Clinically significant hypoglycaemia in hospitalised adults: A multicentre study of 1205 episodes in the United Kingdom

INTRODUCTION AND OBJECTIVES: Inpatient hypoglycaemia is a serious complication of diabetes therapy, yet real-world data on clinically significant episodes remain limited. The objectives of this study are (1) to describe the clinical and biochemical characteristics of clinically significant inpatient hypoglycaemia across multiple NHS sites, (2) to assess adherence to Joint British Diabetes Societies hypoglycaemia management guidelines, (3) to evaluate the applicability of International Hypoglycaemia Study Group (IHSG) classifications in hospitalised people with diabetes and (4) to identify gaps in care processes amenable to quality improvement (QI) interventions. METHODS: We conducted a retrospective cohort study across 11 UK centres, including all clinically significant hypoglycaemic episodes (IHSG Levels 2 and 3) between October 2023 and December 2024. Data on demographics, precipitants, clinical features, treatment, outcomes and subsequent therapeutic adjustments were analysed. RESULTS: We identified 1205 episodes from 674 people (mean age 72 years; 54.5% male; 74.6% with type 2 diabetes; median Charlson Comorbidity Index 6). Common precipitants included intercurrent illness (44.7%), fasting/missed meals (40.7%) and medication dosing errors (16.7%). Inpatient mortality occurred in 2.9% of Level 2 and 15.2% of Level 3 episodes. Episode characteristics varied by sex, diabetes type and centre. The IHSG classification system effectively stratified the risk of adverse outcomes. CONCLUSIONS: Clinically significant inpatient hypoglycaemia is associated with high mortality and substantial variation in care. The IHSG framework reliably predicts poor outcomes and may serve as a valuable framework for standardised risk stratification and service evaluation. Identification of common, modifiable risk factors highlights opportunities for systematic QI and surveillance.