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Self-monitoring of blood glucose in type 2 diabetes

As the prevalence of type 2 diabetes continues to increase, nurses are seeing more patients than ever with the disease. Self-management is critical with a chronic disease, and self-monitoring of blood glucose can significantly help some patients manage their condition. But research shows that in order for this to be successful, patients need ongoing support from healthcare professionals

Nicola O'Connell
BA(Hons)
Freelance Healthcare
and Medical Writer
London

Type 2 diabetes is becoming an increasingly major burden within developed countries; in the UK, the prevalence of type 2 diabetes rose by more than 50% between 1991 and 2001.(1) The complications of diabetes, which include cardiovascular disease, kidney failure and stroke, can be serious and costly; indeed much of the expenditure on diabetes relates to the management of complications.
Improving the management of blood glucose to help maintain control and reduce the complications of diabetes remains a major challenge for all healthcare professionals, and in particular nurses may be able to provide a key role in addressing patients' concerns and questions. In its report, entitled Diabetes: State of the Nations, Diabetes UK stated that two in five adults and more than four in five children and young adults have poor blood glucose management that puts them at risk of complications.(2)
Self-management in diabetes is recognised as key to good diabetic control. The Diabetes UK report emphasised that self-care is the cornerstone of diabetes care "as 95% of managing the condition is self-care". The report also stated that glucose control is central to the self-management of diabetes. Diabetes UK believes that people with diabetes should have access to home blood glucose monitoring based on individual clinical need and informed consent. "People with diabetes value being able to monitor their blood glucose levels for themselves as it enables them to better manage their diabetes, help prevent devastating and potentially costly complications, and take control of their own diabetes," the charity has said.(3)
The benefits of self-monitoring of blood glucose monitoring (SMBG) in the management of type 2 diabetes have been debated over some years, yet guidelines generally advocate its use. The International Diabetes Federation has drawn up guidelines to support the use of SMBG in type 2 diabetes, and NICE states that "self-monitoring can be used in conjunction with appropriate therapy as part of integrated self-care."(4,5 )Furthermore, the National Service Framework for Diabetes (Standard 4) states that "all adults with diabetes will receive high-quality care throughout their lifetime, including support to optimise the control of their blood glucose, blood pressure and other risk factors for developing complications of diabetes."(6)
Despite the wealth of guidance, the clinical benefits of SMBG among patients with type 2 diabetes have not been fully evaluated (the evidence for patients with type 1 diabetes is stronger). In 2002, a Medical Research Council Bulletin briefing claimed that there was not enough evidence to support SMBG in type 2 diabetes.(7) Since then, however, new data have emerged in support of SMBG. The multicentre RetrOlective Study, "Self-monitoring of blood glucose and outcome in people with type 2 Diabetes (ROSSO)", shows that people with type 2 diabetes who self-monitor have a lower risk of death and complications.(8) The ROSSO study followed 3,268 patients from diagnosis of type 2 diabetes between 1995 and 1999 until the end of 2003. Investigators noted that the total rate of nonfatal events, micro- and macrovascular, was lower in the SMGB group than in the non-SMBG group (7.2% versus 10.4%), and a similar difference was found in the rate of fatal events (2.7% versus 4.6%).
The study concludes that after adjustment for  potential cofounders, hazard ratio indicated that SMBG was associated with a 32% reduction in combined nonfatal endpoints and a 51% reduction in mortality over the observation period. Nonfatal endpoints included myocardial infarction, stroke, foot amputation, blindness and endstage renal failure; fatal endpoints were all-cause mortality.
In 2005 the Cochrane Collaboration highlighted the role of SMBG in people with type 2 diabetes.(9) The review included six randomised controlled trials, two of which reported a significant lowering effect of self-monitoring of blood glucose on HbA1c. The Canadian Diabetes Association also refers to an observational study showing that SMBG is associated with lower concentrations of HbA1c in diabetic patients not treated with insulin.10

Lack of patient support and education
Nevertheless, scepticism remains among healthcare professionals about the role of SMBG - perhaps partly due to the lack of long-term trials specifically looking at patient-related outcomes such as quality of life, wellbeing and patient satisfaction, and also partially due to a belief that patients will not benefit from SMBG because they will not do anything different in accordance with their results. Yet this inherent belief may, in turn, be the one key thing that is stopping patients from not benefiting more from SMBG. For example, if nurses can demonstrate a positive attitude towards the role of SMBG, this could provide patients with the encouragement that they need.
A longitudinal, qualitative study recently published in the BMJ set out to assess the views of patients with newly-diagnosed type 2 diabetes about SMBG.(11) The study found that healthcare professionals' input was key to how patients perceived the role of SMBG. The study showed that patients were in fact self-monitoring for their healthcare professionals' benefit, rather than their own - even though the patients claimed that the professionals did not show interest in the readings. Indeed, healthcare providers' lack of interest was the reason that patients gave for discontinuing self-monitoring, while reassurance was a key reason for continuing.
Lack of patient education, it appears, certainly contributed to the problems with self-monitoring in this study. While participants generally received initial education about how to use glucose meters, none reported receiving additional education about self-monitoring after the first year following diagnosis. The study concluded that the role of health professionals is crucial, particularly as patients seem to need more guidance about interpreting and responding to readings. Education about SMBG should be ongoing and tailored to patients' specific needs, and patients need to be aware of the connections between HbA1c and SMBG, the report said.
Jo Head, lead clinical nurse specialist in diabetes at the Marlfied Cottage Diabetes Education Centre, Royal Hampshire County, Winchester, believes that this education, which can be provided by nurses, is critical to patients' success with SMBG. "For blood glucose monitoring to be of value, individuals must be taught how to self-monitor, and they need to have a perception of why they are doing it and what action they may need to take with the result," she says. "Patients need to have the opportunity to open up and ask any questions or discuss concerns, and strategies must be developed on a person-to-person basis."

Difficulties with blood glucose meters
Dislike of using blood glucose meters, or difficulties associated with using them, is another reason for patients' problems with SMBG. Sometimes patients complain that SMBG serves as a constant reminder that they have diabetes, or that they find SMBG painful, inconvenient or embarrassing. "All of this can be discussed with the patient, along with practical advice on testing," says Jo Butler, consultant diabetes nurse, Wandsworth PCT. "For instance, to minimise pain, patients can be advised to prick the side of the fingers and to avoid the first finger and the thumb."
Difficulties using meters is not uncommon - particularly when it comes to meter coding. The MHRA advises that inaccurate meter coding can lead to inaccuracies in blood glucose measurement of up to 4 mmol/l.12 A study published earlier this year found that for certain miscoded blood glucose meters, the probability of insulin error of plus or minus two units of insulin could be as high as 50%, compared with 7.1% for correctly manually coded meters.(13) For the meters that do not require manual coding, the probability of plus or minus one unit and plus or minus two units of insulin could be 35.4% and 1.4% respectively. A previous study, published in 2003, found that approximately 16% of people failed to properly manually code their blood glucose meters to the lot of test strips being used.(14)
Miscoding can occur for a number of reasons, such as accidentally pushing a wrong button, or forgetting to insert a new code or strip into the meter when using a new bottle of test strips. "Manual coding can be confusing for patients, and not surprisingly errors are made," says Ms Butler. "The consequences can be serious because insulin dose errors may put some patients at greater risk of hypoglycaemia, and in the longer term, inaccurate readings can mask poor glycaemic control, which is associated with the risk of serious complications."
Not all SMBG meters currently available require manual coding, potentially offering a solution to those patients who have difficulties. Says Ms Butler: "A system that does not require coding is appealing to patients - and therefore has the potential to improve compliance - and is also of significant clinical benefit."

Conclusion
Guidance strongly favours SMBG among patients with type 2 diabetes. A lack of conclusive evidence of its benefit has caused wide debate, but more recent studies have demonstrated supporting data. There is a major opportunity for nurses to provide patient education and ongoing support, which may be critical to the success of SMBG. Patients need to have clear objectives; they also need precise instruction on how to use blood glucose meters and how to interpret the results. Manual coding of meters can be problematic for some patients, leading to inaccuracies, so for these patients a system that does not require manual coding may be most appropriate. Healthcare professionals need to work in partnership with patients to try to establish a commitment to SMBG (the required frequency of SMBG varies among patients, but individual plans can be agreed). Only when such action is taken can patients and healthcare professionals benefit most from SMBG and indeed its longer-term benefits, such as reducing serious complications.

References

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  2. Diabetes UK. Diabetes: state of the nations. 2006. Available from: http://www.diabetes.org.uk/Documents/Reports/SOTN2006_full.pdf
  3. Diabetes UK. Home monitoring of blood glucose levels. Position statement. London: Diabetes UK; 2003. Available from: http://www.diabetes.org.uk/About_us/Our_Views/Position_statements/Home_m...
  4. International Diabetes Federation. Clinical guidelines task force. Global guidelines for type 2 diabetes. Brussels: IDF; 2005.
  5. NICE. Management of type 2 diabetes: management of blood glucose. London: NICE; 2002.
  6. Department of Health. National Service Framework for Diabetes: Standards. Standard 4: clinical care of adults with diabetes. London: DH; 2001.
  7. National Prescribing Centre. When and how should patients with diabetes mellitus test blood glucose. MeReC Briefing. London: MRC; 2002.
  8. Martin S, Schneider B, Heinemann L, et al. Self-monitoring of blood glucose in type 2 diabetes and long-term outcome: an epidemiological cohort study. Diabetologia 2006;49:271-8.
  9. Welschen LMC, Bloemendal E, Nijpels G, et al. Self-monitoring of blood glucose in patients with type 2 diabetes mellitus who are not using insulin. Cochrane Library 2005;4.
  10. Canadian Diabetes Association. Clinical practice guidelines. Toronto: CDA; 2003. Available from: http://www.diabetes.ca/cpg2003
  11. Peel E, Douglas M, Lawton J. Self-monitoring of blood glucose in type 2 diabetes: longitudinal qualitative study of patients' perspectives. BMJ 2007;335:493.
  12. Department of Health. Evaluation. Best choice, best practice. A guide to blood glucose meters on the UK market. London: DH;2005.
  13. Raine CH, Schrock LE, Edelman SV, et al. Significant insulin dose errors may occur if blood glucose results are obtained from miscoded meters. J Diabetes Sci Technol 2007;2:205-10.
  14. Raine CH. Self-monitored blood glucose: a common pitfall. Endocr Pract 2003;9:137-9.