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Glycaemic targets should be individualised for each patient and reviewed at least annually
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HbA1c is the most practical target tool as reflects glycaemic control over the previous 3 months
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Should be measured 3 monthly until to target and then 6 monthly if stable control
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The target HbA1c in most patients with diabetes is < 53 mmol/mol
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A lower target HbA1c < 48 mmol/mol is appropriate when the risk of hypoglycaemia is low (i.e. not on insulin and/or sulfonylureas) and in patients who are either:
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Young
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Considering pregnancy or pregnant
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Have diabetic microvascular complications (particularly retinopathy and nephropathy)
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A higher HbA1c target (e.g. 54 – 70 mmol/mol) may be more appropriate when the risks of hypoglycaemia likely outweigh the benefits of tight glycaemic control such as:
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Life expectancy is limited by non-diabetes related comorbidities
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Previous episodes of severe hypoglycaemia
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Significant hypoglycaemic unawareness
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Frail elderly and/or with cognitive impairment
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Functionally dependent
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NB: Hypoglycaemia usually only occurs in patients treated with insulin and/or sulfonylureas
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Self-monitoring of blood glucose levels (SMBG) are recommended when:
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Considering starting or already on sulfonylurea or insulin therapy
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Concerns over hypoglycaemia on any therapy
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Planning pregnancy and during pregnancy
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Measurement of HbA1c is unreliable
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An HbA1c may be unreliable in:
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Any haemoglobinopathy e.g. sickle cell anaemia, thalassemia
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Altered red cell turnover e.g. bleeding, haemolysis, significant iron deficiency etc.
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Post blood transfusion
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Second and third trimesters of pregnancy
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Self-monitoring of glucose levels is an important aspect of diabetes management and can be done via capillary blood glucose (CBG) or continuous glucose monitoring (CGM)
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Every patient with diabetes should ideally be provided with a CareSens N or N POP glucometer and CareSens N glucose test strips to check CBG levels (the CareSens N voice glucometer may be useful if visual impairment) - NB: only those on sulfonylureas and/or insulin or who are pregnant qualify for funded monitoring
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Both real-time CGM (rtCGM, e.g. Dexcom and Guardian systems) and intermittently scanned CGM (isCGM, e.g. Freestyle Libre system) can be very beneficial when the necessary information cannot be obtained from CBG monitoring for whatever reason. Unfortunately all CGM systems in Aotearoa New Zealand are not funded and are expensive (rtCGM is likely more effective but more expensive than isCGM), but many practices now have access to some funded CGM sensors. NB: Consider using CGM when lack of CBG monitoring is affecting patient safety and/or timely treatment decisions
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The frequency of monitoring glucose levels should be individualised according to what information is required for medication changes and patient safety, and ideally should include:
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Whenever symptomatic of hypoglycaemia or hyperglycaemia
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Fasting glucose levels when on nocte basal insulin
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To check for 3 days before a dose change
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To check for 3 days before a dose change
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Periodic checking of glucose levels at other times of the day
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Checking levels before meals and bed on 1-2 days per week is often preferable to sporadic checks at different times on different days
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Pre and 1 or 2 hour post glucose levels at all meals during pregnancy
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At least 3-4 times per day when unwell as part of sick day management
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More frequent monitoring may be required to ensure safety from hypoglycaemia and the necessary information for dose changes, particularly around driving and in those that do shift work
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Patients may also choose to monitor more frequently to improve their glycaemic control.
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Glucose targets in most non-pregnant adults with diabetes are:
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Fasting glucose levels < 7 mmol/L
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2-3 hour post-meal glucose levels < 10 mmol/L
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Time in target range (3.9 - 10 mmol/L) > 70% on CGM
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No hypoglycaemia (< 4 mmol/L) in patients treated with sulfonylureas and/or insulin
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Asymptomatic mild hypoglycaemia in patients not on insulin or sulfonylureas is common and is not concerning
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Please see Diabetes in Pregnancy for glucose targets during pregnancy
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Monitoring of capillary ketone levels is only recommended in patients who are unwell and have:
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Type 1 diabetes
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Diabetes due to loss of pancreatic function
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Type 2 diabetes on anSGLT2 inhibitorand/or previous diabetic ketoacidosis (DKA) when unwell (currently only in practice and/or hospital setting)
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NB: These patients require a CareSens Dual glucometer with CareSens Pro glucose test strips and KetoSens ketone test strips. At present, patients with type 2 diabetes on a SGLT2 inhibitor do not qualify for a funded CareSens Dual glucometer