What is the most appropriate approach for managing blood glucose in an 80-year-old female with type 2 diabetes mellitus (T2DM) on metformin (Metformin) and dapagliflozin (Dapagliflozin) prior to surgery?

Perioperative Blood Glucose Management for Elderly Diabetic Patient

Based on the American Diabetes Association (ADA) standards of care, dapagliflozin should be discontinued 3-4 days before surgery and metformin should be withheld on the day of surgery. Use basal-bolus insulin to manage blood glucose in the interim, with short-acting insulin as needed when NPO. 1

Medication Management Before Surgery

SGLT2 Inhibitors (Dapagliflozin)

• Must be discontinued 3-4 days before surgery 1
• This timing is critical as SGLT2 inhibitors can increase risk of diabetic ketoacidosis, especially during periods of fasting 2
• The FDA label for dapagliflozin specifically states to "withhold dapagliflozin for at least 3 days prior to major surgery or procedures associated with prolonged fasting" 2

Metformin

• Should be withheld on the day of surgery only 1
• Earlier recommendations to withhold metformin for 48 hours before surgery 3 have been superseded by more recent ADA guidelines

Other Oral Hypoglycemic Agents

• Withhold any other oral glucose-lowering agents on the morning of surgery 1

Insulin Management During the Perioperative Period

Insulin Regimen

• Use basal-bolus insulin regimen during the perioperative period 1, 4
• Give 75-80% of long-acting analog insulin dose 1
• Basal-bolus insulin regimens are associated with improved glycemic control and lower rates of perioperative complications compared to sliding-scale regimens 1, 4

Blood Glucose Monitoring

• Monitor blood glucose every 2-4 hours while the patient is NPO 1, 4
• Use short-acting or rapid-acting insulin as needed for hyperglycemia 1
• Target blood glucose range for the perioperative period should be 80-180 mg/dL (4.4-10.0 mmol/L) 1, 4

Rationale for This Approach

1. Safety concerns with SGLT2 inhibitors: Dapagliflozin must be discontinued 3-4 days before surgery to prevent potential diabetic ketoacidosis during the perioperative period, which can occur even with normal blood glucose levels 1, 2

2. Metformin considerations: Withholding metformin on the day of surgery is sufficient according to current ADA guidelines 1

3. Superiority of basal-bolus insulin: This approach provides better glycemic control than sliding-scale insulin alone, which has been associated with higher rates of hyperglycemia and complications 1

4. Hypoglycemia prevention: Basal-bolus regimen with appropriate dose reductions (75-80% of usual basal insulin) helps prevent dangerous hypoglycemia during the perioperative fasting period 1, 4

Special Considerations for Elderly Patients

• Elderly patients like Vivianne (80 years old) are at higher risk for hypoglycemia
• They may have impaired counterregulatory responses to hypoglycemia 1
• More frequent monitoring may be needed, especially during the night when hypoglycemia risk peaks (between midnight and 6:00 A.M.) 1
• Consider a 25% reduction in insulin dose the evening before surgery to reduce hypoglycemia risk 1

Common Pitfalls to Avoid

1. Using sliding-scale insulin alone: This approach is associated with poorer outcomes compared to basal-bolus regimens 1

2. Continuing SGLT2 inhibitors too close to surgery: This increases risk of diabetic ketoacidosis 1, 2

3. Withholding metformin for too long: Current guidelines only recommend withholding on the day of surgery, not 3 days before 1

4. Inadequate glucose monitoring: Blood glucose should be monitored every 2-4 hours while NPO 1

5. Overly aggressive glycemic targets: Targeting blood glucose <80 mg/dL increases hypoglycemia risk without improving outcomes 4