best practice 10, December 2007: Self monitoring in diabetes

Self monitoring in DIABETES

Full colour PDF of the pages as they appeared in ‘best practice’.

Self monitoring of blood glucose is an important component of diabetes management for some people. But, which people?

Any component of a treatment plan that is both invasive and expensive needs to result in an improved clinical outcome.¹ Gathering information about blood glucose levels is only useful when it can be used to improve clinical outcomes.

Clinical outcomes in diabetes are improved when glycaemic control is improved. Measurement of the concentration of glycated haemoglobin (HbA1c) is the most appropriate and accurate way to monitor glycaemic control. When then, does self monitoring of blood glucose provide additional benefit?

Type 1 Diabetes

Self monitoring of blood glucose (SMBG) is mandatory for people with type 1 diabetes. The information gained is essential for patients to adjust the type and amount of food and exercise, document hypo and hyperglycaemia and select appropriate dosages of insulin. People with type 1 diabetes usually test three to four times a day and are educated to act on the result to bring about improved control (i.e. a lower HbA1c result).

Type 2 Diabetes

Self monitoring is required for people with type 2 diabetes on insulin

Advice regarding the use of SMBG for people with type 2 diabetes treated with insulin is essentially the same as for people with type 1 diabetes. These people however, may be on insulin regimens with less frequent dosing, and so may only need to test twice a day.

Advice for people with type 2 diabetes who are not using insulin needs individual consideration (includes those on oral medication)

There is no doubt that for the vast majority of people with diabetes, measurement of the concentration of glycated haemoglobin (HbA1c) remains the most appropriate and accurate way to monitor glycaemic control.

Evidence of benefit for SMBG in non-insulin treated type 2 diabetes

There is now an abundance of published research in this area. However the designs of the studies, the outcomes and ultimately the conclusions reached, have varied widely.² There is still a lack of consensus.^3,4 A conclusion reached in a recent commentary article was that for people with non-insulin treated type 2 diabetes, SMBG “is an expensive and popular procedure without an evidence base”.⁵ The author suggests that the only way to answer the question of whether to advocate routine SBMG would be through “properly designed, randomised clinical trials.”

Do the guidelines help us?

The current New Zealand guideline states that “self-monitoring of blood glucose is well-established in clinical practice, but the literature in this area is limited and difficult to assess”.⁶ The recommendation is that SMBG “should be considered in conjunction with appropriate therapy as a part of integrated self-care. The purpose of blood glucose self-monitoring should be clear and agreed with the person with diabetes.” A similar recommendation is included in the NICE guideline.⁷ However, a new draft of this guideline is under consultation at present.⁸

When does SMBG produce benefit for people with non-insulin type 2 diabetes?

The key message is that the aim of using SMBG is to improve glycaemic control, i.e. a lower HbA1c, and to ultimately reduce long term complications. Measuring blood glucose gives immediate information for the patient, but to give any benefit, this information must be acted upon.⁹

If HbA1c is already satisfactory without SMBG, adding it may not be associated with any further improvement.²

Therapeutic benefit is more likely to be obtained when:

There are special circumstances such as new diagnosis, starting or changing medication, illness, pregnancy and frequent hypoglycaemia¹⁰
The patient knows how and when to test and how to interpret or act on the results²
Patient education is individually tailored and ongoing¹¹
Patients are “sufficiently literate and numerate”¹⁰
Patients are motivated to make changes to diet or lifestyle^2,10
A clear goal is negotiated and agreed with patients¹¹
There is an understanding of the relationship between SMBG and HbA1c results¹¹

When used appropriately, SMBG can increase disease awareness and compliance¹⁰, it can empower^9,12 and reassure.¹¹

Conversely, the continual reminder of less than ideal control can lead to uncertainty, frustration, guilt and high levels of anxiety.^9,11 If GPs and practice nurses take little notice of self monitoring results and don’t use the readings as a chance for further education, it tends to reinforce the idea that test results are not important.¹¹ The patient will often become discouraged and lose motivation. GPs can end up spending a lot of time dealing with the anxiety arising from unexpected or poor results.

In patients who are receiving no benefit from SMBG, it is appropriate to stop.

The recent Diabetes Glycaemic Education and Monitoring (DiGEM) trial has concluded that “routine self monitoring of blood glucose for patients with reasonably controlled non-insulin treated type 2 diabetes seems to offer, at best, small advantages, is not well accepted, and the cost, effort and time involved in the procedures may be better directed to supporting other health related behaviours.”¹³ It is thought that studies such as this may encourage clinicians to talk to their patients about the usefulness of SMBG and give them “confidence to discontinue it if it is providing no benefit.”¹⁴

A pragmatic approach to the use of SMBG is recommended

If we are faced then with contradictory evidence and very broad recommendations, how do we make choices that will benefit our patients? The decision comes down to an individual patient level and relies upon the doctor and patient reaching agreement on the best course of action.

Andrew Moore, the editor of Bandolier, has been involved in a systematic review of the current evidence.¹⁰ He states that:

“It is sobering to remember that where doctors make their own decisions, the results have been terrific, especially in clinical outcomes with major consequence. They did it by deciding which patients with type 2 diabetes would benefit from self-monitoring and prescribing self-monitoring in those patients. Simple, really”.¹⁶

The issue of cost

Healthcare providers worldwide are struggling with the difficulties of who should get the healthcare dollars. A huge multi-billion dollar industry has developed to supply meters and strips and there is ongoing spending, with companies trying to produce increasingly fast and easy to use devices.¹⁵

The largest group of people using SMBG are those with non-insulin treated type 2 diabetes. The routine use of SMBG in this group can have a major cost impact and the expense can be justified only if it leads to savings in the future.¹⁵

Who to test and why to test have become major issues. In the United Kingdom, some primary care organisations now restrict access to blood testing strips causing debate between doctors, patients and suppliers. Diabetes UK (a charity for people with diabetes) has launched a national online campaign to try and reintroduce unrestricted access to home blood glucose testing equipment.³ Similar financial dilemmas face those working in primary health care in New Zealand.