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Case studies
Blood ketone monitoring in type 1 diabetes: A proactive approach to reducing DKA hospital admissions
Caroline Dunstan, DSN Lead, Cornwall and Isles of Scilly Primary Care Trust,
Diabetes and Endocrine Centre, Royal Cornwall Hospital, Treliske.
This supplement and the study described within it were sponsored by Abbott Diabetes Care.
Introduction
Diabetic ketoacidosis (DKA) is a serious and potentially fatal complication of type 1 diabetes. DKA admissions in England have risen steadily in recent years, which places an increasingly significant financial burden on the NHS. Healthcare professionals have a responsibility to actively seek effective ways to reduce the incidence of DKA and the cost associated with hospital admissions. Given that DKA may be preventable with frequent monitoring of glucose and ketone levels, we initiated a proactive ketone management programme in Cornwall in 2006. Four years on, our programme has substantially reduced DKA admissions in the county and appears to have increased the confidence of people in managing potential diabetic emergencies themselves. Here, we present the motivation behind our work, details of the programme and our key findings.
| Box 1. Advice on when to initiate blood ketone testing. |
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| Fasting blood glucose level | What to do | ||
| A little bit high (7-10 mmol/L) |
Continue with your usual insulin and blood glucose testing. Contact your diabetes team to discuss your levels if this is often your range. | ||
| High (10-16 mmol/L) |
Consider taking extra insulin. Check glucose every 2-4 h until it is below 10 mmol/L. If it goes on rising or you feel ill, check ketones. Contact your diabetes team if this is often your range. | ||
| Very high (above 16 mmol/L) |
Check ketones and follow given advice. Continue checking blood glucose as well as ketone levels. |
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Blood ketone testing plays an important role in monitoring the resolution of diabetic ketoacidosis (DKA) (Wallace and Matthews, 2004) and predicting its onset (Harris et al, 2004).
DKA, a serious complication of type 1 diabetes (Laffel et al, 2006), is a result of absolute or relative insulin deficiency in combination with metabolic derangement, leading to increased levels of ketone bodies in the blood, known as ketonaemia (Wallace and Matthews, 2004).
About a quarter of DKA cases occur in people with newly presenting type 1 diabetes (Department of Health [DH], 2001). In those with existing diabetes, insulin omission, infection or other acute illness can immediately trigger DKA (DH, 2001) and this may put them in a life-threatening situation. People with DKA require highintensity nursing on a one-to-one basis, usually achieved in a high dependency unit or an intensive care unit (Holt and Kumar, 2010).
Managing an increasing burden
The numbers of DKA admissions in England have risen steadily in recent years (Diabetes UK, 2010), which places an increasingly significant financial burden on the NHS. Healthcare professionals working in diabetes should, therefore, actively seek effective ways to reduce the incidence of DKA and the cost associated with hospital admissions.
How can we achieve this? Given that DKA may be preventable with frequent monitoring of glycaemia and ketosis, along with timely supplemental insulin (Laffel et al, 2006), it seems that changes in monitoring practices and related educational initiatives will play a part.
For many people with type 1 diabetes, self-monitoring of blood glucose (SMBG) is an integral part of the day-to-day management of their condition. However, the degree of hyperglycaemia alone is not a reliable index for the severity of DKA (Holt and Kumar, 2010). Ketone levels will also need to be measured.
Urine or blood ketone testing?
Although most commonly used in clinical practice, urine dipstick tests can give false-positives when the test strips are exposed to air for long periods (Goldstein, 1995). Also, from a practical point of view, it can be difficult to obtain urine samples from severely dehydrated patients (Wallace and Matthews, 2004), or from children. Indeed, one of the widest known axioms of caring for a young child with diabetes is "you can lead a child to ketone strips, but you can't make him pee"!
In contrast, blood ketone tests (Figure 1) can more accurately and conveniently monitor ketonaemia (Wallace and Matthews, 2004). Furthermore, "real time" results are available by directly measuring blood ketone levels, whereas urine ketone changes often lag behind blood ketone changes by 2-4 h (Kysh and Fazakerley, 2007). By using two different strips, glucose and ketone levels can be measured in the blood from the same finger prick test.
Based on compelling evidence, the latest Joint British Diabetes Societies (JBDS) guidelines (JBDS, 2010) state that "measurement of blood ketones now represents best practice in monitoring the response to treatment". The group recommends "provision of handheld ketone meters and education on management of ketonaemia" to people with a history of DKA, as well as staff training "in the use of blood glucose and ketone meters".
The American Diabetes Association (ADA) (Wallace and Matthews, 2004) and the British Society of Paediatric Endocrinology and Diabetes (BSPED) (Edge, 2009) also recommend the use of blood ketone tests, rather than urine ketone tests, for diagnosis and monitoring of DKA.
Blood ketone monitoring and education
Despite these recommendations, blood ketone testing has not yet been widely adopted in the UK. Here in Cornwall, we have been trying to formalise the use of blood ketone tests in preventing DKA admissions since 2006.
The author became aware of the high incidence of DKA in Cornwall when data suggested that there were 248 admissions for DKA in the county in 2005/6 (Kysh and Fazakerley, 2007).
The problem was compounded by the fact that Cornwall has a geographically scattered population and it can take many people over 45 min to travel to the nearest hospital in an emergency. There appeared to be an urgent need for proactive education and improved self-care in the population with type 1 diabetes.
With this in mind, we initiated a programme of structured education on preventing DKA that incorporates blood ketone monitoring. The programme was trailed initially by the author and a second DSN (Kysh and Fazakerley, 2007), and then introduced to the remaining seven DSNs in the county. It is now being rolled out across Cornwall to a number of practice nurses with a particular interest in diabetes. Ultimately, we aim to extend the programme to everyone in Cornwall with type 1 diabetes. As such, it is being offered to all new cases of type 1 diabetes at the point of diagnosis, and to people with existing type 1 diabetes either at their scheduled diabetes review or at their first contact with a healthcare professional involved in the scheme.
In the initial pilot programme in a small area of Cornwall involving 27 people with existing type 1 diabetes and a history of DKA, we saw a reduction of 45% in the number of hospital admissions 3 months after the introduction of the ketone management programme (Kysh and Fazakerley, 2007).
This encouraging result prompted us to carry out further study in a larger population. Between 2005 and 2006, we enrolled 147 people with type 1 diabetes into the programme at Royal Cornwall Hospitals Trust and Plymouth NHS Trust. We excluded those unable to self test or comprehend educational materials, and those who have severe nonadherence with insulin treatment. Among the 147 candidates, 96 had existing type 1 diabetes with a history of DKA and 51 were newly diagnosed with type 1 diabetes upon admission with DKA. The latter were not taken into account in the calculation of the difference in DKA admission rates before and after the introduction of the programme.
The remaining candidates were offered a dual glucose and ketone testing meter (FreeStyle Optium, Abbott Diabetes Care, Maidenhead), if not already using the device. We encouraged them to carry the meter at all times because it would be difficult to predict when they would need to test for blood ketones.
In general, we gave them the following advice on when to test their blood ketone levels.
- When prompted by the FreeStyle Optium meter.
- Every 2-4 h when they suffered any acute illness, including an infection, a raised temperature or vomiting,or when they experienced any of the symptoms of DKA, including dehydration, blurred vision, breathing difficulties, tiredness, and confusion.
- When capillary blood glucose levels exceeded 16 mmol/L.
They were also given a personalised care plan suggesting when to initiate ketone testing based on self-monitored blood glucose levels (Box 1). In addition to this care plan, we gave these candidates a "traffic light" system protocol outlining guidelines on use of additional insulin according to blood ketone levels (Box 2). We hoped that these practical tools would increase the confidence of people in self-monitoring their blood ketones, which is crucial in successful management of DKA.
One year later, the outcome was positive. With the assistance of blood ketone testing, the number of DKA hospital admissions was reduced by 23%, down from 126 in 2005/6 to 97 in 2007/8 (Figure 2). Based on a cost savings model developed by Abbott Diabetes Care, if all people with type 1 diabetes falling within the Cornwall and Isles of Scilly Primary Care Trust were offered one box of ketone test strips per year, a 23% reduction in DKA hospital admissions would produce potential annual savings of ÃÃÃÃÃÃã105,226 in this region.
Furthermore, anecdotal feedback from individuals involved in this study suggests that, although the advice we provide on ketone management may seem prescriptive, many of them actually appreciate being directed, especially at times when they feel vulnerable for fear of acute illness.
A formalised protocol such as this may increase their confidence in appropriately and effectively managing the disease themselves. It is worth noting that three of the four candidates who were at high risk of DKA and had frequent admissions in 2005/6 were not admitted to hospital for DKA at all in 2007/8 as a result of carefully monitoring their blood ketone levels and following the advice we had given them.
Among the people who had benefited significantly from our programme was Jane (name changed for confidentiality). Aged 22, she was enrolled at the end of 2006. In the first 7 months, Jane had only one DKA admission, compared with seven during 2004/6. As her confidence grew, she was able to manage her condition completely independently from July 2006, without calling the DSNs for advice when feeling ill.
This was life-changing for Jane, who was diagnosed with type 1 diabetes at the age of 13 and had had frequent demand for professional care for a long time. Jane said: "I used to feel inadequate in managing my diabetes and have always considered being hospitalised as a failure. But now I feel more emotionally in control. Rather than waiting for the inevitable to happen, I am able to monitor my ketone levels independently and I know what to do when the levels are getting high. This is liberating."
I used to feel inadequate in managing my diabetes, but now I feel more emotionally in control.
Closing remarks
"Empowering people with diabetes" is a key component of the National Service Framework for Diabetes (DH, 2001). To help people with diabetes care for themselves, healthcare professionals need to know how to support them in appropriately managing potentially life-threatening DKA. We have demonstrated that it is possible to achieve a marked decrease in DKA admissions through a proactive educational programme incorporating blood ketone monitoring. We hope that our programme will continue to provide active support to people with type 1 diabetes, help prevent the onset of DKA, reduce hospital admissions, free up financial resources, and eventually benefit the wider community.
Diabetes UK (2010) More than 3,000 emergency hospital admissions a year for children with diabetes. Available at: http://tiny.cc/p88so (accessed 07.06.2010)
Department of Health (DH; 2001) National Service Framework for Diabetes: Standards. DH, London
Edge JA (2009) BSPED recommended DKA guidelines 2009: Guidelines for the management of diabetic ketoacidosis. The British Society of Paediatric Endocrinology and Diabetes, Oxford. Available at: http://www.bsped.org.uk/professional/guidelines (accessed 07.06.2010)
Goldstein DE, Little RR, Lorenz RA et al (1995) Tests of glycemia diabetes. Diabetes Care 18: 896-909
Harris S, Syed RNH, Hillson R (2004) Near patient blood ketone measurements and their utility in predicting diabetic ketoacidosis. Diabetic Medicine 22: 221-4
Holt T, Kumar S (2010) Chapter 7: Hyperglycaemic emergencies and management of diabetes in hospital. In: Holt T, Kumar S (eds) ABC of Diabetes (sixth edition). Blackwell Publishing, Oxford, 31-3
Joint British Diabetes Societies (JBDS; 2010) The Management of Diabetic Ketoacidosis in Adults. JBDS Inpatient Group, London. Available at: http://tiny. cc/9wtnw (accessed 23.06.2010)
Kysh C, Fazakerley K (2007) Ketone testing for diabetes management: A pilot programme of proactive education. Journal of Diabetes Nursing 11(Suppl): S1-4
Laffel LM, Wentzell K, Loughlin C et al (2006) Sick day management using blood 3-hydroxybutyrate (3-OHB) compared with urine ketone monitoring reduces hospital visits in young people with T1DM: a randomized clinical trial. Diabetic Medicine 23: 278-84
Wallace TM, Matthews DR (2004) Recent advances in the monitoring and management of diabetic ketoacidosis. Q J Med 97: 773-80
Wallace TM, Meston NM, Gardner SG et al (2001) The hospital and home use of a 30-second handheld blood ketone meter: guidelines for clinical practice. Diabetic Medicine 18: 640-5
| Box 2. Local guidelines on blood ketone monitoring. |
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| Ketone levels | What to do | ||
| Below 0.6 mmol/L | This level is normal - carry on with your usual blood glucose testing. | ||
| 0.6-1.5 mmol/L | Test your blood glucose after 1 h. Continue regular insulin regimen. Consider increasing insulin after 1 h. If blood glucose and ketones are falling, retest hourly until ketones are below 1.1 mmol/L. | ||
| 1.5-3 mmol/L | Take additional short- or rapid-acting insulin. If you do not have this type of insulin,
use your usual premix insulin. Take the amount shown below or take one-fifth of your
total daily dose. If this is above 10 units, only take 10 units.
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| Above 3 mmol/L and/or continued vomiting and unable to tolerate fluids |
SEEK SPECIALIST ADVICE IMMEDIATELY Take additional short- or rapid-acting insulin. If you do not have this type of insulin, and unable to tolerate fluids use your usual premix insulin. Take the amount shown below or one-fifth of your total daily dose. If this is above 10 units, only take 10 units.
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