Evidence

Evidence tables

This table is a summary of the analysis reported in a guideline (underpinned by a systematic review) that focuses on the above important clinical question.


Confidence in the evidence is very low or low where GRADE has been performed and there is a trade off between benefits and harms of the intervention.


Population: Adults with type 2 diabetes

Intervention: Self-monitoring blood glucose

Comparison: No self-monitoring blood glucose (including usual care and self-monitoring of urine glucose)

OutcomeEffectiveness (BMJ rating)?Confidence in evidence (GRADE)?

Haemoglobin A1c (HbA1c) (follow up: 24-52 weeks)

Favours intervention

Low

Fasting blood glucose (mmol/L) (follow up: 26-52 weeks)

Favours intervention

Low

Post-prandial blood glucose (mg/dL) at 26 weeks for adults with type 2 diabetes on diet, anti-diabetic, and/or insulin medicines (follow up: 6 months)

Favours intervention

Low

Any hypoglycaemia from 26-52 weeks (follow up: 6-12 months)

Favours comparison

Low

Severe hypoglycaemia from 26-52 weeks (follow up: 6-12 months)

No statistically significant difference

Low

Adverse events at 6 months for adults with type 2 diabetes on oral anti-diabetes medicines (follow up: 6 months) 

No statistically significant difference

Moderate

Recommendations as stated in the source guideline

The guideline development group states: do not routinely offer self-monitoring of blood glucose levels for adults with type 2 diabetes unless:

  • the person is on insulin or

  • there is evidence of hypoglycaemic episodes or

  • the person is on oral medication that may increase their risk of hypoglycaemia while driving or operating machinery or

  • the person is pregnant, or is planning to become pregnant.

Note

The guideline development group noted that self-monitoring of blood glucose provides the potential for tight glycaemic control which reduces the risk of diabetes-related complications. However, the impact on hypoglycaemic events is important in determining the safety and acceptability in patients.

This evidence table is related to the following section/s:

This table is a summary of the analysis reported in a guideline (underpinned by a systematic review) that focuses on the above important clinical question.


Confidence in the evidence is very low or low where GRADE has been performed and the intervention may be more effective/beneficial than the comparison for key outcomes. However, this is uncertain and new evidence could change this in the future.


Population: Pregnant women with gestational diabetes ᵃ

Intervention: Tighter glucose control

Comparison: Less tight glucose control

OutcomeEffectiveness (BMJ rating)?Confidence in evidence (GRADE)?

Fasting blood glucose < 5.3 mmol/L versus ≥5.3 mmol/L in women with gestational diabetes

Pre-eclampsia

Favours intervention

Very Low

Large for gestational age

Favours intervention

Very Low

Strict control of 1.5 hour postprandial blood glucose (< 6.7 mmol/L) versus customary control (<7.8 mmol/L) in women with pre-existing type 1 diabetes ᵃ

Mean HbA1c (by trimester) ᵇ

No statistically significant difference

Very Low

1 to 2 hour postprandial blood glucose of ≤7.8 mmol/L versus >7.8 mmol/L in women with pre-existing diabetes ᵃ

Macrosomia at 29 to 32 weeks’ gestation

Favours intervention

Very Low

2 hour postprandial blood glucose <6.4 mmol/L versus ≥6.4 mmol/L in women with gestational diabetes

Pre-eclampsia

Favours intervention

Very Low

Large for gestational age

Favours intervention

Very Low

Recommendations as stated in the source guideline

The National Institute of Health and Care Excellence (NICE) 2015 guideline on Diabetes in Pregnancy makes the following recommendation:

Advise pregnant women with any form of diabetes to maintain their capillary plasma glucose below the following target levels, if these are achievable without causing problematic hypoglycaemia:

  • Fasting: 5.3 mmol/litre AND

  • 1 hour after meals: 7.8 mmol/litre OR

  • 2 hours after meals: 6.4 mmol/litre.

Note

The guideline committee noted that some of the included studies used very short gestational intervals and that blood glucose control may require adjusting for women depending on their personal circumstances and treatment.

ᵃ The guideline committee considered evidence for pregnant women with type 1 diabetes, type 2 diabetes, or gestational diabetes. They extrapolated the evidence to all women with diabetes during pregnancy, as ideally blood glucose levels during pregnancy should be as near to normal as is possible, without increasing the risk of hypoglycaemia due to the linear relationship between maternal blood glucose and the risk of complications, such as macrosomia. This table therefore reports the evidence in women with gestational diabetes and any relevant indirect evidence from pregnant women with pre-existing diabetes, which is included in the guideline recommendation, when no direct evidence was available.

ᵇ The guideline committee included data for the first, second, and third trimesters, all of which show no statistically significant difference between treatment groups, underpinned by very low-quality evidence

This evidence table is related to the following section/s:

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