertension) is another common problem in people with diabetes, particularly Type 2 diabetes. Along with dyslipidaemia, it is strongly associated with a high risk of developing CHD. As a consequence, blood pressure should be checked at least annually, but is usually checked at every diabetes clinic visit, especially if it is above normal. Blood pressure in people with diabetes should be 140/80 or less, and they may need to take several different tablets to get to this level. (Blood pressure is measured in units of millimetres of mercury (mmHg) but normally the units are not quoted.) If you have diabetes, you may have been advised to try and attain an even lower level, particularly if you know you have diabetes complications. Like blood glucose control, it can be very difficult to achieve the desired target, but again, any reduction in blood pressure is beneficial. The UKPDS (see Box 2) showed that reducing blood pressure was more effective than control of blood glucose in reducing macrovascular disease (such as heart attacks and stroke).Blood pressure simply means the force with which the blood pushes onto the walls of the blood vessels as it flows through them. This force is produced by the pumping action of the heart pushing the blood around the body, and the elastic nature of the blood vessels which allows them to stretch as the blood is pumped into them, and spring back afterwards when the heart is relaxing to push the blood onwards. If you had no blood pressure you would be dead; this would occur if the heart stopped pumping. However, if the blood vessels become less elastic, the heart has to work harder to pump the blood through them and this can lead to many problems, such as heart failure. People with diabetes are very prone to developing inelastic blood vessels as a result of the build up of atheroma, a fatty substance which causes narrowing of the arteries and also makes them much less elastic. This can then result in problems such as heart attacks and strokes. High blood pressure is an indication that the arteries are becoming less elastic (although there may be other reasons for high blood pressure). This is why it is so important that the blood pressure is checked regularly and accurately, and treatment started if the blood pressure is higher than normal. It is also very important that the equipment is properly maintained so that accurate readings are obtained.Blood pressure is measured by using a manual or electronic measuring device (a sphygmomanometer), which measures the pressure of blood in the arteries (Figure 10).The two numbers given when quoting blood pressure refer to the pressure of blood in the artery when the heart is contracting (systolic pressure) and the pressure of blood in the artery when the heart is relaxing (diastolic pressure).Exercise 6Which do you think is the higher measurement?The systolic is the higher reading because this is when there is a surge of blood into the arteries.Many people are used to having their blood pressure measured. However, for some people, the annual review may be the first time their blood pressure has been measured and they may be quite worried about it. Other people who have had their blood pressure measured before may also be worried in case they have high blood pressure. It is important therefore that the person taking the blood pressure explains what is going to happen, and why it is being done, and that the person being checked consents to the procedure. The blood pressure may also be raised if the person tested is very anxious or has been rushing to get to the appointment, so the person should be given time to relax before having their blood pressure measured.Exercise 7Mrs Ferguson's blood pressure was always higher when Dr Jones took it than when the nurse checked it. Why do you think this could happen?You may have heard of ‘white coat syndrome’, where a patient's blood pressure is higher when the measurement is taken by a health care professional than when the patient is relaxed in a familiar environment. Perhaps Mrs Ferguson feels more relaxed with the nurse or the nurse talks to her for a few minutes before checking the blood pressure.Blood pressure is measured by wrapping a cuff round the arm and inflating it, to compress the artery so that there is no blood going through the artery (Figure 11). This means that if the cuff is left inflated, it will be painful as the blood supply to the arm and hand is interrupted. As the cuff is slowly deflated and the pressure in the cuff gradually reduces, blood can start to pass back down the artery. By listening through a stethoscope held over the brachial artery in the antecubital fossa, the person doing the procedure can hear sounds from the time the blood re-enters the artery (systolic pressure) until the blood is flowing freely through the artery (diastolic pressure). This is the manual system and for this, a mercury or aneroid (air-filled) sphygmomanometer is used. Mercury, or more specifically its vapour, is highly toxic and therefore mercury sphygmomanometers are being phased out. If an electronic device is used, a cuff is still applied but the reading is taken automatically following automatic inflation and deflation of the cuff.Once the reading has been taken, it should be documented clearly in the record of the person with diabetes. If it is either too high or too low, the doctor may start treatment or adjust the current medication.Whenever your blood pressure is taken, it is important you know what the result is. This information will help you to make choices about your diet and exercise, and may give you some incentive to lose weight or try to give up smoking if these are problems for you. If you are concerned about the result, you should be able to discuss your worries with your doctor or nurse.There are devices available for people to check their blood pressure at home. They can take the blood pressure at the arm or wrist. The normal range of measurements varies according to the site where the blood pressure is taken and the age of the person. As with the use of blood glucose meters, it is essential that the user knows how to use the device properly, and knows what to do with abnormal results. If you are using one of these devices, you may find it helpful to take it with you when you attend your diabetes clinic appointment. You can then compare the result you obtain with your device with the result obtained at the clinic.The increased risk of CHD in people with Type 2 diabetes cannot be overemphasised. Any of the factors that cause CHD must be identified and treated if possible, because people with diabetes have such a high risk of developing the condition. Along with identifying hypertension, hyperglycaemia, and dyslipidaemia, lifestyle risk factors need to be assessed, and the person advised on behaviours that increase CHD risk. It may be very difficult to change behaviour, but people need to be aware of the risk involved and empowered to make changes if they choose, through education and initiatives such as support to give up smoking.6 Calculating body mass indexBeing overweight is another risk factor for CHD, as well as a risk factor for developing Type 2 diabetes. Assessing whether somebody is overweight can be done in two ways. Simply weighing someone may not accurately determine if they are overweight. For example, two people may weigh 70 kg but one may be of an average weight whereas the other person is obese. Height is an important factor in determining if the person's weight is healthy for them. To take this into account, the relationship between weight and height is determined by calculating the body mass index (BMI).A BMI of between 20 and 24.9 kg/m2 is desirable. A BMI of 25 kg/m2 or higher is overweight, and over 30 kg/m2 is classed as obese.The distribution of fat on the body is also significant; carrying fat around the abdomen is associated with highest risk. This is termed ‘central obesity’ and people with this distribution are described as ‘apple-shaped’. A simple assessment for central obesity is to measure waist (or girth) circumference in centimetres using a tape measure (Figure 12c). Ideally, waist circumference in men should be less than 94 centimetres (cm), and less than 80 cm in women. (You may see other values quoted in other sources as the exact value is open to debate.) If these values are exceeded it is an indication of excessive body fat around the abdomen. A further calculation that can be made is the waist to hip ratio. The waist should be measured at the level of the umbilicus (belly button) and the hips at the widest point. The waist measurement is divided by the hip measurement. Ideally the ratio should be 1.0 or less in men or 0.8 or less in women.Exercise 8Mrs Soames has a BMI of 29 kg/m2 with a waist measurement of 92 cm. Her husband also has a BMI of 29 kg/m2 with a waist measurement of 92 cm. Who has the higher risk of coronary heart disease?Mrs Soames has the higher risk. Although both of them are overweight, Mrs Soames has central obesity, with a waist measurement higher than is ideal for a woman.7 Making sense of the measurementsIt is clear that there are several risk factors that contribute to diabetes complications, and that must be assessed at least annually, and treated if possible to reduce the risk of damage. The risk factors for CHD are particularly important because of the very high risk that people with Type 2 diabetes have of developing this complication. To make sense of all the factors we have discussed above, a calculation can be made from measurements of blood pressure and lipids, and from taking into account factors like smoking, which can give a prediction of relative risk of having a coronary event in the next 10 years. This is called the Framingham CHD risk score. People having a high risk on this score need to have their risk factors treated aggressively. Unfortunately, most people with Type 2 diabetes fall into this category.The person with diabetes is the central and most important member of the diabetes team. It is important that they are aware of their targets for blood pressure, HbA1c, and lipids, what their values actually are, and the presence of other risk factors for diabetes complications. With this information, they may decide to make changes in their behaviour and lifestyle, to reduce their risk of other health problems. It is their choice, but without all the information they cannot make that choice. It is therefore important that they are informed of the result of any test performed on them. If they do not understand the significance of this information, an appropriate health care professional like a GP or nurse should explain it to them. All test results should also be clearly marked on their patient-held record card so they can compare their progress over time.8 Final questionsThe Learning Outcomes can be found at the start of this courseQuestion 1 (1st, 2nd and 3rd Learning Outcome)List the investigations that are likely to take place during a diabetes annual review and the various team members involved.Various investigations take place during an annual review. They include reviewing blood glucose control, measuring levels of HbA1c and ketones in the blood and determining the lipid profile. Blood pressure is measured and the BMI is determined along with waist measurement. Lifestyle, including diet history, smoking and exercise is discussed.Various members of the diabetes team are involved in the annual review, for example the diabetologist, dietitian, and diabetes care technician.Question 2 (2nd Learning Outcome)Which tests in the diabetes annual review check for coronary heart disease risk?The tests that contribute to the checks for risk of coronary heart disease are: blood pressure, blood lipid profile, smoking history, lifestyle, BMI and waist measurement.Question 3 (4th and 6th Learning Outcome)Mrs Smith feels her diabetes is well controlled because her home blood glucose test results are all in single figures. When she attends the diabetes clinic with her GP for her annual review, she is shocked to find her HbA1c is well above target. Can you suggest possible reasons for this?There are several possible reasons why Mrs Smith’s HbA1c level is high. Her meter could be faulty, she may not be using it correctly, she may be using the wrong strips or they could be out of date or damaged. She may be testing infrequently and only when she knows her tests will be satisfactory. She may be only testing at a certain time of day and missing high results at other parts of the day. There could be an abnormality with her haemoglobin which is giving a high HbA1c, or there may be a problem with the laboratory equipment (these last two reasons are very unusual).Question 4 (4th Learning Outcome)Explain how the HbA1c result can give a picture of diabetes glycaemic (i.e. the level of glucose in the blood) control.HbA1c measures the amount of haemoglobin in the blood that has been changed or glycated by the prevailing blood glucose concentration over the previous two to three months. If the blood glucose has been within normal limits for most of the time, the HbA1c is likely to be normal. If the blood glucose has usually been higher than normal, then a greater percentage of haemoglobin will have been in contact with glucose and therefore glycated. The HbA1c will therefore be higher than normal. If the blood glucose has been lower than normal (because the person with diabetes has had a lot of episodes of hypoglycaemia or low blood glucose) then the HbA1c value will be lower than normal. Unfortunately, if the blood glucose has been equally high and low, then a normal HbA1c may be the result. This is why the patient’s own home blood testing record is important.Question 5 (1st and 4th Learning Outcome)When would you expect to find ketones in urine?Ketones may be found in the urine and blood of people with Type 1 diabetes who have insufficient insulin in their blood to control their blood glucose level and prevent the breakdown of body fats into ketones. Ketones can also be found in small quantities in the urine of people who have been fasting for a prolonged period of time.Question 6 (5th Learning Outcome)Jane weighs 70 kg and is 1.75 m tall. Nina weighs 70 kg and is 1.52 m tall. Who is at greater risk of CHD, based on their BMI?The equation to calculate BMI is:A BMI greater than 25 kg/m2 is a risk factor for CHD, so Nina has a higher risk than Jane.ConclusionThis course covered the annual review for people with diabetes. You have seen that even if someone feels they are in good health, they may still have risk factors that could increase the chances of getting diabetes-related complications. It is important to create a plan, which is agreed between the person with diabetes and the health professional, to show what actions need to be taken to reduce risk factors or maintain low risk.The diabetes annual review is an opportunity to check for factors that will increase a person's risk of developing diabetes complications, so they can address them before damage occurs. The idea is very much that ‘prevention is better than cure’. It is also an opportunity for the person with diabetes to get feedback on how well they are doing (and recognition if they are struggling with aspects of their condition).Every person with diabetes must have an annual diabetes review. It can be delivered at the hospital diabetes clinic, or for most people, by their local GP and practice nurse. The person with diabetes should not be a passive element in the process: they are supplying much of the information from their own monitoring and experience of living with the condition. They should have the results of the tests performed on them, and be given explanations about their meaning. They then have the information about how well they are managing their diabetes, and are able to make choices about any changes they may wish to make about their management.Studying this course will have built on your knowledge of diabetes and diabetes care systems, and the personal impact of having diabetes, as well as helped you to think about underlying risk factors for complications.Diabetes Control and Complications Trial Research Group (DCCT) (1993) ‘The effects of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus’, New England Journal of Medicine, 329 (14), pp. 977–986.National Institute for Health and Clinical Excellence (2002) Inherited Clinical Guideline H. Management of type 2 diabetes: Management of blood glucose, London, National Institute for Health and Clinical Excellence.UK Prospective Diabetes Study (UKPDS) (1998) ‘Group Intensive blood glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33)’, Lancet, 352, pp. 837–853.The content acknowledged below is Proprietary (see terms and conditions) and is used under licence.Grateful acknowledgement is made to the following sources for permission to reproduce material in this course:Course image: Michael Stern in Flickr made available under Creative Commons Attribution-ShareAlike 2.0 Licence.Figures 1, 4 right and left, 6a, 6b, 7b, 8 and 10: Mike Ford and DaveMustcroft/The Open University;Figure 2: Ed Young/Science Photo Library;Figure 3: Courtesy of Tracy Finnegan;Figure 4 middle, 5, 6c: 9a, 9b, 12a, 12b and 12c: Mike Levers/The Open University;Figure 11a: Yoav Levy/photolibrary.com;Figure 11b: Van Wynsberghe, D., Noback, C. R. and Carola, R. (1995) Human Anatomy and Physiology, 3rd edn, McGraw-Hill Inc© Mike Dodd.Don't miss out:If reading this text has inspired you to learn more, you may be interested in joining the millions of people who discover our free learning resources and qualifications by visiting The Open University - www.open.edu/openlearn/free-courses
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