Should I hold insulin glargine (long-acting insulin) when a patient decreases oral intake?

Should You Hold Insulin Glargine When a Patient Decreases Oral Intake?

No, do not hold insulin glargine completely—reduce the dose by approximately 40-50% of the usual basal insulin dose when a patient with type 1 diabetes decreases oral intake, as complete discontinuation risks diabetic ketoacidosis. 1, 2

Critical Distinction: Type 1 vs Type 2 Diabetes

For Type 1 Diabetes (Absolute Insulin Requirement)

• Never completely discontinue basal insulin in type 1 diabetes, even with minimal or no oral intake 2
• The American Diabetes Association explicitly recommends that basal insulin must continue to avoid diabetic ketoacidosis (DKA), even when patients are unable to ingest meals 1
• When oral food intake decreases in advanced type 1 diabetes, insulin dosing should be reduced but continued 1, 2

Specific Dosing Algorithm:

• Reduce to approximately 50% of the usual basal insulin dose for patients with poor nutritional intake 2
• The recommended minimum basal insulin dose during periods of poor intake is approximately 0.1-0.15 units/kg/day 1, 2
• Starting with a 40-50% reduction of the current glargine dose is appropriate given poor oral intake 2

For Type 2 Diabetes (Relative Insulin Deficiency)

• In hospitalized type 2 diabetes patients with poor oral intake, use basal insulin or a basal plus bolus correction regimen as the preferred treatment 1
• The starting insulin total daily dose should be reduced to 0.1-0.15 units/kg/day, given mainly as basal insulin 1
• Additional rapid-acting insulin analogs are administered only as correctional coverage for glucose levels >180 mg/dL before meals and at bedtime 1

Monitoring Requirements During Dose Reduction

• Increase blood glucose monitoring frequency during periods of poor oral intake to allow for further dose adjustments 2
• If blood glucose consistently falls below target threshold, further reduce the glargine dose by an additional 10-20% 2
• Bedside glucose monitoring should be performed every 4-6 hours in hospitalized patients not eating 1

Rationale: Why Basal Insulin Must Continue

Prevention of metabolic decompensation:

• The primary goal is to prevent hypoglycemia while maintaining enough basal insulin to prevent hyperglycemic crises 2
• Even with reduced oral intake, patients with type 1 diabetes require some basal insulin to prevent ketosis and DKA 2
• Small basal insulin doses delivered to dying patients may stabilize blood glucose and reduce complications of hyperglycemia 1

Physiologic considerations:

• Patients with decreased kidney function have increased risks for hypoglycemia due to decreased clearance of insulin and impaired kidney gluconeogenesis 1
• Approximately one-third of insulin degradation is carried out by the kidney, and impaired kidney function prolongs insulin half-life 1

Common Pitfalls to Avoid

• Do not completely discontinue basal insulin in type 1 diabetes under any circumstances—this is the most critical error that leads to DKA 1, 2
• Do not use sliding scale insulin (SSI) alone without basal coverage, as this approach does not account for basal insulin requirements and increases risk of both hypoglycemia and hyperglycemia 1
• Avoid premixed insulin formulations in hospitalized patients with poor oral intake, as they resulted in a threefold higher rate of hypoglycemia compared with basal-bolus regimens 1
• Do not use NPH insulin in patients with poor oral intake, as it has a peak action 8-12 hours after injection with higher risk of hypoglycemia compared to insulin analogs like glargine 1

Special Populations

Advanced disease or end-of-life care:

• In organ failure with reduced oral food intake, continue reduced but ongoing insulin 1
• In dying patients, a small basal insulin dose may stabilize blood glucose and reduce hyperglycemic complications 1

Chronic kidney disease:

• Patients with CKD stages 3-5 have prolonged insulin half-life and require closer monitoring with potential for further dose reductions 1
• Monitor glucose levels closely and reduce insulin doses as needed to avoid hypoglycemia 1