Pattern management for glucose control
Is it time to look again at self monitoring in order to prevent the extremes of blood glucose levels for all diabetes patients? Practice Nurse looks at the evidence for effective pattern management
Much evidence points to the necessity to achieve relatively normal blood glucose control in order to prevent the long term complications of diabetes. With the growing emphasis on supported self-management as a means of managing diabetes, practice nurses have to have the skills, competence and confidence to effectively support and manage people on insulin therapy. Effective pattern management helps both patients and health care professionals to rapidly indentify emerging patterns and take effective action to re-establish glycaemic stability.
BACKGROUND
Diabetes is a growing and significant health problem. It is estimated that by 2025 the number of people with diabetes will grow from the current level of 2.9 million to 5 million across the UK.1 It is well recognised that people with diabetes have an increased risk of developing health complications and that they also have a significantly reduced life expectancy.2,3 It is estimated that 10 per cent of the total NHS budget is spent on diabetes, with the vast majority of this spend going towards the treatment of these complications.4 Research has shown that good control of diabetes by the maintenance of near normoglycaemia is crucial for the prevention of complications.5 Good glycaemic control is widely agreed to be fasting blood glucose levels of 4 — 7 mmol/l rising to 4 — 8.5 mmol/l two hours post prandially in order to achieve and maintain a glycated haemoglobin (HbA1c) level of 47 to 58 mmol/mol.6
HbA1c is the main tool for monitoring glycaemic control, but it does not provide us with useful information on daily glucose excursions. To achieve the day-to-day level of glycaemic control necessary for the prevention of complications, it is important to avoid the extremes of glycaemia, namely hypoglycaemia and hyperglycaemia, both of which have a detrimental outcome. Hypoglycaemia has been shown to lead to alteration of the electrical conductivity of the heart and additionally affects the epithelial lining of the blood vessels,7 in addition to the immediate dangers of loss of consciousness. High blood glucose levels cause short term problems that potentially hinder recovery from an acute illness or surgery, including the impairment of wound healing, increased risk of infection and fatigue.8
Clinical trials have demonstrated a direct link between high blood glucose levels and microvascular disease while conversely the achievement of good glycaemic control reduces the risk of macrovascular disease.9,10 This body of evidence has led to the development of current HbA1c targets. However, HbA1c accounts for less than 25% of the variation in risk of developing complications.11 Post prandial hyperglycaemia is now recognised as an independent risk factor for macrovascular disease.12,13
It is therefore important to manage daily excursions in blood glucose. Accurate and reliable information, achieved from self monitoring of blood glucose (SMBG), is vital.14 Information regarding fasting, pre prandial, post prandial hyperglycaemia and the immediate feedback for the detection and resolution of hypoglycaemia is needed to build a picture of daily glycaemic patterns. It is equally important that patients and health care professionals alike have the knowledge, confidence and ability to deal with the results obtained from SMBG.
It is widely agreed that SMBG is imperative in type 1 diabetes, but the picture is less clear for its use in type 2 diabetes. Some studies have indicated that SMBG has little impact on improving glycaemic control in this group.15-17 However, if the person with type 2 diabetes has the knowledge to monitor their blood glucose accurately, consistently uses SMBG in a way that allows for the identification on emerging patterns of glycaemic control, has the ability to appropriately make adjustments to their therapy and applies this skill consistently, then SMBG can have a significant benefit.18
In both type 1 and type 2 diabetes the use of SMBG can be a fundamental tool in the achievement of adequate glycaemic control for the purpose of the prevention of acute or longer term complications. However, this can only be the case if the information gained from SMBG is used in an appropriate way.
DEFINING PATTERN MANAGEMENT
Pattern management is defined as the systematic analysis of daily, weekly and longer term blood glucose values in order to make effectual medication, dietary or activity adjustments that will have a positive effect on blood glucose levels.
What does pattern management involve?
A pattern is a series of blood glucose results, taken at the same testing time each day, that are outside the parameters set for that individual. Pattern management involves being able to distinguish these emerging patterns, identify the possible cause, and if necessary make an alteration that will re-establish control. In order to do this successfully both the health care professional and the person with diabetes need to have a sound working knowledge of the factors that can influence glucose control. (Box 1)
Clinical aspects of pattern analysis
In order to optimise patient safety when advising on changes in medication or insulin doses that may be necessary to optimise blood glucose levels, the nurse has to be confident that the results given and recorded are as accurate as possible. A sound knowledge of factors that can affect meter accuracy is therefore imperative.
The storage of strips and effective cleaning of the finger prior to obtaining sample can both adversely affect the blood glucose value given by a meter. The haematocrit level can also greatly effect on the accuracy of reading obtained.19,20 Studies have shown that lower than normal haematocrit levels can overestimate the glucose value and higher than normal levels will give a falsely lower glucose result.21 I t is believed that the reason for the abnormal glucose values seen is due to the altered viscosity of blood directly relating to the abnormal hematocrit.22 Situations causing abnormal haematocrit levels that could adversely affect meter accuracy are seen in box 2.
FACTORS INFLUENCING BLOOD GLUCOSE LEVELS
The health care professional has to have a full understanding of the influence that food has on blood glucose levels. Such factors include the role of carbohydrates, the effect of combining carbohydrate with other food groups to slow the breakdown of the carbohydrate and delay or limit the subsequent rise in blood glucose level, and the effect of differing carbohydrate amounts consumed at the same mealtime on subsequent days. These factors can all affect the blood glucose level seen following the food intake.
If people are not adjusting their doses of insulin for specific carbohydrates amounts it is preferable that they have a consistent day to day carbohydrate meal plan.23
It is also important to have a full understanding of the action of different insulin preparations and diabetes medications in order to gain their optimum therapeutic effect. Meals and snacks can be taken to coordinate with the action profile of the medication.
Illness, stress and exercise can all have an impact on the blood glucose levels. Physical or psychological stress and illness cause a rise in counter regulatory hormones. These hormones (glucagon, norepinephrine, epinephrine, cortisol and growth hormone) increase insulin resistance and stimulate glucose release from the liver, whereas exercise increases glucose uptake by the muscles, lessens insulin resistance and potentially reduces blood glucose levels.
In people who inject insulin, the importance of regularly reviewing the injection technique and rotation of sites cannot be overestimated. Lipohypertrophy (fatty lumps at the injection sites), or inadvertently injecting into muscle due to incorrect needle length, can have a significant impact on insulin absorption and therefore blood glucose control.24
Many of the longer term complications of diabetes can have an adverse effect on glucose control. In advanced renal disease, for example, the length of action of medications and insulin can increase. As the kidneys are less able to filter out these medications, there is an accumulation of the drug and a resulting reduction in blood glucose levels can be seen.
ROLE OF THE PRACTICE NURSE
In diabetes care, the majority of patients are now routinely looked after in general practice. Managing patients on insulin therapy is therefore now a regular and fundamental role of the practice nurse. Effective management of these patients requires a level of competency, skill and confidence.25 Courses and local training programmes are available to educate nurses in the art of starting patients on insulin but the long term management of these patients requires additional skills and competency. The nurse needs the knowledge and ability to identify emerging patterns in daily glucose patterns and then to have the confidence to correctly advise on changes that may be indicated to re-establish a level of blood glucose control and stability.
The nurse has to have the confidence to support, educate and motivate the patient to make appropriate alterations to regimens that will positively affect control.
MOTIVATING PATIENTS TO TAKE PART IN PATTERN MANAGEMENT
It is often stated that the reason people do not manage to identify patterns in their daily results, or to make alterations to their medications even if a pattern has been successfully identified, is that they do not have the knowledge and confidence to make a change. The tendency is for people to take immediate action to treat 'one off' results and rarely look for emerging patterns. They often do not recognise that they are regularly having results outside of their target range at the same time of day several days of the week. The fear that they may cause a 'hypo,' or previously-made changes to their treatment that did not have the desired result, deter them from making any adjustments to treatment now. The nurse needs to work with the person to instil confidence and build the knowledge necessary for them to take control once again. The education she provides must take account of past experiences, learning preferences and physical, sensory and cognitive abilities. This is likely to mean frequent, shorter education and support sessions with repeated demonstrations of correct injection and monitoring technique.23
To help with this, meters today can display the data in different formats. Each person will have a preferred way of visualising their data, whether it is in the form of a table, chart or graph. The important element is that the data, however it is displayed, means something to the person interpreting it. Meters are now available that also allow for meal timings and exercise to be recorded. This information allows for successful interpretation of the results and the identification of emerging patterns. The health care professional can then support the patient to know what needs to change to control this pattern and re-establish glycaemic stability.
Making effective changes in response to SMBG results can help to maintain good daily glycaemic control. This has a positive impact on HbA1c. Being able to control or respond to glucose excursions in a timely manner to improve long term glucose control without causing any further issues in regard of hypoglycaemia or hyperglycaemia is invaluable.
CONCLUSION
Poor diabetes control leads to debilitating and costly long term complications, costly both in terms of the psychological effect on individuals and in financial terms to the health economy. Good glycaemic control has been proven to prevent both micro and macro vascular complication. Long term glycaemic control is assessed using the HbA1c test and this gives an excellent indication of glycaemic control over the previous 8-12 weeks. However, HbA1c tests are unable to highlight daily glucose excursions that can result in a sub-optimal HbA1c result and directly lead to the development of these complications.
Pattern management has a key role to play in the achievement of improved daily glucose levels in individuals. The success of pattern management relies on the ability to understand factors relating to glycaemic control, the skill to identify emerging patterns and the knowledge to make treatment adjustments in a timely manner to re-establish good control.
The author was paid an honorarium for the preparation of this article by LifeScan, part of the Johnson & Johnson family of companies
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