A 2024 consensus report from the American Diabetes Association (ADA) on hyperglycemic crises in adults with diabetes states that during the transition to maintenance insulin therapy in the hospital, to prevent recurrence of hyperglycemia or ketoacidosis, it is important to allow an overlap of 1-2 hours between the administration of subcutaneous insulin and the discontinuation of intravenous insulin, with basal insulin initiated at least 1-2 hours before stopping the IV infusion. While the report refers to basal insulin and notes that first-generation basal analogues and Neutral Protamine Hagedorn (NPH) insulin are frequently administered once daily, it does not explicitly mention long-acting insulin, though basal analogues are implied. Of note, this guidance applies to both diabetic ketoacidosis (DKA) and hyperglycemic hyperosmolar state (HHS), and the recommended transition techniques do not appear to differentiate between these conditions. [1]
According to the 2014 Society of Critical Care Medicine (SCCM) guidelines for the use of an insulin infusion in the management of hyperglycemia in critically ill patients, several models have been proposed for transitioning from intravenous to subcutaneous insulin; however, the supporting evidence is of low quality. Most transition models include basal, nutritional (prandial), and correction insulin components, with basal insulin, either long-acting every 24 hours (e.g., glargine) or intermediate-acting every 6-12 hours (e.g., NPH), recommended to be administered at least 2-4 hours before stopping the infusion to prevent rebound hyperglycemia. Total daily basal doses are often calculated from the preceding IV insulin requirements, with many authors reducing the dose to 80% of the estimated total daily dose to improve glucose control, although 60-70% has also been used successfully. When overlap is not feasible, a simultaneous injection of rapid-acting insulin (approximately 10% of the basal dose) may be given with the basal insulin at the time the infusion is stopped. The guidance does not specifically address DKA, suggesting that these transition principles may be applied to non-DKA hyperglycemia in critically ill patients. [2]
A 2012 article discusses insulin therapy for the management of hyperglycemia in hospitalized patients. At the time of this publication, the authors noted that subcutaneous insulin had not been formally studied in ICU patients and should generally be avoided in critically ill patients, particularly during hypotension or shock, because factors related to critical illness and the perioperative period can alter insulin absorption and increase the risk of overlapping doses, timing errors, and unexpected hypoglycemia. The article emphasizes that all patients with type 1 diabetes and most patients with type 2 diabetes receiving continuous IV insulin require transition to a subcutaneous insulin regimen. Several models for this transition have been proposed, generally involving extrapolating the 24-hour insulin requirement from the preceding 6–8 hours of IV insulin or using weight-based calculations, while considering nutritional status, concurrent medications, and ongoing glucose monitoring. Safe transition strategies typically assign approximately 80% of the total daily insulin dose into basal and prandial components aligned with the patient’s nutrition plan, with an overlap of 1–2 hours between IV discontinuation and subcutaneous basal insulin administration to prevent recurrent hyperglycemia. Basal insulin may be given as a single long-acting daily dose (e.g., glargine or detemir) or as two intermediate-acting NPH doses every 12 hours, and short- or rapid-acting insulin can be added as needed depending on caloric intake and glucose levels. For patients with mild stress hyperglycemia and low IV insulin requirements (≤1–2 U/h) at the time of transition, scheduled subcutaneous insulin may not be necessary, and correction doses alone may suffice. [3]