What is a suitable sliding scale insulin regimen for an insulin-dependent diabetic patient with impaired renal function on peritoneal dialysis?

Sliding Scale Insulin Regimen for an Elderly Insulin-Dependent Diabetic on Peritoneal Dialysis

For a 78-year-old, 103.2 kg insulin-dependent diabetic patient on peritoneal dialysis, the recommended sliding scale regimen should include a simplified approach with pre-meal blood glucose targets of 90-150 mg/dL and a conservative correction scale of 2 units rapid-acting insulin for blood glucose >250 mg/dL and 4 units for >350 mg/dL. 1

Baseline Insulin Considerations

Basal Insulin

• Administer basal insulin in the morning rather than at bedtime to improve monitoring
• Calculate initial basal dose conservatively due to renal impairment:
  • Reduce total daily insulin dose by approximately 35-40% compared to patients with normal renal function 1
  • For a patient on peritoneal dialysis, start with approximately 0.3 units/kg/day of basal insulin

Prandial Insulin

• Use a simplified approach for prandial coverage
• If currently on prandial insulin >10 units/dose: decrease by 50% and consider adding a non-insulin agent if appropriate 1
• If on prandial insulin ≤10 units/dose: consider discontinuing and using only correction insulin

Recommended Sliding Scale Regimen

Pre-meal Correction Scale:

• Blood glucose 150-250 mg/dL: No additional insulin
• Blood glucose >250 mg/dL: Add 2 units rapid-acting insulin
• Blood glucose >350 mg/dL: Add 4 units rapid-acting insulin 1

Monitoring Requirements:

• Check blood glucose before each meal and at bedtime
• Target range: 90-150 mg/dL before meals 1
• Adjust sliding scale every 2 weeks based on patterns

Special Considerations for Peritoneal Dialysis

1. Dialysate Glucose Absorption:

   • Peritoneal dialysis solutions contain glucose which can be absorbed systemically
   • Be cautious with icodextrin-containing solutions as they can interfere with certain glucose meters 1
   • Use GDH-NAD or GDH-FAD based glucose meters rather than GDH-PQQ or GO meters

2. Protein Requirements:

   • Patients on peritoneal dialysis should consume 1.0-1.2 g protein/kg/day 1
   • This higher protein requirement may affect carbohydrate intake and insulin needs

3. Hypoglycemia Risk:

   • Increased risk due to decreased renal gluconeogenesis and altered insulin clearance 2
   • Ensure patient has hypoglycemia awareness and treatment supplies

Adjustment Algorithm

1. Weekly Assessment:

   • If >50% of fasting glucose readings are above target: Increase basal insulin by 2 units
   • If >2 fasting glucose readings/week are <80 mg/dL: Decrease basal insulin by 2 units 1

2. Biweekly Assessment:

   • Review pre-meal glucose patterns every 2 weeks
   • If >50% of pre-meal readings are above target: Increase correction scale doses
   • If experiencing any hypoglycemia (<70 mg/dL): Decrease correction scale doses

Important Precautions

• Avoid rapid-acting or short-acting insulin at bedtime due to increased risk of nocturnal hypoglycemia 1
• Discontinue sliding scale when not needed daily
• Monitor for signs of fluid overload which may require insulin dose adjustments
• Consider the impact of peritoneal glucose absorption on blood glucose levels
• Use the shortest available needle length (4-mm pen or 6-mm syringe) to avoid intramuscular injection 3

This regimen prioritizes safety while providing adequate glycemic control, recognizing the increased vulnerability of elderly patients with renal failure to hypoglycemia and its potentially serious consequences.