Dose-dependent relationship between SGLT2 inhibitor hold time and risk for postoperative anion gap acidosis: a single-centre retrospective analysis

Use of sodium-glucose transporter-2 (SGLT2) inhibitors has dramatically increased over the past decade. This medication class predisposes patients to euglycaemic diabetic ketoacidosis, particularly during times of physiologic stress, including fasting and surgery. Beyond case reports and series, a systematic description of perioperative metabolic effects of SGLT2 inhibitors is lacking.We examined the degree of anion gap acidosis, controlling for non-ketone anions, in patients undergoing surgery at Massachusetts General Hospital in 2016-22. We constructed a multivariable regression model incorporating known non-ketone contributors to the postoperative anion gap (albumin, lactate, estimated glomerular filtration rate, and preoperative anion gap), hold time, and interaction terms between hold time and three previously suggested risk factors for euglycaemic diabetic ketoacidosis: emergency surgery, cardiac surgery, and insulin use.In 463 patients on SGLT2 inhibitors, we observed a strong association between decreased hold time and postoperative anion gap (P<0.001 in a univariable analysis; -0.43, 95% confidence interval [-0.76 to -0.11] change in anion gap per day held, P=0.01 in a multivariable analysis). A significant interaction between hold time and emergency surgery was observed, whereas there was no apparent interaction with insulin use or cardiac surgery.These findings provide the first evidence that an anion gap acidosis, likely from ketoacids, develops in all patients who do not hold SGLT2 inhibitors before surgery rather than in an idiosyncratic few. If an SGLT2 inhibitor is unable to be stopped, postoperative monitoring of anion gap and serum ketones can help detect clinically significant euglycaemic diabetic ketoacidosis, particularly in those undergoing emergency surgery.