Blood glucose monitoring

SMBG by patients should be an integral part of diabetes self-management since the information obtained may be used to guide therapy and assess the efficacy of treatment. SMBG also serves as a useful educational tool to improve patient compliance and participation in diabetes self-management.

Indication for SMBG

B

Self-monitoring of blood glucose is recommended for patients with type 1 or type 2 diabetes who are using insulin.

Grade B, Level 2⁺⁺

SMBG is a fundamental component of self-management in patients with insulin-treated diabetes.^138-139 SMBG can guide adjustment of insulin and allows patients to assess whether glycaemic targets are being achieved.¹⁴⁰ Results of SMBG can also be useful in preventing hypoglycaemia in this group of patients.

D

Self-monitoring of blood glucose should be considered in the following groups of patients with type 2 diabetes who are not treated with insulin:

• those at increased risk of developing hypoglycaemia or its consequences (e.g., patients who are using sulphonylureas)

• those pregnant patients with pre-existing diabetes or gestational diabetes

• those experiencing acute illness

• those who have failed to achieve glycaemic goals

• those undergoing fasting, for example, during Ramadan

Grade D, Level 4

The evidence for the benefit of routine SMBG in non-insulin treated patients with type 2 diabetes is conflicting. A meta-analysis of SMBG in non-insulin treated patients with type 2 diabetes concluded that some regimen of SMBG was associated with a reduction in HbA_1c of 0.4%.¹⁴¹ However, several recent trials of higher qualities have questioned the clinical and cost-effectiveness of SMBG for non-insulin treated patients with type 2 diabetes. One large randomised controlled trial done in the UK (DIGEM) found no significant effect of SMBG on HbA_1c between groups randomised to standard care (no self-monitoring), less intensive SMBG with nurse-practitioner interpretation of results and more intensive SMBG with self interpretation of results. The study also reported a negative impact of SMBG on quality of life and economic analysis indicated it was not cost effective if used routinely.^142-143 A more recent study (ESMON) recruited newly diagnosed patients with type 2 diabetes and a uniform treatment algorithm based on HbA_1c targets was applied to both SMBG and non-SMBG groups. At 12 months, HbA_1c was reduced in both groups and no significant difference between the groups was observed.¹⁴⁴

Frequency of self-monitoring of blood glucose

B

Self-monitoring of blood glucose should be carried out 3 or more times daily for patients with type 1 diabetes.

Grade B, Level 2⁺⁺

For patients with type 1 diabetes, a retrospective cohort study showed that mean HbA_1c was significantly decreased in patients who carried out SMBG at least 3 times a day compared to those who performed an average of 1 SMBG a day.¹³⁸

For insulin-treated type 2 diabetic patients, testing 2 or 3 times a day on 2 to 3 days a week would be appropriate. The optimal frequency and timing of SMBG for non-insulin treated patients with type 2 diabetes is unclear, but it should be frequent enough to facilitate reaching glucose targets.

GPP

For patients with unstable metabolic control, changes in daily routine, alterations of treatment regimens or acute illness, the frequency of self-monitoring of blood glucose should be increased.

GPP

Methodology and accuracy

GPP

Healthcare professionals should be familiar with the practical use of glucometers.

GPP

Glucometer

With improved technology, most brands of glucometers on the market today are reliable and robust. However, the accuracy of glucometers is highly operator-dependent. It is important for health care professionals to evaluate each patient’s monitoring technique, both initially and at regular intervals. Common errors are: inadequate amount of blood sample, using defective or expired test strips, incorrect calibration, forgetting to calibrate, and instrument failure. Most glucometers are designed to test capillary whole blood (i.e. blood from the finger).

Slightly higher results may be observed when using venous samples, due to differences in the way the electrodes react to venous and capillary

blood glucose values. Users should know whether their glucometer and strips provide whole blood or plasma results. In general, caution should also be exercised in interpreting values in the hypoglycaemia (<2.0 mmol/l) and severe hyperglycaemia (>20.0 mmol/l) ranges.

Initial training for the use of blood glucometers should be provided by qualified staff i.e. nurses, doctors or pharmacists rather than asking the patient to follow the manufacturer’s manual.

B

To ensure optimal benefit from self-monitoring of blood glucose, patients must be educated on the interpretation of glucose levels.¹⁴⁵

Grade B, Level 1⁺

GPP

Periodic reviews are recommended to verify users’ competency, together with comparisons between results from patient self-testing of blood glucose in the clinic and simultaneous laboratory testing.

GPP

GPP

It is recommended that calibration checks of meters are periodically conducted using standard solutions according to the manufacturer’s recommendations.

GPP

Continuous glucose monitoring (CGM)

Although self-monitoring of blood glucose is an integral part of the diabetes self-management in patients with type 1 diabetes, many patients do not routinely monitor glucose levels either post-prandially or overnight, which may leave undetected episodes of hyperglycaemia and hypoglycaemia respectively.¹⁴⁶ Systems that allow continuous monitoring of glucose by means of subcutaneous sensors which measure interstitial glucose levels are now available. These sensors require calibration with SMBG, and the latter are still recommended

older using intensive insulin therapy and CGM experienced significant reduction in HbA_1c of 0.5% compared to usual intensive insulin therapy with SMBG.¹⁴⁷

D

Continuous glucose monitoring may be used as a supplemental tool to SMBG in patients with hypoglycaemia unawareness and/or frequent hypoglycaemic episodes.

Grade D, Level 3

Im Dokument Diabetes Mellitus (Seite 82-86)