22nd February 2011
A study has found that a structured self-monitoring of blood glucose intervention package improved glycaemic control compared with enhanced usual care in patients with poorly controlled type 2 diabetes not treated with insulin. However the difference in HbA1c (0.3%) between the groups may not be clinically significant.
Level of evidence:
Level 2 (limited quality patient-oriented evidence) according to the SORT criteria.
Quality, Innovation, Productivity and Prevention (QIPP): Medicines Use and Procurement recommends that, where appropriate, local use of self-monitoring of blood glucose (SMBG) in type 2 diabetes should be revised to ensure that it is in line with NICE guidance. NICE recommends that SMBG is appropriate in some people with type 2 diabetes, including those on insulin therapy and during intercurrent illness or medication and lifestyle changes. However, SMBG should only be used if it is going to be an integral part of the patients’ self-management education, and the continued benefit of self-monitoring should be assessed in a structured way each year. For many patients, attention and resources may be better directed to interventions likely to make a difference to their symptoms and cardiovascular risk. These include support and advice around nutrition, exercise, smoking cessation, and foot care, together with control of blood pressure and cholesterol.
What is the background to this?
For those people on insulin therapy who are adjusting their doses on the basis of their blood glucose, there is no debate about the necessity for self-monitoring. However, the usefulness of self-monitoring in patients treated with lifestyle interventions or oral agents is debatable.
This 12-month study was designed to investigate the effects of a comprehensive, structured SMBG intervention package (that encourages patients and physicians to work together to collect, interpret, and appropriately use SMBG data, collected over three consecutive days at least quarterly) compared with enhanced usual care (including quarterly clinic visits focussing on diabetes management, and free blood glucose meters and strips). The study included 483 poorly controlled (mean HbA1c 8.9%) type 2 diabetic patients not taking insulin from 34 primary care practices in the US. Practices were randomised to an active control group with enhanced usual care or a structured testing group with enhanced usual care and at least quarterly use of structured SMBG. The primary endpoint was HbA1c at 12 months.
What does this study claim?
The study found that HbA1c improved in both groups. Structured SMBG was statistically significantly more effective than enhanced usual care alone (mean reduction in HbA1c 1.2% vs. 0.9%, respectively, P=0.04). However, it is unclear whether the difference in HbA1c between the groups, 0.3%, is clinically significant (see below).
Significantly more patients in the structured SMBG control group received a treatment change recommendation at the month 1 visit, compared with the active control group, regardless of the patient’s baseline HbA1c (75.5% vs. 28.0%, respectively, P<0.0001). The authors conclude this suggests that when patients bring structured SMBG information to clinic visits, and when physicians know how to interpret and respond to SMBG information, timely and appropriate treatment changes are more likely to occur than in cases in which structured SMBG data are not available.
This study is interesting in that it shows glycaemic control in type 2 diabetes can be improved with an intensive package of care which may include SMBG. The authors suggest that patients and physicians can use SMBG data appropriately and effectively to reduce HbA1c and make timely treatment changes in poorly controlled patients with type 2 diabetes not treated with insulin when there is a well-defined testing protocol, a tool for organising the data, and the knowledge to interpret the data. However, the results of this study need to be viewed alongside those of other studies, and in the context of whether a change in HbA1c of 0.3% is clinically significant and enough to justify the additional resources needed to provide the intervention.
A recent HTA report carried out a systematic review of 30 randomised controlled trials of SMBG in type 2 diabetes, few of which were high quality. This concluded that SMBG is of limited clinical effectiveness in improving glycaemic control in people with type 2 diabetes on oral agents, or being treated with diet alone, and is unlikely to be cost-effective. Statistically significant reductions in HbA1c of about 0.2% were seen with SMBG, but this was not considered clinically significant as it was below 0.5%, the change in HbA1c level usually considered clinically significant.
The HTA report goes on to state that SMBG can be expected to lead to improved glycaemic control only in the context of appropriate education – both for patients and healthcare professionals – on how to respond to the readings, in terms of lifestyle and treatment adjustment. It may be more effective if patients are able to self-adjust drug treatment.
In the HTA authors’ opinion, at a time when funds are scarce, the case for investment in SMBG in patients with type 2 diabetes who are not treated with insulin, is not proven. Further research is required on the type of education and feedback that are most helpful, characteristics of patients benefiting most from SMBG, optimal timing and frequency of SMBG, and the circumstances under which SMBG causes anxiety and/or depression. It is unclear whether the provision of a comprehensive, structured SMBG intervention package such as that used in this US study would be cost-effective. For many non-insulin treated patients with type 2 diabetes, attention and resources may be better directed to interventions likely to make a difference to their symptoms and cardiovascular risk. These include support and advice around nutrition, exercise, smoking cessation, foot care, together with blood pressure and cholesterol control.
A small qualitative study in 18 patients with type 2 diabetes found that SMBG decreased over time, informed by the perceived disinterest of health professionals towards it. In addition, patients found the results difficult to interpret and act on, with few using SMBG to guide and maintain changes in their lifestyle or behaviour. The authors concluded that education about blood glucose should be explicit, goal oriented, tailored to individual needs, and on a continuous basis.
NICE recommends that SMBG is appropriate in some people with type 2 diabetes, including those on insulin therapy and during intercurrent illness or medication and lifestyle changes. However, SMBG should only be used if it is going to be an integral part of the patients’ self-management education, and the continued benefit of self-monitoring should be assessed in a structured way each year.
The NHS Diabetes Factsheet: Glucose Self-Monitoring in Diabetes states that people with type 1 diabetes and people with type 2 diabetes who use insulin should be monitoring blood glucose levels as part of their self-management programmes. In addition, it makes several recommendations regarding non-insulin treated patients with type 2 diabetes:
- SMBG with appropriate structured education should be available to people receiving sulphonylurea treatment to identify hypoglycaemic episodes
- In keeping with the recommendations contained within NICE Clinical Guideline CG87, SMBG should only be provided routinely to people with type 2 diabetes not treated with insulin or sulphonylureas where there is an agreed purpose or goal to testing
- SMBG should be used only within a care package, accompanied by structured education which should include clear instructions as to the place of monitoring and how results can be used to reinforce lifestyle change, adjust therapy or alert healthcare professionals. This should include regular reviews to identify and support those who find it useful while discouraging those who gain no clinical benefit from continuing to test
- Individuals with non-insulin treated diabetes who are motivated by SMBG activity and use the information to maximise the effect of lifestyle and medication should be encouraged to continue to monitor
- Staff training in the use of SMBG to support changes in lifestyle and self-adjustment of medications is required
- Savings from a reduction in SMBG in individuals with non-insulin treated diabetes should be used to provide both structured education and training for professionals.
- Future research should focus on how to identify those who will gain most from SMBG and establish how they integrate it successfully into their approach to self-management.
Design: 12-month, prospective, cluster-randomised, multicentre study
Patients: 483 poorly controlled (HbA1c ≥7.5%), insulin-naïve type 2 diabetic patients from 34 primary care practices in the US
Intervention and comparison: Practices were randomised to an active control group with enhanced usual care or a structured testing group with enhanced usual care and at least quarterly use of structured SMBG. In the structured testing group, patients and physicians were trained to use a paper tool to collect/interpret 7-point glucose profiles over 3 consecutive days. The primary end point was HbA1c level measured at 12 months.
Outcomes and results: The 12-month intent-to-treat analysis (enhanced usual care, 13 practices, n=227; structured SMBG, 21 practices, n=256) showed significantly greater reductions in mean (SE) HbA1c in the structured SMBG compared with the enhanced usual care group: −1.2% (0.09) vs. −0.9% (0.10); P=0.04. Per protocol analysis showed even greater mean (SE) A1C reductions in the structured SMBG group compared with the enhanced usual care group: −1.3% (0.11) vs. −0.8% (0.11); P<0.003. Significantly more structured SMBG patients received a treatment change recommendation at the month 1 visit compared with enhanced usual care patients, regardless of the patient’s initial baseline HbA1c level: 179 (75.5%) vs. 61 (28.0%); P<0.0001. Patients in both groups displayed significant (P<0.0001) improvements in general well-being.
Sponsorship: Roche diagnostics
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