MONITORING GLYCEMIC CONTROL

1. MONITORING GLYCEMIC CONTROL 2003 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada

2. GLYCATED HEMOGLOBIN • A1C (previously called hemoglobin A1c, HbA1c) reflects glycemia over the usual 120-day life span of erythrocytes (red blood cells). • Measurement of this indicator of treatment effectiveness should be undertaken approximately every 3 months to ensure that glycemic goals are being met or maintained. • A1C is the preferred standard for assessing glycated hemoglobin, and laboratories are encouraged to use assay methods for this test that are standardized against the DCCT reference.

3. SELF-MONITORING OFBLOOD GLUCOSE • Most people with diabetes benefit from self-monitoring of blood glucose levels. Patients should be taught to interpret monitoring results and make appropriate changes. • The frequency of self-testing should be determined individually. • In type 1 diabetes, 3 or more self-tests a day have been associated with a statistically and clinically significant 1% reduction in A1C levels. • In people with type 2 diabetes treated with medications, testing at least once daily was associated with a 0.6% lower A1C than less frequent monitoring.

4. SELF-MONITORING OFBLOOD GLUCOSE • Variability exists between glucose results obtained using self-monitoring devices and laboratory testing of plasma glucose. • A difference of < 20% between capillary and simultaneous fasting venous plasma glucose levels (when glucose level is > 4.2 mmol/L) is considered acceptable. • Meter results should be compared with laboratory measurement of plasma glucose at least annually, and when indicators of glycemic control do not match meter readings.

5. MONITORING -NEW TECHNOLOGIES • Meters are now available that allow self-monitoring using blood samples from sites other than the fingertip (usually the forearm). During periods of relatively stable blood glucose (before meals) the accuracy at alternate sites seems acceptable. During periods of rapid change in blood glucose levels (e.g. after meals or exercise), fingertip testing is more accurate. • Continuous monitoring of interstitial glucose concentrations may provide useful clinical information. Currently there are no analytical standards for this method and insufficient evidence to support its widespread use.

6. MONITORING -KETONE TESTING • Ketone testing is recommended for all people with type 1 diabetes during periods of acute illness, when preprandial BG levels are > 14.0 mmol/L and in the presence of symptoms of DKA. Ketone testing should be considered for people with type 2 diabetes prone to ketosis. • Testing methods that measure beta-hydroxybutyric acid (blood meter tests) may be preferred over those that measure acetoacetate or acetone (urine tests). Urine ketone testing is prone to false positive and false negative results in certain circumstances.

7. MONITORING GLYCEMIC CONTROL- RECOMMENDATIONS • A1C should be measured approximately every 3 months to ensure that glycemic goals are being met or maintained [Grade D, Consensus]. • All people with diabetes, who are able, should be taught how to self-manage their diabetes, including SMBG [Grade A, Level 1A].

8. MONITORING GLYCEMIC CONTROL- RECOMMENDATIONS • SMBG should be recommended as an essential part of daily diabetes management for all people using insulin or oral antihyperglycemic agents. People with type 1 diabetes should measure their BG at least 3 times per day. The frequency of SMBG in those with type 2 diabetes should be individualized depending on glycemic control and type of therapy. For most people with type 2 diabetes treated with insulin or oral antihyperglycemic agents, BG measurement at least once daily is recommended [Grade C, Level 3]. In many situations, more frequent testing may be required to provide the information needed to make behavioural or treatment adjustments required to achieve desired BG levels [Grade D, Consensus].

9. MONITORING GLYCEMIC CONTROL- RECOMMENDATIONS • SMBG should include both preprandial and 2-hour postprandial testing [Grade D, Consensus]. • Individuals who are conducting SMBG should receive initial instruction and periodic re-education regarding home glucose monitoring [Grade A, Level 1A]. • In order to ensure accuracy of BG meter readings, meter results should be compared with laboratory measurement of simultaneous venous FPG at least annually, and when indicators of glycemic control do not match meter readings [Grade D, Consensus].

10. MONITORING GLYCEMIC CONTROL- RECOMMENDATIONS • During periods of acute illness, people with type 1 diabetes should be instructed to perform ketone testing when preprandial BG levels are > 14.0 mmol/L and in the presence of symptoms of DKA [Grade D, Consensus]. If all of the conditions noted above are present in someone with type 2 diabetes, ketone testing should be considered [Grade D, Consensus].