Type 2 diabetes in adults
Evidence
This page contains a snapshot of featured content which highlights evidence addressing key clinical questions including areas of uncertainty. Please see the main topic reference list for details of all sources underpinning this topic.
BMJ Best Practice evidence tables
Evidence tables provide easily navigated layers of evidence in the context of specific clinical questions, using GRADE and a BMJ Best Practice Effectiveness rating. Follow the links at the bottom of the table, which go to the related evidence score in the main topic text, providing additional context for the clinical question. Find out more about our 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 high or moderate to high where GRADE has been performed and the intervention is more effective/beneficial than the comparison for key outcomes.
Population: Adults with CKD and type 2 diabetes who are taking an angiotensin-II receptor antagonist or an ACE inhibitor ᵃ
Intervention: Existing therapy plus an SGLT2 inhibitor (e.g., canagliflozin, dapagliflozin, ertugliflozin, empagliflozin)
Comparison: Existing therapy plus placebo
| Outcome | Effectiveness (BMJ rating)? | Confidence in evidence (GRADE)? |
|---|---|---|
Renal composite – end stage kidney disease, doubling serum creatinine, renal death | Favours intervention | Moderate ᵇ |
Cardiovascular composite: 3-point MACE | Favours intervention | Moderate ᵇ |
All cause mortality | Favours intervention | High |
Cardiovascular death | Favours intervention | High |
Non-fatal myocardial infarction | No statistically significant difference | Moderate |
Non-fatal stroke | No statistically significant difference | Moderate |
Fatal/non-fatal myocardial infarction | No statistically significant difference | Moderate |
Fatal/non-fatal stroke | Favours intervention | High |
Hospitalisation for heart failure | Favours intervention | High |
End stage kidney disease | Favours intervention | High |
Doubling of serum creatinine | Favours intervention | High |
Estimated glomerular filtration rate (eGFR) reduction >50% | Favours intervention | High |
Dialysis | Favours intervention | High |
eGFR at 6 months | Favours comparison | High |
eGFR last available data point >2 years | Favours intervention | Moderate |
Percentage change from baseline Urine Albumin Creatinine Ratio (UACR): at 6 months and at last available data point >2 years | No statistically significant difference | High |
Diabetic ketoacidosis | No statistically significant difference | Very Low |
Amputation | No statistically significant difference | Low |
Fracture | No statistically significant difference | Moderate |
Acute kidney injury | No statistically significant difference | Moderate |
Hypoglycaemia | No statistically significant difference | Low |
Genitourinary infection | Occurs more commonly with SGLT2 inhibitors compared with placebo (favours comparison) | Low |
Recommendations as stated in the source guideline For adults with type 2 diabetes and CKD who are taking an angiotensin-II receptor antagonist or an ACE inhibitor (titrated to the highest licensed dose that they can tolerate), offer an SGLT2 inhibitor (in addition to the angiotensin-II receptor antagonist or ACE inhibitor) if: ACR is over 30 mg/mmol and they meet the criteria in the marketing authorisation (including relevant estimated glomerular filtration rate [eGFR] thresholds). For adults with type 2 diabetes and CKD who are taking an angiotensin-II receptor antagonist or an ACE inhibitor (titrated to the highest licensed dose that they can tolerate), consider an SGLT2 inhibitor (in addition to the angiotensin-II receptor antagonist or ACE inhibitor) if: ACR is between 3 and 30 mg/mmol and they meet the criteria in the marketing authorisation (including relevant eGFR thresholds).
Note The guideline committee made a research recommendation for SGLT2 inhibitors for people of different ethnicities due to variation in the risk of macro/microvascular complications for a given level of eGFR. Where possible the guideline stratified outcomes by eGFR and ACR at baseline. The guideline committee noted substantial differences between studies in baseline ACR levels, but the majority of trials were in a population with A3 proteinuria (ACR >30 mg/mmol). Overall, they found that the quality of evidence, as rated by GRADE, was sufficient to support a strong recommendation to offer SGLT2 inhibitors to people with type 2 diabetes and A3 proteinuria, but only a weak recommendation for those with A2 proteinuria (ACR between 3 and 30 mg/mmol). ᵃ The guideline committee also searched for evidence in children and young people with CKD and type 2 diabetes mellitus but only found evidence in adults. ᵇ This outcome was downgraded only because of its composite nature, which the guideline panel felt made it less useful for decision making.
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
| Outcome | Effectiveness (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:
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)
| Outcome | Effectiveness (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:
Cochrane Clinical Answers
Cochrane Clinical Answers (CCAs) provide a readable, digestible, clinically focused entry point to rigorous research from Cochrane systematic reviews. They are designed to be actionable and to inform decision making at the point of care and have been added to relevant sections of the main Best Practice text.
- What are the effects of diet, physical activity, or both in people at increased risk of developing type 2 diabetes mellitus?
- In people with increased risk of developing type 2 diabetes mellitus, what are the preventative effects of alpha‐glucosidase inhibitors compared with exercise/diet or placebo or metformin?
- Can glucagon‐like peptide (GLP)‐1 analogs prevent or delay the development of type 2 diabetes?
- For people at risk for developing type 2 diabetes mellitus, how does metformin compare with diet and exercise?
- For adults with inadequately controlled type 2 diabetes (T2DM), how does metformin‐sulfonylurea compare with alternative metformin combinations?
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