Will blood glucose levels rise in patients with diabetes undergoing dialysis, particularly those receiving glucose-containing dialysate?

Blood Glucose Changes During and After Dialysis

Blood glucose typically falls during hemodialysis, reaching its lowest point at the end of the dialysis session, followed by a rebound rise (hyperglycemia) in the hours after dialysis ends. 1

Glucose Dynamics During Hemodialysis

During the Dialysis Session

• Glucose levels progressively decline throughout hemodialysis, with the nadir occurring at the end of the 4-hour treatment session 1, 2
• The mean blood glucose during dialysis is significantly lower compared to pre-dialysis levels (p = 0.004) 2
• On dialysis days, mean glucose levels are substantially lower than on non-dialysis days (95 ± 12.7 mg/dL vs 194 ± 76.8 mg/dL, p = 0.013) 2
• Hypoglycemia during dialysis is extremely common, occurring in 46-52% of ambulatory diabetic patients on maintenance hemodialysis 3

After the Dialysis Session

• A paradoxical hyperglycemic rebound occurs several hours after hemodialysis completion, typically peaking approximately 2.5 hours post-dialysis 1, 3, 4
• This post-dialysis hyperglycemia occurs via a mechanism similar to the Somogyi effect, combined with insulin resistance 4
• Blood glucose levels rise significantly from the time before dinner until bedtime on hemodialysis days compared to non-dialysis days 5

Mechanisms Explaining These Changes

Why Glucose Falls During Dialysis

The decline in glucose during hemodialysis results from multiple simultaneous mechanisms 1, 4:

• Decreased gluconeogenesis by the remnant kidneys 1, 4
• Increased erythrocyte glucose uptake during the hemodialysis procedure 1, 3
• Glucose loss to the dialysate (particularly with glucose-free or low-glucose dialysate) 4, 6
• Impaired insulin clearance by the kidneys, leading to prolonged insulin action 1, 3
• Reduced insulin degradation due to uremia 1, 3
• Nutritional deprivation common in dialysis patients 1, 3
• Impaired counterregulatory hormone responses (cortisol, growth hormone) 1

Why Glucose Rises After Dialysis

• The hyperglycemic rebound occurs through counterregulatory mechanisms triggered by the preceding hypoglycemia 4
• Insulin resistance develops in the post-dialysis period 4
• Total daily insulin requirements decrease by approximately 15% post-dialysis 3, 7

Impact of Dialysate Glucose Concentration

The main determinant of plasma glucose levels during and after hemodialysis is the glucose concentration of the dialysate 1:

Glucose-Free Dialysate (0 mmol/L)

• Results in more pronounced hypoglycemia during dialysis 8, 6
• Post-dialysis blood glucose averages 5.74 ± 1.82 mmol/L 6
• 30% of patients develop blood glucose <4.44 mmol/L (80 mg/dL) 6
• 48.33% of patients experience hunger during dialysis 6
• Creates a catabolic state similar to fasting 4

Standard Glucose-Containing Dialysate (5.55 mmol/L or 100 mg/dL)

• Reduces but does not eliminate the risk of hypoglycemia 8, 6
• Post-dialysis blood glucose averages 7.80 ± 2.59 mmol/L 6
• Only 1.67% of patients develop blood glucose <4.44 mmol/L 6
• 28.33% of patients experience hunger during dialysis 6

Higher Glucose Dialysate (11 mmol/L or 200 mg/dL)

• Previously used high-glucose dialysate solutions (up to 1600 mg/dL) led to hyperglycemia 1
• Dialysate with 11 mmol/L glucose results in fewer hypoglycemic and hypotensive episodes compared to 5.5 mmol/L 8
• Does not adversely affect HbA1c, lipid metabolism, or hepatic function in short-term studies 8

Clinical Monitoring Recommendations

Timing of Glucose Checks

The National Kidney Foundation recommends monitoring glucose at minimum: pre-hemodialysis, mid-hemodialysis (2 hours), end of hemodialysis, and 2-3 hours post-hemodialysis 7

Preferred Monitoring Method

• Continuous glucose monitoring (CGM) is the preferred method to detect asymptomatic hypoglycemia during and after dialysis, as traditional finger-stick monitoring misses most hypoglycemic episodes 1, 3, 7
• CGM metrics (mean glucose, GMI, time-in-range) are more reliable than HbA1c in dialysis patients 1

Critical Pitfalls to Avoid

• Never rely solely on HbA1c for glycemic assessment in dialysis patients, as it underestimates mean glucose levels due to anemia, erythropoietin use, and reduced red blood cell lifespan 1, 3
• Avoid aggressive glycemic targets that increase hypoglycemia risk without mortality benefit 3, 7
• Target fasting glucose of 110-130 mg/dL rather than tighter control, as very low HbA1c creates a U-shaped mortality curve in hemodialysis patients 3, 7
• Aim for HbA1c of 7-8% in dialysis patients rather than the standard <7% target 3, 9