The UK’s National Institute for Health and Care Excellence (NICE) has published newly updated guidelines for type 1 diabetes, which are presented in an abridged format in this article.
Type 1 diabetes is a chronic autoimmune disease that arises following the destruction of insulin-producing beta cells in the pancreas. As a result, people with type 1 diabetes require insulin therapy to adequately regulate blood glucose levels. In the short-term, people with type 1 diabetes may face significant challenges to daily living, such as hyperglycaemia, hypoglycaemia, and ketoacidosis, while long-term complications can occur in the form of both microvascular complications, such as diabetic retinopathy and neuropathy, and macrovascular complications, such as stroke and coronary artery disease.
The additional strain placed on healthcare resources when diabetes patients are hospitalised illustrates that diabetes-related complications impose not only a significant burden on patients and the healthcare system, but can also have a substantial societal impact due to productivity losses (such as days off work because of illness).
This year the UK’s National Institute for Health and Care Excellence (NICE) has updated a number of its diabetes-related clinical guidelines, including its one on type 1 diabetes care for adults (Type 1 diabetes in adults: Diagnosis and management (NG17)).
This guideline covers care and treatment for adults (aged 18 and over) with type 1 diabetes and includes advice on diagnosis, education and support, blood glucose management, cardiovascular risk, and identifying and managing long-term complications.
In August 2022, NICE amended its recommendations on blood pressure targets in people with diabetes to make them consistent with its recommendations on blood pressure control in its guidelines on chronic kidney disease and hypertension.
1.1 Diagnosis and early care plan
1.1.1 Make an initial diagnosis of type 1 diabetes on clinical grounds in adults presenting with hyperglycaemia. Bear in mind that people with type 1 diabetes typically (but not always) have one or more of:
▶ Rapid weight loss;
▶ Age of onset under 50 years;
▶ Body mass index (BMI) below 25kg/m2;
▶ Personal and/or family history of autoimmune disease. [2015, amended 2022]
1.1.2 Do not use age or BMI alone to exclude or diagnose type 1 diabetes in adults. 
1.1.3 Take into consideration the possibility of other diabetes subtypes and revisit the diagnosis at subsequent clinical reviews. Carry out further investigations if there is uncertainty (see recommendations 1.1.7 and 1.1.8). 
1.1.4 Measure diabetes-specific autoantibodies in adults with an initial diagnosis of type 1 diabetes, taking into account that:
▶ The false negative rate of diabetes-specific autoantibody tests is lowest at the time of diagnosis.
▶ The false negative rate can be reduced by carrying out quantitative tests for two different diabetes-specific autoantibodies (with at least one being positive). 
1.1.5 Do not routinely measure serum C peptide to confirm type 1 diabetes in adults. 
1.1.6 In people with a negative diabetes-specific autoantibody result, and if diabetes classification remains uncertain, consider measuring non-fasting serum C peptide (with a paired blood glucose). 
Revisiting initial diagnosis
1.1.7 At subsequent clinical reviews, consider using serum C peptide to revisit the diabetes classification if there is doubt that type 1 diabetes is the correct diagnosis. 
1.1.8 Take into account that the discriminative value of serum C peptide to diagnose type 1 diabetes increases the longer the test is done after initial diagnosis of diabetes. 
1.1.9 For people aged 60 and over presenting with weight loss and new-onset diabetes, follow recommendations on assessing for pancreatic cancer in the section on pancreatic cancer in the NICE guideline on suspected cancer: Recognition and referral. 
Early care plan
1.1.10 At diagnosis (or, if necessary, after managing critically decompensated metabolism), the diabetes professional team should work with adults with type 1 diabetes to develop a plan for their early care. This will generally require:
▶ Medical assessment to:
• Ensure the diagnosis is accurate (see recommendations 1.1.1 to 1.1.5);
• Ensure appropriate acute care is given when needed;
• Review medicines and detect potentially associated disease;
• Detect adverse vascular risk factors.
▶ Environmental assessment to understand:
• The social, home, work, and recreational circumstances of the person and their carers;
• Their lifestyle (including diet and physical activity);
• Other relevant factors, such as substance use.
▶ Cultural and educational assessment to:
• Find out what they know about diabetes;
• Help with tailoring advice, and with planning treatments, and diabetes education programmes.
▶ Assessment of their emotional wellbeing to decide how to pace diabetes education. 
1.1.11 Use the results of the initial diabetes assessment to agree a future care plan. This assessment should include:
▶ Acute medical history.
▶ Social, cultural, and educational history, and lifestyle review.
▶ Complications history and symptoms.
▶ Diabetes history (recent and long-term).
▶ Other medical history.
▶ Family history of diabetes and cardiovascular disease.
▶ Medication history.
▶ Vascular risk factors.
▶ General examination.
▶ Weight and BMI.
▶ Foot, eye, and vision examination.
▶ Urine albumin:creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR).
▶ Psychological wellbeing.
▶ Attitudes to medicine and self-care.
▶ Immediate family and social relationships, and availability of informal support. [2004, amended 2021]
1.1.12 Include the following in an individualised and culturally appropriate diabetes plan:
▶ When and where they will have their diabetes education, including their dietary advice (see the sections on education and information and dietary management).
▶ Initial treatment, including guidance on insulin injection and insulin regimens (see the sections on insulin therapy and insulin delivery).
▶ Self-monitoring and targets (see the section on blood glucose management).
▶ Symptoms, and the risk of hypoglycaemia and how it is treated.
▶ Management of special situations, such as driving.
▶ Communicating with the diabetes professional team (how often and how to contact them).
▶ Management of cardiovascular risk factors (see the section on control of cardiovascular risk).
▶ Implications for pregnancy and family planning advice (see NICE’s guideline on diabetes in pregnancy).
▶ How often they will have follow-up appointments, and what these will cover (including review of HbA1c levels, experience of hypoglycaemia, and annual reviews). [2004, amended 2015]
1.1.13 After the initial plan is agreed, implement it without inappropriate delay. Based on discussion with the adult with type 1 diabetes, modify the plan as needed over the following weeks. 
1.3 Education and information
1.3.1 Offer all adults with type 1 diabetes a structured education programme of proven benefit, for example, the DAFNE (dose adjustment for normal eating) programme. 
Full details of this section are available at: www.nice.org.uk/guidance/ng17/.
1.4 Dietary management
1.4.1 Offer carbohydrate counting training to adults with type 1 diabetes as part of structured education programmes for self-management (see the section on education and information). 
1.4.2 Consider carbohydrate counting courses for adults with type 1 diabetes who are waiting for a more detailed structured education programme or who are unable to take part in a standalone structured education programme. 
Glycaemic index diets
1.4.3 Do not advise adults with type 1 diabetes to follow a low glycaemic index diet for blood glucose control. 
1.4.4 Offer dietary advice to adults with type 1 diabetes about issues other than blood glucose control (such as managing weight and cardiovascular risk), as needed. 
1.6 Blood glucose management
HbA1c measurement and targets
1.6.1 Measure HbA1c levels every three to six months in adults with type 1 diabetes. 
1.6.2 Consider measuring HbA1c levels more often in adults with type 1 diabetes if their blood glucose control is suspected to be changing rapidly; for example, if their HbA1c level has risen unexpectedly above a previously sustained target. 
1.6.3 Measure HbA1c using methods calibrated according to International Federation of Clinical Chemistry (IFCC) standardisation. 
1.6.4 Tell adults with type 1 diabetes their HbA1c results after each measurement and have their most recent result available at consultations. Follow the principles on communication in NICE’s guideline on patient experience in adult NHS services. 
1.6.5 If HbA1c monitoring is invalid because of disturbed erythrocyte turnover or abnormal haemoglobin type, estimate trends in blood glucose control using one of the following:
▶ Fructosamine estimation.
▶ Quality-controlled blood glucose profiles.
▶ Total glycated haemoglobin estimation (if abnormal haemoglobins). 
1.6.6 Support adults with type 1 diabetes to aim for a target HbA1c level of 48mmol/mol (6.5 per cent) or lower, to minimise the risk of long-term vascular complications. 
1.6.7 Agree an individualised HbA1c target with each adult with type 1 diabetes. Take into account factors, such as their daily activities, aspirations, likelihood of complications, comorbidities, occupation, and history of hypoglycaemia. 
1.6.8 Ensure that aiming for an HbA1c target is not accompanied by problematic hypoglycaemia in adults with type 1 diabetes. 
1.6.9 Diabetes services should document the proportion of adults with type 1 diabetes who reach an HbA1c level of 53mmol/mol (7 per cent) or lower. 
Blood glucose targets
1.6.22 Advise adults with type 1 diabetes to aim for:
▶ A fasting plasma glucose level of 5-to-7mmol/litre on waking; and
▶ A plasma glucose level of 4-to-7mmol/litre before meals at other times of the day. 
1.6.23 Advise adults with type 1 diabetes who choose to measure after meals to aim for a plasma glucose level of 5-to-9mmol/litre at least 90 minutes after eating. (This timing may be different in pregnancy – for guidance on plasma glucose targets in pregnancy, see NICE’s guideline on diabetes in pregnancy.) 
1.6.24 Agree bedtime target plasma glucose levels with each adult with type 1 diabetes. Take into account the timing of their last meal of the day and the related insulin dose, and ensure the target is consistent with the recommended fasting level on waking (see recommendation 1.6.22). 
Preventing and managing hypoglycaemia
1.10.10 Explain to adults with type 1 diabetes that a fast acting form of glucose is needed for managing hypoglycaemic symptoms or signs in people who can swallow. [2004, amended 2015]
1.10.11 Adults with type 1 diabetes who have a decreased level of consciousness because of hypoglycaemia and so cannot safely take oral treatment should be:
▶ Given intramuscular glucagon by a family member or friend who has been shown how to use it (intravenous glucose may be used by healthcare professionals skilled in getting intravenous access).
▶ Checked for response at 10 minutes, and then given intravenous glucose if their level of consciousness is not improving significantly.
▶ Then given oral carbohydrate when it is safe to administer it, and put under continued observation by someone who has been warned about the risk of relapse. [2004, amended 2015]
1.10.12 Explain to adults with type 1 diabetes that:
▶ It is very common to experience some hypoglycaemic episodes with any insulin regimen.
▶ They should use a regimen that avoids or reduces the frequency of hypoglycaemic episodes, while maintaining the most optimal blood glucose control possible. 
1.10.13 Make hypoglycaemia advice available to all adults with type 1 diabetes, to help them find the best possible balance with any insulin regimen. (See the sections on insulin therapy and insulin delivery.) 
1.10.14 If hypoglycaemia becomes unusually problematic or increases in frequency, review the following possible causes:
▶ Inappropriate insulin regimens (incorrect dose distributions and insulin types).
▶ Meal and activity patterns, including alcohol.
▶ Injection technique and skills, including insulin resuspension if necessary.
▶ Injection site problems.
▶ Possible organic causes, including gastroparesis.
▶ Changes in insulin sensitivity (including drugs affecting the renin–angiotensin system and renal failure).
▶ Mental health problems.
▶ Previous physical activity.
▶ Lack of appropriate knowledge and skills for self-management. 
1.10.15 Manage nocturnal hypoglycaemia (symptomatic or detected on monitoring) by:
▶ Reviewing knowledge and self-management skills.
▶ Reviewing current insulin regimen, evening eating habits, and previous physical activity.
▶ Choosing an insulin type and regimen that is less likely to cause low glucose levels at night. [2004, amended 2015]
1.10.16 If early cognitive decline occurs in adults on long-term insulin therapy, then in addition to normal investigations consider possible brain damage from overt or covert hypoglycaemia, and the need to manage this. 
1.11 Ketone monitoring and managing diabetic ketoacidosis
Ketone self-monitoring to prevent diabetic ketoacidosis.
1.11.1 Consider ketone monitoring (blood or urine) as part of ‘sick day rules’ for adults with type 1 diabetes, to help with self-management of hyperglycaemia. 
1.13 Control of cardiovascular risk
1.13.1 Do not offer aspirin for the primary prevention of cardiovascular disease in adults with type 1 diabetes. 
Identifying cardiovascular risk
1.13.2 Assess cardiovascular risk factors annually, including:
▶ Estimated glomerular filtration rate (eGFR) and urine albumin:creatinine ratio (ACR);
▶ Blood glucose control;
▶ Blood pressure;
▶ Full lipid profile (including high-density lipoprotein [HDL] and low-density lipoprotein [LDL] cholesterol, and triglycerides);
▶ Family history of cardiovascular disease;
▶ Abdominal adiposity. [2004, amended 2015 and 2021]
1.13.3 For guidance on tools for assessing risk of cardiovascular disease in adults with type 1 diabetes, see the recommendations on full formal risk-assessment in NICE’s guideline on lipid modification. 
Interventions to reduce risk and manage cardiovascular disease
1.13.4 For guidance on the primary prevention of cardiovascular disease in adults with type 1 diabetes, see the section on primary prevention for people with type 1 diabetes in NICE’s guideline on lipid modification. 
1.13.5 Give adults with type 1 diabetes who smoke advice on stopping smoking and stop smoking services, including NICE guidance recommended therapies (see the NICE topic page on smoking and tobacco). Reinforce these messages annually for people who currently do not plan to stop smoking, and at all clinical contacts if there is a prospect of the person stopping. 
1.13.6 Advise adults who do not smoke never to start smoking. [2004, amended 2021]
1.13.7 Provide intensive management for adults who have had myocardial infarction or stroke, according to relevant non diabetes guidelines. For angina or other ischaemic heart disease, beta-blockers should be considered (for insulin use in these circumstances, see the section on caring for adults with type 1 diabetes in hospital). For guidance on secondary prevention of myocardial infarction, see NICE’s guideline on acute coronary syndromes. [2004, amended 2015]
Blood pressure management
1.13.8 In adults with type 1 diabetes aim for blood pressure targets as follows:
▶ For adults with a urine ACR less than 70mg/mmol, aim for a clinic systolic blood pressure less than 140mmHg (target range 120-to-139mmHg) and a clinic diastolic blood pressure less than 90mmHg.
▶ For adults with an ACR of 70mg/mmol or more, aim for a clinic systolic blood pressure less than 130mmHg (target range 120-to-129mmHg) and a clinic diastolic blood pressure less than 80mmHg.
▶ In adults aged 80 or more, whatever the ACR, aim for a clinic systolic blood pressure less than 150mmHg (target range 140-to-149mmHg) and a clinic diastolic blood pressure less than 90mmHg.
▶ Use clinical judgement for adults with frailty, target organ damage (damage to organs because of diabetes, for example, to nerves or eyes) or multimorbidity. See the recommendations on pharmacotherapy in NICE’s guideline on chronic kidney disease, and NICE’s guidelines on hypertension in adults and multimorbidity. [2004, amended 2022]
1.13.9 Discuss the following with adults with type 1 diabetes who have hypertension to help them make an informed choice:
▶ Reasons for the choice of intervention level;
▶ The substantial potential gains from small improvements in blood pressure control;
▶ Any possible negative consequences of therapy. [2004, amended 2015]
1.13.10 Start a trial of a renin-angiotensin system blocking drug as first-line therapy for hypertension in adults with type 1 diabetes. [2004, amended 2015]
1.13.11 Provide information to adults with type 1 diabetes on how lifestyle changes can improve their blood pressure control and associated outcomes, and offer help to achieve their aims in this area. 
1.13.12 Do not allow concerns over potential side-effects to inhibit advising and offering the necessary use of any class of drugs, unless side-effects become symptomatic or otherwise clinically significant. In particular:
▶ Do not avoid selective beta-blockers for adults on insulin if these are indicated;
▶ Low-dose thiazides may be combined with beta blockers;
▶ When prescribing calcium channel antagonists, only use long-acting preparations;
▶ Ask adults directly about potential side-effects of erectile dysfunction, lethargy and orthostatic hypotension with different drug classes. [2004, amended 2015]
1.13.13 This recommendation has been removed as the previous link to NICE’s guideline on chronic kidney disease no longer provides relevant information.
• Full Type 1 diabetes in adults: diagnosis and management (NG17) guideline is available at: www.nice.org.uk/ guidance/ng17/.
Irish diabetes clinical guidelines
There are a number of national guidelines for diabetes-related care published by the HSE’s National Clinical Programme for Diabetes, while the ICGP also published integrated care guidelines for the management of type 2 diabetes in general practice in 2016, which were developed in conjunction with the National Clinical Programme for Diabetes Working Group.
In relation to type 1 diabetes specifically, in 2018 the adult type 1 diabetes mellitus guideline was published (Adult type 1 diabetes mellitus National Clinical Guideline No. 17), which can be accessed here: www. hse.ie/eng/about/who/cspd/ncps/diabetes/ resources/adult-type-1-diabetes-mellitus.pdf.
The document was put together by a Guideline Development Group, supported by the HSE National Clinical Programme for Diabetes, and developed through contextualisation of NICE’s 2015 Type 1 diabetes in adults: Diagnosis and management NG17 guideline document.