How should insulin glargine be administered to a patient with type 2 diabetes and severe renal impairment?

Insulin Glargine Administration in Type 2 Diabetes with Severe Renal Impairment

For patients with type 2 diabetes and severe renal impairment (eGFR <30 mL/min/1.73 m²), start insulin glargine at a reduced dose of 0.1-0.25 units/kg/day once daily, administered subcutaneously at the same time each day, with dose reductions of 50% from standard dosing to prevent hypoglycemia. 1, 2

Initial Dosing Strategy

Starting Dose Calculation:

• Use 0.1-0.25 units/kg/day for high-risk patients with severe renal impairment, elderly patients (>65 years), or those with poor oral intake 1
• This represents a 50% reduction from the standard type 2 diabetes starting dose of 0.1-0.2 units/kg/day 1
• For hospitalized patients with severe renal impairment on high-dose home insulin (≥0.6 units/kg/day), reduce the total daily dose by 20% upon admission 1

Administration Guidelines:

• Administer subcutaneously once daily at any time of day but at the same time every day 2
• Inject into the abdominal area, thigh, or deltoid, rotating injection sites within the same region 2
• Never administer intravenously, via insulin pump, or mix with other insulins 2

Foundation Therapy

Continue metformin unless contraindicated (eGFR <30 mL/min/1.73 m² is typically a contraindication), as metformin reduces total insulin requirements and provides superior glycemic control when combined with insulin 1, 3

For patients with eGFR <30 mL/min/1.73 m², metformin is generally contraindicated, so focus on insulin therapy alone or consider adding a GLP-1 receptor agonist, which is preferred in advanced CKD 4

Titration Protocol

Aggressive but Safe Titration:

• Increase by 2 units every 3 days if fasting glucose is 140-179 mg/dL 1
• Increase by 4 units every 3 days if fasting glucose is ≥180 mg/dL 1
• Target fasting plasma glucose: 80-130 mg/dL 1
• If hypoglycemia occurs without clear cause, reduce dose by 10-20% immediately 1

Critical Monitoring in Renal Impairment:

• Daily fasting blood glucose monitoring is essential during titration 1
• Monitor more frequently (every 4-6 hours) if oral intake is poor 1
• Insulin clearance decreases with declining kidney function, requiring closer monitoring for hypoglycemia 1

Special Considerations for Severe Renal Impairment

Physiologic Changes:

• Insulin clearance decreases with declining kidney function, increasing both hypoglycemia risk and duration of insulin activity 1
• For CKD Stage 5 (eGFR <15 mL/min/1.73 m²), reduce total daily insulin dose by 50% for type 2 diabetes 1

Glycemic Monitoring:

• HbA1c accuracy and precision decline with advanced CKD (G4-G5), particularly among dialysis patients 4
• Consider using glucose management indicator (GMI) derived from continuous glucose monitoring (CGM) when HbA1c is not concordant with directly measured blood glucose 4
• Daily glycemic monitoring with CGM or self-monitoring of blood glucose (SMBG) helps prevent hypoglycemia when using insulin 4

When to Add Prandial Insulin

Critical Threshold:

• When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, add prandial insulin rather than continuing to escalate basal insulin alone 1
• Start with 4 units of rapid-acting insulin before the largest meal, or use 10% of the current basal dose 1
• Titrate prandial insulin by 1-2 units or 10-15% every 3 days based on 2-hour postprandial glucose readings 1

Alternative Preferred Therapy in Advanced CKD

GLP-1 Receptor Agonists are Preferred:

• In adults with type 2 diabetes and advanced CKD (eGFR <30 mL/min/1.73 m²), a GLP-1 RA is preferred for glycemic management due to lower risk of hypoglycemia and for cardiovascular event reduction 4
• SGLT2 inhibitors have minimal glycemic effects at eGFR <30 mL/min/1.73 m² and are contraindicated in dialysis 5

Common Pitfalls to Avoid

Do not use standard dosing (0.1-0.2 units/kg/day) in severe renal impairment without dose reduction, as this significantly increases hypoglycemia risk 1

Do not continue escalating basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia, as this leads to overbasalization with increased hypoglycemia risk 1

Do not rely solely on HbA1c for glycemic monitoring in advanced CKD (G4-G5), as measurements have low reliability in dialysis patients 4

Do not delay dose reduction when hypoglycemia occurs—reduce immediately by 10-20% 1

Never administer insulin glargine intravenously or via insulin pump, and never dilute or mix with other insulins 2