Index

Diagnosis Guidelines

Diabetes mellitus diagnostic rules:

Typical symptoms + 1 abnormal test
Asymptomatic + 2 abnormal tests (ideally repeat same test on a different day)

The biochemical cut-offs for diagnosing diabetes mellitus are the same regardless of type:

Test	Diabetes Cut-off	Pre-Diabetes
Fasting plasma glucose	≥7.0 mmol/L	6.1-6.9 mmol/L (impaired fasting glucose)
Random plasma glucose	≥11.1 mmol/L	n/a
2-hour post-oral glucose tolerance test	≥11.1 mmol/L	7.8-11.0 mmol/L (impaired glucose tolerance)
HbA1c	≥48 mmol/mol (6.5%)	42-47 mmol/mol (6.0-6.4%)

A 'finger prick' capillary blood glucose level CANNOT be used to diagnose diabetes mellitus.

HbA1c should not be used to diagnose diabetes mellitus in the following patient populations:

<18 y/o (as T1DM is common)
Pregnant women / within 2 months post-partum
Symptoms of diabetes for <2 months
People at high diabetes risk who are acutely ill.
Taking medication that may cause hyperglycaemia (e.g. long-term steroids)
Acute pancreatic damage, including pancreatic surgery.
End-stage renal disease

Causes of false HbA1c levels:

Falsely low HbA1c	Falsely high HbA1c
(↓ RBC lifespan → less time for glycation)	(↑ RBC lifespan → more time for glycation)
Acute blood loss Haemolytic anaemia Haemoglobinopathies Pregnancy Haemodialysis	Iron deficiency Vitamin B12 / folate deficiency

Management Guidelines

In acute symptomatic hyperglycaemia, consider sulfonylurea or insulin to quickly lower blood sugar.

Dietary advice:

Eat high-fibre, low-glycaemic-index sources of carbohydrate (e.g. fruit, vegetables, wholegrains and pulses)
Choose low-fat dairy products
Eat oily fish
Control intake of saturated and trans-fatty acids

Lifestyle advice:

Lose weight (if overweight)
Advice on physical activity
Smoking cessation
Limit alcohol intake

T2DM should be monitored via HbA1c levels

Every 3-6 months initially, and
Every 6 months once HbA1c level is stable

HbA1c targets:

If the patient is on lifestyle only or 1 drug that does not cause hypoglycaemia: HbA1c 48 mmol/mol (6.5%)
If the patient is on sulfonylurea: HbA1c 53 mmol/mol (7.0%)
If the patient is on 2 or more drugs: HbA1c 53 mmol/mol (7.0%)

Do not routinely offer self-monitoring in T2DM (unlike in T1DM).

Only offer self-monitoring if any of the following:

Patient is on insulin
Evidence of hypoglycaemic episodes
Patient is planning pregnancy / is pregnant
Patient is on oral medication that may increase their risk of hypoglycaemia while driving or operating machinery

Only offer intermittently scanned continuous glucose monitoring to:

Patients on multiple daily insulin injections, and
At least 1 of the following
- Recurrent / severe hypoglycaemia
- Impaired hypoglycaemia awareness
- Inability to self-monitor blood glucose by finger prick

Note that a lot of students overthink and overcomplicate this section, focusing too much on when exactly to step up and when exactly to add which drug.

In exams, questions tend to provide clean-cut HbA1c (i.e. within range or above range). Students are largely expected to know:

Intensify drug treatment if target not met (if within target, not necessary)
Choice of step 1 drug treatment
Choice of further steps of drug treatment relies mainly on the SGLT-2 inhibitor criteria and the side effect / safety profile of other drugs

If the patient has chronic heart failure / atherosclerotic CVD / QRISK ≥10%

Offer metformin + SGLT-2 inhibitor
Don't start both at the same time: first start metformin, and once tolerability is confirmed, start SGLT-2 inhibitor

All other patients: metformin monotherapy

Always start with standard-release metformin
If the patient cannot tolerate, then attempt modified-release metformin
Only if the patient cannot tolerate modified-release metformin, consider an alternative drug

If the patient meets the criteria for SGLT-2 inhibitor → offer SGLT-2 inhibitor monotherapy
Otherwise → offer DPP-4 inhibitor / pioglitazone / sulfonylurea

NICE recommends if HbA1c >58 mmol/mol (7.5%) despite monotherapy → intensify treatment

Offer dual therapy (add one of the following to current monotherapy):

DPP-4 inhibitor
Pioglitazone
Sulfonylurea
SGLT-2 inhibitor (only if there is chronic heart failure / atherosclerotic CVD / QRISK >10%)

At any stage, if the patient meets the criteria for SGLT-2 inhibitor (develops chronic heart failure / atherosclerotic CVD / QRISK >10%), consider adding or replacing an existing drug with an SGLT-2 inhibitor

If dual therapy is not controlling HbA1c under the agreed target → consider either the following:

Triple therapy by adding DPP-4 inhibitor / pioglitazone / sulfonylurea / SGLT-2 inhibitor (only if there is chronic heart failure / atherosclerotic CVD / QRISK >10%)

Insulin (+ metformin) (other oral agents usually stopped to minimise hypoglycaemia risk)
- 1st line: human isophane insulin (NPH insulin) (once or twice daily basal insulin)
- 2nd line (1st line option not achieving control): basal bolus insulin regimen or use biphasic insulin twice daily
- If patient needs assistance to inject insulin: use long-acting insulin (detemir / glargine)

If triple therapy (including metformin) is not effective → consider switching 1 drug for a GLP-1 mimetic (e.g. liraglutide, semaglutide) if

BMI ≥35 kg/m² + obesity associated medical or psychological problems, or
Insulin is not appropriate, or
Weight loss would benefit other significant obesity-related comorbidities

At any stage, if the patient meets the criteria for SGLT-2 inhibitor (develops chronic heart failure / atherosclerotic CVD / QRISK >10%), consider adding or replacing an existing drug with an SGLT-2 inhibitor

T2DM and CKD Guidelines

ALL T2DM patients should be tested for CKD with:

eGFR (creatinine), and
Urine ACRAlbumin:creatinine ratio (≥3 mg/mmol is defined as clinically important proteinuria)

Offer ACE inhibitor / ARB if ACRAlbumin:creatinine ratio >3 mg/mmol (those with T2DM and CKD)

Add SGLT-2 inhibitor (in addition to ACE inhibitor / ARB) if ACR >3 mg/mmol

Exact recommendation: offer if >30 mg/mmol and consider if >3 mg/mmol

See this article for more information on CKD management.

References

NICE guideline Type 2 diabetes in adults: management
NICE CKS Diabetes - type 2

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Type 2 Diabetes (T2DM)

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Self Blood Glucose Monitoring

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