Hypoglycaemia (Low Blood Sugar) in Adults With Diabetes and Adrenal Failure

PURPOSE OF THE STUDY The purpose of this study is to measure how often hypoglycaemia occurs in people who take steroid tablets for adrenal insufficiency and insulin for diabetes compared to individuals with adrenal insufficiency on steroid tablets without diabetes. To do this, participants will be given a continuous glucose monitoring (CGM) system, which is an effective and accurate way of measuring blood sugars throughout the day and night. This study will assess how often hypoglycaemia occurs, especially at night, and whether the type of steroid tablet people take affects how often hypoglycaemia happens. STUDY AIMS 1. To measure how often low blood sugars occur at night in people with both AI and insulin-treated diabetes using CGM, and in people without diabetes who are matched in age, sex and steroid replacement (hydrocortisone or prednisolone). 2. To compare the frequency of low blood sugars in people taking prednisolone for their AI versus those taking hydrocortisone. 3. To compare the patterns throughout the day for low blood sugars in those taking prednisolone versus those taking hydrocortisone. STUDY DESIGN This study will observe 16 adults with both insulin-treated diabetes and adrenal insufficiency and 16 adults without diabetes who are matched for age, sex and steroid replacement. The investigators will aim to recruit 32 participants in total. Participants will spend 30 days in the study. RECRUITMENT Recruitment will be undertaken in endocrinology and diabetes clinics at Imperial College Healthcare NHS Trust. Participant information sheets will be given to potential participants and following any questions, informed consent will be taken. Participants will be given as much time as they require (at least 24 hours) to decide whether or not to take part - this can vary on a per participant basis.