What is the best management approach for a patient with hyperglycemia (blood glucose 364 mg/dL) who is on a carbohydrate ratio of 1 unit of insulin per 7 grams of carbohydrates and is scheduled to receive dialysis today?

Management of Hyperglycemia in a Dialysis Patient

Immediate Insulin Dose Adjustment

For a blood glucose of 364 mg/dL in a dialysis patient, increase the insulin dose by 4 units immediately and reassess the carbohydrate ratio, as this level of hyperglycemia requires aggressive correction. 1

Critical Dialysis-Specific Considerations

• Insulin clearance is significantly reduced during hemodialysis, with plasma insulin levels decreasing by approximately 40-50% as blood passes through the dialyzer, regardless of dialysate glucose concentration 2
• Insulin requirements typically decrease by 30-50% in patients with advanced chronic kidney disease (CKD stage 5) due to reduced renal insulin clearance and decreased gluconeogenesis 1, 3
• The glucose content of the dialysate plays a critical role in preventing both acute hypoglycemia during dialysis and rebound hyperglycemia after dialysis 2

Insulin Dosing Algorithm for Dialysis Day

On dialysis days, reduce the total daily insulin dose by 20-50% to account for:

• Decreased insulin degradation by the kidneys 1
• Direct removal of insulin by the dialyzer 2
• Reduced gluconeogenesis in advanced CKD 1

For blood glucose ≥180 mg/dL, increase basal insulin by 4 units every 3 days until fasting glucose reaches 80-130 mg/dL, but monitor closely for hypoglycemia on dialysis days 1, 3

Carbohydrate Ratio Reassessment

The current ratio of 1:7 (1 unit per 7 grams of carbohydrate) may be insufficient given the blood glucose of 364 mg/dL:

• Calculate a new insulin-to-carbohydrate ratio using the formula: 450 ÷ total daily dose (TDD) 3
• If the patient's TDD is unknown, start with a more aggressive ratio of 1:10 and titrate based on 2-hour postprandial glucose readings 3
• Increase prandial insulin by 1-2 units or 10-15% every 3 days if postprandial glucose consistently exceeds 180 mg/dL 1, 3

Dialysis Day-Specific Protocol

Before dialysis:

• Check blood glucose immediately before the session 2
• If glucose >250 mg/dL, give 2 units of rapid-acting insulin; if >350 mg/dL, give 4 units 3
• Reduce scheduled basal insulin dose by 25% on dialysis days 3

During dialysis:

• Monitor for hypoglycemia symptoms, as insulin is actively removed by the dialyzer 2
• Ensure dialysate contains 100 mg/dL glucose to prevent intradialytic hypoglycemia 2

After dialysis:

• Expect rebound hyperglycemia in the evening hours, particularly in poorly controlled diabetes 2
• Check blood glucose 2-4 hours post-dialysis and give correction insulin if needed 2

Critical Threshold Warning

When basal insulin exceeds 0.5 units/kg/day without achieving glycemic targets, add prandial insulin rather than continuing to escalate basal insulin alone 1, 3. Signs of overbasalization include:

• Bedtime-to-morning glucose differential ≥50 mg/dL 3
• Hypoglycemia episodes 3
• High glucose variability 3

Monitoring Requirements

• Check fasting blood glucose daily during titration 1, 3
• Monitor blood glucose before each meal and at bedtime on non-dialysis days 1
• Check blood glucose every 4-6 hours on dialysis days due to increased hypoglycemia risk 1
• Reassess HbA1c every 3 months, recognizing that HbA1c may underestimate glycemic control in dialysis patients due to shortened red blood cell lifespan 1

Common Pitfalls to Avoid

• Do not use the same insulin doses on dialysis and non-dialysis days, as this leads to severe hypoglycemia during dialysis 1, 2
• Do not rely on HbA1c alone for glycemic assessment in dialysis patients, as it underestimates true glycemic control by approximately 1% 1
• Do not use glucose-free dialysate in poorly controlled diabetic patients, as this causes severe hyperglycemia in the evening hours 2
• Do not delay insulin dose adjustments, as 75% of hospitalized patients who experience hypoglycemia have no dose adjustment made before the next administration 3

Foundation Therapy

Continue metformin at maximum tolerated dose (up to 2000-2500 mg daily) unless contraindicated by severe renal impairment (eGFR <30 mL/min) 3. Metformin combined with insulin reduces total insulin requirements and provides complementary glucose-lowering effects 4.