Target HbA1c levels

Involve adults with type 2 diabetes in decisions about their individual HbA1c target. Agree an individualised HbA1c target based on the person's needs and circumstances. Encourage them to achieve the target and maintain it unless any resulting adverse effects (including hypoglycaemia), or their efforts to achieve their target, impair their quality of life. The benefits of tight blood glucose control are not immediate, but accrue over years to decades. It is important to explain this to patients. NICE have produced a patient decision aid which is designed to help individual patients participate in decision making about target HbA1c levels. It summarises information on the things people most often want to think about when they are deciding on what new target HbA1c level is best for them.

The NICE guideline states that a target HbA1c level of 48 mmol/mol is recommended for adult patients with type 2 diabetes managed either by lifestyle and diet, or by lifestyle and diet combined with a single drug not associated with hypoglycaemia. For adults on a drug associated with hypoglycaemia, aim for an HbA1c level of 53 mmol/mol.

If HbA1c levels are not adequately controlled by a single drug and rise to 58 mmol/mol or higher:

• reinforce advice about diet, lifestyle and adherence to drug treatment and
• support the person to aim for an HbA1c level of 53 mmol/mol and
• intensify drug treatment (see drug treatment guidance below)

Consider relaxing the target HbA1c level on an individual basis, with particular consideration for people who are older or frail that may be unlikely to achieve longer‑term risk‑reduction benefits and perhaps have a reduced life expectancy, or if tight blood glucose control poses a high risk of the consequences of hypoglycaemia, for example patients with increased fall risk, and patients who drive or operate machinery as part of their job. Due consideration should also be given to people who have impaired awareness of hypoglycaemia, and those with significant comorbidities.

Patients diagnosed at a young age (e.g. under 55) should aim for strict NICE targets, unless there are strong reasons not to (such as hypoglycaemic episodes or occupation). Patients with microvascular complications (especially albuminuria or retinopathy) should also normally aim for strict NICE targets. For patients with life expectancy less than 5-10 years or who are vulnerable to hypoglycaemia, it would be reasonable to raise the HbA1c targets by around 10 mmol/mol. Patients with less than 1-2 years life expectancy should be treated primarily for symptom control.

If adults with type 2 diabetes achieve an HbA1c level that is lower than their target and they are not experiencing hypoglycaemia, encourage them to maintain it. Be aware that there are other possible reasons for a low HbA1c level, for example, deteriorating renal function or sudden weight loss.

Frequency of monitoring HbA1c

In adults with type 2 diabetes, measure HbA1c levels at:

• 3–6-monthly intervals (tailored to individual needs), until the HbA1c is stable on unchanging therapy
• 6-monthly intervals once the HbA1c level and blood glucose lowering therapy are stable.

Do not routinely offer self-monitoring of blood glucose levels for adults with type 2 diabetes unless the person is on insulin, on oral medication that may increase their risk of hypoglycaemia, is pregnant or planning to become pregnant, or if there is evidence of hypoglycaemic episodes.

Consider short-term self-monitoring of blood glucose levels in adults with type 2 diabetes (and review treatment as necessary), when starting treatment with oral or intravenous corticosteroids or to confirm suspected hypoglycaemia.

Adopt an individualised approach, take into account the patient’s:

• personal preferences
• comorbidities
• risks from polypharmacy
• their ability to benefit from long-term interventions because of reduced life expectancy

Clinicians may offer a 3-6 month trial of lifestyle and diet interventions before commencing drug treatment, although for some patients it may be appropriate to begin treatment with metformin at diagnosis.

Assessment of patient’s cardiovascular and renal status at baseline

NICE guidance [NG28] recommendations on drug treatment are based on the patient’s cardiovascular history or risk of developing cardiovascular disease, renal function (chronic kidney disease) and HbA1c.

Established atherosclerotic cardiovascular disease (NG28 definition)
This includes coronary heart disease, acute coronary syndrome, previous myocardial infarction, stable angina, previous coronary or other revascularisation, cerebrovascular disease (ischaemic stroke and transient ischaemic attack) and peripheral arterial disease.

High risk of developing cardiovascular disease (NG28 definition)
Adults with type 2 diabetes who have:

• QRISK2 more than 10% in adults aged 40 and over, or
• an elevated lifetime risk of cardiovascular disease (defined as the presence of 1 or more cardiovascular risk factors in someone under 40: hypertension, dyslipidaemia, smoking, obesity, and family history (in a first-degree relative) of premature cardiovascular disease)

Optimum cardiovascular risk factor reduction
This should be undertaken alongside intensification of blood glucose lowering therapies. Control of BP, lipids and other lifestyle factors (e.g. smoking cessation) will have a larger impact on risk reduction than tight blood glucose control.

Choice of drug treatment

For adults with type 2 diabetes, discuss the benefits and risks of drug treatment, and the options available.
Base the choice of drug treatment(s) on:

• the effectiveness of the drug treatment(s) in terms of metabolic response and cardiovascular and renal protection
• safety and tolerability of the drug treatment(s)
• the person's individual clinical circumstances, for example, comorbidities, contraindications, weight and risks from polypharmacy
• the person's individual preferences and needs
• the licensed indications or combinations available
• monitoring requirements
• cost (if 2 drugs in the same class are appropriate, choose the option with the lowest acquisition cost)

Reviewing and changing treatments

At each point, think about and discuss the following with the person: 

• how to optimise their current treatment regimen before thinking about changing treatments, taking into account factors such as:
  • adverse effects
  • adherence to existing medicines – reinforce at each review
    
  • the need to revisit advice about diet and lifestyle – if the patient’s attention to these have lapsed since the last review, the HbA1c may show no change even if the medication is working
    
  • prescribed doses and formulations
    
• stopping medicines that are not tolerated
  
• stopping medicines that have had no impact on glycaemic control or weight, unless there is an additional clinical benefit, such as cardiovascular or renal protection, from continued treatment
• whether switching rather than adding drugs could be effective
  

Intensification of therapy: 

• Consider on average 3 months after making a change to medication and guided by repeat HbA1c.
• Be flexible according to clinical circumstances e.g. consider earlier intensification in more acute symptomatic hyperglycaemia; intensification can be guided by blood glucose monitoring results rather than HbA1c.
• In patients with poorly controlled diabetes, if HbA1c remains high at 3 months, it is unlikely that significant further improvement will be seen at 6 months.

Rescue therapy at any phase of treatment

If an adult with type 2 diabetes is symptomatically hyperglycaemic, consider insulin or a sulfonylurea, and review treatment when blood glucose control has been achieved.

Click here for NICE NG28 visual summary

If HbA1c rises above 48mmol/mol after 3-6 months of diet and lifestyle intervention, commence treatment.

Assess the patient for the following conditions before starting treatment.

• Chronic heart failure (CHF)
• Established atherosclerotic cardiovascular disease (ACVD): for NG28 definition, see Pharmacological treatment above
• High risk of cardiovascular disease: for NG28 definition, see Pharmacological treatment above

Initial treatment (HbA1c exceeds 48mmol/mol)

Start treatment with metformin standard-release (see Antidiabetic drugs for dose titration). If not tolerated, switch to metformin modified-release.

When metformin tolerability is established, dual therapy may be commenced:

• Add a SGLT2 inhibitor for patients with established ACVD or CHF
• Consider adding a SGLT2 inhibitor for patients with no established CVD but high cardiovascular risk

If metformin is not appropriate or not tolerated and the patient has:

• Cardiovascular disease or CHF, start SGLT2 inhibitor monotherapy
• A high cardiovascular risk, consider starting SGLT2 inhibitor monotherapy
• If none of the above conditions are present: start monotherapy with either a sulfonylurea or pioglitazone, or (either a DPP-4 inhibitor or a SGLT2 inhibitor) (preferred order for treatment selection)

At any time during treatment

If new cardiovascular disease or CHF, a SGLT2 inhibitor is recommended, either:

• Add a SGLT2 inhibitor if HbA1c is above target,
  • maximum of triple oral therapy (if receiving metformin) or dual oral therapy (if metformin contraindicated or not tolerated), OR
• Replace an existing oral agent with a SGLT2 inhibitor if there is no need for intensification and a risk of hypoglycaemia or side effects
• Review the patient’s treatment regimen to ensure it is appropriate for their current clinical circumstances

Consider a SGLT2 inhibitor if no established disease but risk of cardiovascular disease has increased.

Dapagliflozin or empagliflozin are also recommended as an add-on to an ACE inhibitor or ARB for CKD in patients with type 2 diabetes. For criteria for initiation of ACE inhibitors or ARBs and dapagliflozin or empagliflozin for CKD, refer to the dapagliflozin and empagliflozin entries. 

If HbA1c exceeds 58mmol/mol or individually agreed threshold

• Add or switch drugs up to a maximum of triple oral therapy (if receiving metformin) or dual oral therapy (if metformin contraindicated or not tolerated):
  • Sulfonylurea, or
  • Pioglitazone (contraindicated in heart failure), or
  • DPP-4 inhibitor (avoid alogliptin and saxagliptin [non-formulary] in heart failure), or
  • SGLT2 inhibitor
• If triple oral therapy (with metformin) is not sufficiently effective, not tolerated or contraindicated, see criteria for GLP-1 mimetic and tirzepatide below.

OR

Insulin-based treatment (go to ‘Commencing insulin in type 2 diabetes’ below)

GLP-1 mimetics and tirzepatide: If triple oral therapy (with metformin) is not sufficiently effective, not tolerated or contraindicated

GLP-1 mimetic shortage (National Patient Safety Alert 3rd January 2024): For more information, refer to Antidiabetic drugs.

Continue metformin and replace one of the other oral drugs with a GLP 1 mimetic* or tirzepatide for patients who:

• have a body mass index (BMI) of 35 kg/m² or higher (adjust accordingly for people from Black, Asian and other minority ethnic groups) and specific psychological or other medical problems associated with obesity or
• have a BMI lower than 35 kg/m² and:
  • for whom insulin therapy would have significant occupational implications, or
  • weight loss would benefit other significant obesity-related comorbidities.

Do not combine:

• a DPP-4 inhibitor and a GLP-1 mimetic, or
• either a DPP-4 inhibitor or a GLP-1 mimetic with tirzepatide

*Continuation of a GLP-1 mimetic
Only continue GLP-1 mimetic therapy if the adult with type 2 diabetes has had:

• a beneficial metabolic response (a reduction of at least 11 mmol/mol [1.0%] in HbA1c, and
• weight loss of at least 3% of initial body weight in 6 months)

When starting insulin, use a structured programme and continue to offer metformin for people without contraindications or intolerance. Review the continued need for other blood glucose lowering therapies.

Canagliflozin, dapagliflozin or empagliflozin in combination with insulin with or without other antidiabetic drugs may be recommended as an option for treating type 2 diabetes.

Only offer insulin and a GLP-1 mimetic with specialist care advice and ongoing support from a consultant-led multidisciplinary team.

Start insulin therapy for adults with type 2 diabetes from a choice of a number of insulin types and regimens:

• Offer isophane insulin (NPH) once or twice daily according to need.
• Consider starting both isophane (NPH) and short-acting insulin (particularly if the person's HbA1c is 75 mmol/mol or higher), administered either:
  • separately or
  • as a pre-mixed (biphasic) human insulin preparation.
• Consider as an alternative to isophane insulin (NPH), using insulin detemir or glargine if:
  • the person needs assistance to inject insulin,
  • the person's lifestyle is restricted by recurrent symptomatic hypoglycaemic episodes or
  • the person would otherwise need twice-daily isophane insulin (NPH) in combination with oral blood glucose lowering drugs.
• Consider pre-mixed (biphasic) preparations that include short-acting insulin analogues, rather than pre-mixed (biphasic) preparations that include short-acting human insulin preparations, if:
  • the person prefers injecting insulin immediately before a meal
  • hypoglycaemia is a problem or
  • blood glucose levels rise markedly after meals.

Consider switching to insulin detemir or insulin glargine from isophane insulin (NPH) in adults with type 2 diabetes:

• who do not reach their target HbA1c because of significant hypoglycaemia or
• who experience significant hypoglycaemia on isophane insulin (NPH) irrespective of the level of HbA1c reached or
• who cannot use the device needed to inject isophane insulin (NPH) but who could administer their own insulin safely and accurately if a switch to one of the long-acting insulin analogues was made or
• who need help from a carer or healthcare professional to administer insulin injections and for whom switching to one of the long-acting insulin analogues would reduce the number of daily injections.

Monitor adults with type 2 diabetes for the need to change the regimen.

Monitor adults with type 2 diabetes who are on a basal insulin regimen (Isophane insulin [NPH], insulin detemir or insulin glargine) for the need for short-acting insulin before meals (or a pre-mixed [biphasic] insulin preparation).

Monitor adults with type 2 diabetes who are on pre-mixed (biphasic) insulin for the need for a further injection of short-acting insulin before meals or for a change to a basal bolus regimen with isophane insulin (NPH) or insulin detemir or insulin glargine, if blood glucose control remains inadequate.

NICE have produced a patient decision aid aimed at helping adults with type 2 diabetes think about their options for controlling their blood glucose to try to reduce the long-term risks of diabetes. The decision aid is intended to help adults with type 2 diabetes at the first intensification of drug treatment. It is not intended for use at other stages in the care pathway, or for women with type 2 diabetes who are pregnant or planning to become pregnant. It summarises information on the things people most often want to think about and discuss with their healthcare team when they are deciding on what new target HbA1c level is best for them, and which medicines they might try to achieve this target.

Primary prevention

Do not offer antiplatelet therapy (aspirin or clopidogrel) for adults with type 2 diabetes without CVD

Secondary prevention

All patients with diabetes and a history of CVD should receive antiplatelet therapy (see section 2.9 Antiplatelet drugs).

Patients with Type 2 diabetes should have their lipids managed in line with the advice in Chapter 2 of the formulary.

Patients with Type 2 diabetes should have hypertension managed in line with the advice provided in Chapter 2 of the formulary.