How can hypoglycemia be prevented during dialysis in patients with diabetes?

Preventing Hypoglycemia During Dialysis

Use dialysate containing 90-100 mg/dL glucose and reduce insulin doses by 25-50% on dialysis days to prevent hypoglycemia, which occurs in up to 50% of diabetic patients during hemodialysis despite glucose-containing dialysate. 1, 2

Understanding the Problem

Hypoglycemia during dialysis is extremely common and dangerous, occurring in 46-52% of ambulatory diabetic patients on maintenance hemodialysis and is associated with increased mortality. 3 The problem is multifactorial:

• Glucose levels drop progressively during hemodialysis, reaching their lowest point at the end of the dialysis session (typically after 3 hours), followed by a glycemic peak after dialysis. 3
• Most hypoglycemic episodes are asymptomatic, making them particularly dangerous and difficult to detect without continuous monitoring. 2
• Even with dialysate containing 100-150 mg/dL glucose, 21% of patients still experience hypoglycemia, with sensor glucose levels falling well below the dialysate glucose concentration. 2

Dialysate Glucose Concentration Strategy

Use dialysate with 90-100 mg/dL glucose concentration as the standard approach:

• Dialysate with 90 mg/dL glucose prevents hypoglycemia without causing excessive hyperglycemia, whereas glucose-free or 55 mg/dL glucose dialysate fails to prevent hypoglycemic episodes. 4, 5
• Glucose-free dialysate should be avoided as it causes hypoglycemia in diabetic patients, particularly those with pre-dialysis glucose <140 mg/dL. 5
• Higher glucose concentrations (100-150 mg/dL) may be needed for patients with recurrent intradialytic hypoglycemia, though even these concentrations don't eliminate risk entirely. 2

Insulin Dose Reduction Protocol

Implement aggressive insulin dose reductions for dialysis patients:

For Type 1 Diabetes:

• Reduce total daily insulin dose by 35-40% when initiating dialysis. 1
• Further reduce basal insulin by 25% on pre-dialysis days to account for decreased insulin clearance. 1

For Type 2 Diabetes:

• Reduce total daily insulin dose by approximately 50% when starting dialysis. 1
• Consider basal-plus approach rather than basal-bolus regimens to minimize hypoglycemia risk. 1

Mechanistic Rationale:

• The kidney normally clears 30-80% of insulin, so dialysis patients have prolonged insulin action and reduced insulin degradation. 1
• Both insulin and glucose are removed during hemodialysis, with plasma insulin levels decreasing significantly as blood passes through the dialyzer. 6

Glucose Monitoring Strategy

Implement continuous glucose monitoring (CGM) as the preferred monitoring method:

• CGM should be used to detect asymptomatic hypoglycemia during and after dialysis sessions, as traditional monitoring misses most episodes. 3
• Monitor blood glucose before dialysis and at 1-2 hours into dialysis, as hypoglycemia symptoms are most common within 1-2 hours of starting dialysis (57.9% incidence). 7
• If blood glucose drops by >37.7% from baseline, take immediate preventive action, as this threshold has 84.6% specificity and 73% sensitivity for predicting hypoglycemia. 7

CGM Advantages in Dialysis:

• CGM metrics (mean glucose, GMI, time-in-range) are more reliable than HbA1c in dialysis patients, as HbA1c is falsely low due to anemia, erythropoietin use, and reduced red blood cell lifespan. 3
• Calibrate sensors after rapid volume changes during or immediately after hemodialysis using a hybrid CGM and glucose meter approach. 3

Glycemic Targets

Target more moderate fasting glucose levels of 110-130 mg/dL rather than aggressive targets:

• Very low HbA1c levels (≤5.4% or ≤35.5 mmol/mol) are associated with increased mortality in hemodialysis patients, creating a U-shaped mortality curve. 3
• Aim for HbA1c of 7-8% in dialysis patients with high comorbidity burden or hypoglycemia risk, rather than the standard <7% target. 3
• Patients with pre-dialysis glucose <140 mg/dL are at highest risk for intradialytic hypoglycemia and require closer monitoring. 5

Timing and Meal Considerations

Coordinate insulin dosing and meals around dialysis sessions:

• Reduce basal insulin by 25% the day before dialysis to prevent hypoglycemia during the session. 1
• Total daily insulin requirements may decrease by 15% post-dialysis, with a 25% reduction in basal insulin needs the day after dialysis compared to the day before. 3
• Monitor for post-dialysis hyperglycemia, which typically peaks 2.5 hours after dialysis ends. 3

Special Populations

Be aware that 15-30% of ESKD patients may experience "burn-out diabetes" requiring minimal or no insulin therapy. 1 These patients need particularly careful monitoring to avoid iatrogenic hypoglycemia from continued insulin therapy.

Critical Pitfalls to Avoid

• Never rely solely on HbA1c for glycemic management in dialysis patients, as it underestimates mean glucose levels and correlates poorly with actual glycemic control. 3
• Don't assume glucose-containing dialysate eliminates hypoglycemia risk—50% of patients still have sensor glucose levels drop below the dialysate glucose concentration. 2
• Avoid aggressive glycemic targets that increase hypoglycemia risk without mortality benefit in this population. 3
• Don't forget that hypoglycemia-related hospitalizations before dialysis initiation strongly predict higher mortality after starting dialysis. 3