What are the dangers of high interdialytic weight gain?

Dangers of High Interdialytic Weight Gain in Hemodialysis Patients

High interdialytic weight gain (IDWG) is associated with increased mortality, cardiovascular events, and reduced quality of life in hemodialysis patients, primarily due to volume overload, hypertension, and increased cardiac workload. 1, 2

Cardiovascular Complications

• Hypertension: Excessive IDWG leads to sodium and water retention, causing extracellular volume expansion and hypertension 1

  • Observational studies show both large IDWG and high ultrafiltration rates are associated with higher mortality 1
  • IDWG >3.5% of body weight is independently associated with increased cardiovascular mortality (26% higher risk) 2

• Heart Failure: IDWG ≥4% increases risk of fluid-overload hospitalization by 28-64% compared to IDWG of 2.5-3.99% 3

  • Volume expansion increases cardiac workload, leading to left ventricular hypertrophy and heart failure 1
  • Patients with IDWG >3.77% have significantly higher rates of congestive heart failure 4

• Myocardial Infarction: IDWG >3.5% increases risk of myocardial infarction by approximately 18% 2

Dialysis-Related Complications

• Intradialytic Hypotension: High IDWG necessitates higher ultrafiltration rates, which increases risk of:

  • Hypotensive episodes during dialysis 5
  • Muscle cramps and patient discomfort 5
  • Inadequate dialysis delivery when treatments must be shortened 1

• Ultrafiltration Rate Problems: When IDWG is excessive, ultrafiltration rates may exceed 10 mL/h/kg in 15-23% of patients 6

  • High ultrafiltration rates (>10 mL/h/kg) are associated with increased mortality 6
  • Attempts to remove excess fluid rapidly can lead to hypotension, seizures, and organ hypoperfusion 1

Long-Term Consequences

• Overall Mortality: IDWG ≥5.7% is associated with 23% increased risk of all-cause mortality compared to IDWG of 2.5-3.99% 3

• Vascular Access Complications: Intradialytic hypotension from rapid fluid removal increases risk of vascular access thrombosis 1

• Quality of Life Impairment: Symptoms related to fluid shifts (cramps, headaches, fatigue) reduce patient well-being 7

Risk Factors for High IDWG

Patient characteristics associated with higher IDWG include:

• Younger age
• Lower body mass index
• Longer dialysis vintage
• High blood pressure
• High dialysate sodium concentration 3, 6

Prevention Strategies

1. Sodium Restriction: Limit dietary sodium intake to reduce thirst and fluid intake 7

2. Dialysate Sodium Management: Avoid high dialysate sodium concentrations, particularly for patients with consistently elevated BP or high IDWG 1

   • Every 1 mEq/L increase in dialysate sodium is associated with 0.13% greater relative IDWG 3

3. Extended Dialysis Time: Longer, slower dialysis sessions allow for more gradual fluid removal with better hemodynamic stability 1

4. Patient Education: Counseling on fluid restriction and sodium intake limitations 5

Clinical Pitfalls to Avoid

• Overly Aggressive Ultrafiltration: Attempting to remove excessive fluid too quickly can cause intradialytic hypotension, seizures, and inadequate dialysis 1

• Ignoring Dry Weight Assessment: Regular reassessment of dry weight is essential, as incorrect targets can contribute to complications 5

• Focusing Only on Fluid Removal: Addressing underlying causes of thirst and xerostomia is also important 7

• Overlooking Sodium Intake: High sodium intake drives thirst and fluid consumption between dialysis sessions 1

High IDWG represents a significant clinical challenge that requires a comprehensive approach focusing on patient education, dietary sodium restriction, appropriate dialysate sodium concentration, and individualized dry weight assessment to reduce cardiovascular risk and improve outcomes.