Metabolism and Target Organ Damage

Abstract

People with diabetes mellitus (DM) undergo more elective surgery than those without DM; however, up to half of the patients are undiagnosed when referred for surgery. This is an opportunity to intervene and instigate a management plan. Preoperative strategies may vary based on coexisting medical diseases such as obesity and the availability of resources with the aim of achieving glycaemic control while also treating coexisting conditions. In the context of obesity, there is substantial overlap in some of the treatment strategies. Guidelines, such as those from the UK Centre for Perioperative Medicine, suggest target glycated haemoglobin levels, preoperative fasting blood glucose levels, and when to defer an elective operation or instigate treatment to proceed if deemed safe. Preoperatively glycaemic control is often achieved pharmacologically, and newer agents, including glucagon-like peptide one receptor agonists (GLP1-RA) and sodium-glucose co-transporter 2 (SGLT2) inhibitors, are emphasised in the preoperative management of diabetes mellitus, particularly if obesity is also present. A very low-energy diet is an underutilised but well-evidenced method of achieving both glycaemic control and weight loss with a particularly dominant effect on liver fat which is helpful for people who are due to undergo abdominal surgery. Bariatric-metabolic procedures are of growing interest as bridging interventions to surgery and are more commonly used for obesity, but they also have a well-recognized impact on the improvement and remission of DM. This review gives an overview of the necessity of preoperative identification of DM and strategies for management. Intra-operative glycaemic control is also discussed, and the role of stress hyperglycaemia perioperatively.