RecruitingInterventional

Hypoglycemia in type 1 diabetes

Living with type 1 diabetes requires careful management of blood sugar levels. Over time, some people stop feeling the usual early warning signs of low blood sugar (a 'hypo'), such as sweating or shaking. This is known as impaired hypo awareness, and it can increase the risk of severe, dangerous hypos. The CLEAR clinical trial is testing different ways to help people stay safe. It compares hybrid closed-loop systems—often called 'artificial pancreases', which automatically adjust insulin using a sensor and pump—with structured education programmes designed to help people recognise hypo patterns. The study lasts two years and is recruiting in several centres worldwide, including Leicester and Sheffield in the UK. Participants attend regular clinic checks and remote catch-ups to see which approach works best to prevent severe hypos and restore hypo awareness.

At a glance

Status

Recruiting

Sponsor

National Institute of Diabetes and Digestive and Kidney Diseases

Enrolment target

324

Start

17 Sep 2025

Estimated completion

30 Jun 2027

Type 1 diabetes with impaired awareness of hypoglycemia

What is this study about?

When you have type 1 diabetes, your blood glucose (sugar) can sometimes drop lower than normal. This is known as hypoglycemia, or a 'hypo'. Most people notice early warning signs like shakiness, sweating, hunger, or a pounding heart, giving them time to eat or drink fast-acting sugar. However, after living with diabetes for many years, around one in four people stop feeling these early signals. This is called impaired awareness of hypoglycemia. Without warning signs, blood sugar can drop to dangerous levels, leading to confusion, fainting, or needing emergency help from others.

The CLEAR study wants to find out the best way to help people regain their awareness or protect them from severe hypos. Researchers are comparing two main approaches: advanced diabetes technology and specialised educational support.

The technological approach uses a 'hybrid closed-loop' system, commonly called an artificial pancreas. This combines a continuous glucose monitor (CGM) under the skin, an insulin pump, and smart computer software that automatically adjusts insulin doses day and night. The educational approach uses structured training sessions to help people understand their personal glucose patterns, challenge habits, and rebuild awareness of low blood sugar.

By comparing these methods over two years, the study team hopes to discover which strategy—or combination of strategies—offers the best protection and quality of life for people living with long-term type 1 diabetes.

Key takeaways

Tests whether smart insulin devices or education programmes best prevent dangerous low blood sugar.
Aimed at adults who have had type 1 diabetes for 10+ years and cannot feel hypo warning signs.
Runs for two years, involving nine clinic visits and 11 phone or video calls.
UK centres include Leicester and Sheffield.
Taking part is voluntary and will not affect your standard NHS diabetes care.

Who may be eligible?

This trial is open to adults aged 18 to 75 who have lived with type 1 diabetes for at least 10 years. To take part, you must have difficulty sensing when your blood sugar drops low (impaired hypo awareness), which the study team can check using standard questionnaires.

You might not be able to join if you have certain other health issues, such as moderate to severe kidney disease, significant liver problems, untreated heart symptoms, or skin conditions that make wearing glucose sensors difficult. People taking steroid medications, those who have had certain stomach surgeries, or people with a history of substance misuse may also be excluded.

Additionally, the study is not suitable for anyone who is currently pregnant or planning a pregnancy during the trial period. Because the learning sessions and memory tests are currently only validated in English, participants must be able to speak and read English comfortably.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

I am aged between 18 and 75.
I have had type 1 diabetes for at least 10 years.
I often miss the early warning signs of low blood sugar (hypos).
I am not pregnant and not planning to become pregnant in the next two years.
I do not have severe kidney or liver disease.
I can comfortably read and speak English.

Answer every question to see your result.

What does participation involve?

If you take part, you will be enrolled in the study for a total of 24 months (two years). At the start, you will be assigned to a specific treatment plan: either using the automated insulin system, taking part in the education programme, or a mix of approaches. You will follow this plan for the first 12 months. At the one-year mark, the team will check how well the approach has worked for you. If it has helped reduce your hypos, you will stay on it for year two. If not, the team may switch you to an alternative approach.

Over the two years, you will attend nine in-person visits at a hospital clinic (such as Leicester or Sheffield in the UK) and take part in 11 telephone or video check-ins. During these appointments, doctors and nurses will monitor your health, take routine blood samples, review your glucose readings, and ask you to fill in questionnaires about your daily life and hypo symptoms.

Potential risks and benefits

Taking part may help you gain better control over your blood sugar levels and discover practical ways to avoid severe hypos. You will also receive close, regular care from diabetes specialists. However, there are some risks to consider. Wearing a sensor or pump cannula can sometimes cause skin redness, itching, or minor irritation. Blood tests may cause mild bruising or temporary discomfort, and there is always a general risk of experiencing high or low blood sugar while adjusting your routine. Joining the study is entirely your choice, and you can withdraw at any time without giving a reason and without your normal NHS care being affected.

Locations (9)

University of Leicester
Approximate
Leicester, England
University of Sheffield
Approximate
Sheffield, England
University of California, San Diego
Approximate
La Jolla, CA, United States of America
AdventHealth
Approximate
Orlando, Florida, United States of America
University of Kentucky
Approximate
Lexington, Kentucky, United States of America
University of Minnesota
Unverified
Minneapolis, MN, United States of America
University of Pennslyvania
Unverified
Philadelphia, United States of America
University of Melbourne
Unverified
Fitzroy, Victoria, Australia
The Kids Research Institute Australia
Unverified
Nedlands, Australia

Common questions

What is a hybrid closed-loop system?

It is a wearable system often called an 'artificial pancreas'. A small sensor under the skin reads your sugar levels and tells an insulin pump how much insulin to give automatically, though you still enter your meals manually.

Where in the UK is the trial taking place?

In the UK, the study is recruiting at hospital sites linked with the University of Leicester and the University of Sheffield.

Will taking part cost me anything?

No, you do not pay to take part. Study equipment, education, and trial appointments are provided free of charge, and sites may assist with travel expenses.

What happens if my assigned treatment is not helping?

The study checks your progress after 12 months. If your hypo awareness has not improved or you are still having issues, the team can switch you to an alternative study option for your second year.

Can I leave the study early if I change my mind?

Yes. Taking part is completely voluntary. You are free to leave the trial at any point, and your standard medical care will continue as normal.

How to find out more

Abid Kazi

akazi@pennstatehealth.psu.edu +1 (0)717 531 0003, Ext 320036 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.