Introduction

This guidance is an update of 'type 1 diabetes' (NICE guideline CG15) and replaces the guidance for adults. The recommendations are labelled according to when they were originally published (see update information for details).

Type 1 diabetes affects over 370,000 adults in the UK. It results from destruction of the cells that normally make insulin. Loss of insulin secretion results in high blood glucose and other metabolic and haematological abnormalities, which have both short‑term and long‑term adverse effects on health. Over years, type 1 diabetes causes tissue damage which, if not detected and managed early, can result in disability: blindness, kidney failure and foot ulceration leading to amputation, as well as premature heart disease, stroke and death. The risk of all of these complications is greatly reduced by treatment that keeps circulating glucose levels to as near normal as possible, reducing tissue damage. Disability from complications that are not avoided can often be prevented by early detection and active management.

Type 1 diabetes is treated by insulin replacement, supported by active management of other cardiovascular risk factors, such as hypertension and high circulating lipids. Modern insulin replacement therapy aims to recreate normal fluctuations in circulating insulin concentrations. This supports a flexible lifestyle with minimal restrictions and, properly done, can improve blood glucose levels, reducing the risk of both structural complications and episodes of hypoglycaemia. Flexible insulin therapy usually involves self‑injecting multiple daily doses of insulin, with doses adjusted based on taken or planned exercise, intended food intake and other factors, including current blood glucose, which the insulin user needs to test on a regular basis. This self‑management needs the insulin user to have the skills and confidence to manage the regimen. One of the most important roles of healthcare professionals providing diabetes care to adults with type 1 diabetes is to ensure that systems are in place to provide informed, expert support, education and training for insulin users, as well as a range of other more conventional biomedical services and interventions.

Although type 1 diabetes in adults is not rare, it is not common enough that all healthcare professionals who deal with it are able to acquire and maintain all the necessary skills for its management. The aim of this guideline is to provide evidence‑based, practical advice on supporting adults with type 1 diabetes to live full, largely unrestricted, lives and to avoid the short‑term and long‑term complications of both the disease and of its treatment.

Reasons for the update

NICE last produced a guideline on type 1 diabetes in 2004. Since then, life expectancy for adults living with type 1 diabetes has increased, but it remains significantly shorter than for people without diabetes. There remain important deficiencies in care provision, most adults with type 1 diabetes have HbA1c above target levels, and rates of diabetic ketoacidosis (the acute complication of insulin deficiency) and renal failure have increased. This update focuses on areas where new knowledge and treatment opportunities have arisen in the last decade. These include improvements in technology to support better glucose levels, that should result in improved outcomes for adults with type 1 diabetes. These changes also present more challenges in terms of the diversity and complexity of the tools that can now be provided, and this guideline describes evidence‑based best practice for their deployment.

Topics updated from the 2004 guideline include:

  • diagnosing type 1 diabetes

  • structured education programmes

  • insulin preparations and regimens associated with improved glucose levels

  • needle length for insulin injections

  • new technologies for glucose monitoring and insulin delivery

  • managing acute painful neuropathy associated with rapid blood glucose control, erectile dysfunction in men and gastroparesis

  • primary prevention of cardiovascular disease.

The following topics were not included in 2004 and have been added:

  • new insulin formulations

  • identifying, quantifying and managing impaired awareness of hypoglycaemia

  • monitoring for thyroid disease

  • use of blood ketone measurement in preventing and monitoring diabetic ketoacidosis

  • carbohydrate counting and glycaemic index diets

  • referral criteria for transplantation therapies.

This guideline describes methods for achieving optimal outcomes for adults with type 1 diabetes and to inform service design and delivery. Its intended audience includes healthcare professionals involved in delivering services to adults with type 1 diabetes, service managers and commissioners, and adults with type 1 diabetes and their families.

Medicines

The guideline will assume that prescribers will use a medicine's summary of product characteristics to inform decisions made with individual patients.

This guideline recommends some medicines for indications for which they do not have a UK marketing authorisation at the date of publication, if there is good evidence to support that use. The prescriber should follow relevant professional guidance, taking full responsibility for the decision. The patient (or those with authority to give consent on their behalf) should provide informed consent, which should be documented. See the General Medical Council's Prescribing guidance: prescribing unlicensed medicines for further information. Where recommendations have been made for the use of medicines outside their licensed indications ('off‑label use'), these medicines are marked with a footnote in the recommendations.

  • National Institute for Health and Care Excellence (NICE)