What is the approach to incremental dialysis in patients with declining residual kidney function?

Incremental Dialysis Approach for Patients with Declining Residual Kidney Function

Incremental dialysis should be implemented when a patient's weekly Kt/Vurea falls below 2.0 or creatinine clearance falls into the range of 9-14 mL/min/1.73m², with gradual increases in dialysis dose as residual kidney function declines. 1

What is Incremental Dialysis?

Incremental dialysis is an individualized approach to dialysis initiation that:

• Starts with less frequent or lower-intensity dialysis sessions
• Gradually increases dialysis dose as residual kidney function (RKF) declines
• Maintains a target total solute clearance (combined kidney + dialysis)
• Prioritizes preservation of residual kidney function

When to Initiate Incremental Dialysis

Dialysis should be strongly considered when:

• Weekly Kt/Vurea falls below 2.0 (or creatinine clearance falls to 9-14 mL/min/1.73m²) 1
• Especially if any of these nutritional indicators show deterioration:

  • 6% involuntary reduction in edema-free body weight or <90% of standard body weight in <6 months

  • Reduction in serum albumin ≥0.3 g/dL to <4.0 g/dL (in absence of infection/inflammation)
  • Deterioration in Subjective Global Assessment by one category 1

Implementation of Incremental Peritoneal Dialysis

1. Initial Assessment:

   • Measure baseline residual kidney function (RKF)
   • Calculate Krt/Vurea (residual kidney component of urea clearance)
   • Perform Peritoneal Equilibration Test (PET) at end of first month 1

2. Prescription Approach:

   • Start with fewer exchanges or lower volumes
   • Ensure combined clearance (Krt/Vurea + Kpt/Vurea) remains ≥2.0 1
   • Example: If weekly Krt/Vurea is 1.6, provide peritoneal dialysis to achieve additional Kpt/Vurea of 0.4

3. Monitoring Schedule for Incremental PD:

   • First month: Measure PD fluid Kt/Vurea, PET, urine, Krt/Vurea, and CCr
   • Months 2,3,5: Additional urine and Krt/Vurea measurements
   • Months 4,6: Complete assessment (PD fluid Kt/Vurea, PET, Krt/Vurea, CCr) 1

Implementation of Incremental Hemodialysis

1. Initial Assessment:

   • Measure baseline RKF (Krt/Vurea)
   • Assess clinical status and absence of uremic symptoms

2. Prescription Approach:

   • May start with 1-2 sessions per week based on RKF
   • If weekly Krt/Vurea is 1.6, one weekly HD session must deliver equilibrated Kt/Vurea of 2.0 (difficult to achieve)
   • Two weekly sessions may be more realistic for this level of RKF 1
   • Adjust frequency and/or duration based on clinical parameters and RKF decline

3. Monitoring:

   • More frequent RKF monitoring is essential (every 2 months) 1
   • Measure delivered dialysis dose within first month
   • Monitor for signs of inadequate clearance

Benefits of Incremental Dialysis

• Preserves residual kidney function longer 2, 3
• Allows for better quality of life with fewer dialysis sessions
• Associated with comparable mortality outcomes to conventional approach 2, 4
• May reduce erythropoietin requirements 3
• Can defer full-dose dialysis by approximately one year 2
• Reduces healthcare costs and resource utilization 4

Adjusting Dialysis Dose as RKF Declines

1. Regular RKF Assessment:

   • Measure RKF every 2 months for incremental approach
   • Once weekly Kt/V falls below 0.1, RKF can be considered negligible 1

2. Dose Adjustment Triggers:

   • Declining urine output
   • Worsening laboratory parameters (elevated phosphorus, potassium, acidosis)
   • Development of uremic symptoms
   • Weight gain or fluid overload

3. Transition to Full Dialysis:

   • Gradually increase dialysis frequency/duration
   • For PD: Add exchanges or increase volumes
   • For HD: Progress from once to twice to thrice weekly

Pitfalls and Caveats

• Frequent RKF Monitoring: Failure to monitor RKF regularly can lead to inadequate total clearance 1
• Patient Selection: Not appropriate for all patients; those with severe uremic symptoms or complications should start with full-dose dialysis
• Communication: Patients must understand that dialysis intensity will need to increase as RKF declines
• Nutritional Management: Consider dietary modifications to support incremental approach, particularly on non-dialysis days 5
• Clinical Vigilance: Watch for signs of inadequate dialysis (malnutrition, hyperkalemia, fluid overload)

Conclusion

Incremental dialysis offers a patient-centered approach that can preserve RKF and improve quality of life. The key to success is careful monitoring of RKF and timely adjustments to dialysis prescription as kidney function declines, always maintaining a total Kt/Vurea ≥2.0.