Management of insulin therapy in acutely unwell patients with diabetes

• Aim for target CBG 6-10mmol/L (unless specified otherwise).
• Check HbA1c to provide a context for CBG patterns during acute illness: 

Sepsis, trauma, major surgery, steroid therapy

CBG usually rises:

• Increase insulin doses (see guidance on the management of hyperglycaemia in type 1 / pancreatic diabetes, or guidance on the management of hyperglycaemia in patients with type 2 diabetes on insulin).
• Consider checking ketones if CBG >14mmol/L (in type 1 diabetes) or >20mmol/L (in type 2 diabetes).

Fasting, recent weight loss, end-of-life, severe acute kidney injury

CBG usually falls:

• Reduce insulin doses (especially short / rapid-acting insulin).
• In a type 1 diabetic patient, never completely stop long-acting insulin. 

For more information on management of insulin in the perioperative period, please see the Perioperative Guideline for the Management of Diabetes. 

Guideline reviewed: February 2025

Page updated: November 2025