When to Initiate Dialysis Based on GFR
Dialysis should be initiated when GFR falls below 15 mL/min/1.73m² AND the patient develops uremic symptoms or signs, rather than at a specific GFR threshold alone. 1
Decision Algorithm for Dialysis Initiation
Primary Considerations
- GFR Threshold: <15 mL/min/1.73m² (CKD Stage 5)
- Clinical Symptoms/Signs: Presence of uremic symptoms is more important than GFR alone
When to Start Immediately (Regardless of GFR)
- Severe hydroelectrolytic disorders:
- Severe hyperkalemia
- Significant hypo/hypernatremia
- Hypercalcemia
- Severe metabolic acidosis
- Uremic encephalopathy
- Uremic pericarditis
- Pulmonary edema
- Severe hypertension unresponsive to medications 1
When to Consider Starting at Higher GFR (10-15 mL/min/1.73m²)
- Elderly patients (typically start at 10-10.5 mL/min/1.73m²) 2
- Pediatric patients (typically start at 10-10.5 mL/min/1.73m²) 2
- Significant comorbidities 2, 1
- Protein-energy malnutrition despite optimization attempts 2
When Dialysis Can Be Safely Delayed (GFR 5-7 mL/min/1.73m²)
- Asymptomatic patients
- Good nutritional status
- Stable electrolytes and acid-base balance
- Adequate volume control
- Close clinical follow-up 3
Evidence Analysis
The timing of dialysis initiation has evolved significantly. While earlier guidelines suggested starting at GFR of approximately 10 mL/min/1.73m² 2, more recent evidence shows no survival advantage to early initiation (GFR >10 mL/min/1.73m²) 4.
The IDEAL study demonstrated that early dialysis initiation (at higher GFR levels) does not improve outcomes compared to later initiation 1, 3. In fact, when accounting for lead-time bias, early initiation may be associated with worse outcomes 4.
The 2003 mean estimated GFR at dialysis initiation in the US was 9.8 mL/min/1.73m², with younger adults starting at 7-9 mL/min/1.73m² and elderly patients starting at 10-10.5 mL/min/1.73m² 2.
Important Caveats
Estimated GFR Limitations: eGFR formulas are less accurate at very low GFR levels, so clinical assessment is crucial 3
Residual Renal Function: Preserving residual kidney function is important; early dialysis may accelerate its loss 5
Access Planning: Vascular access planning should begin when GFR approaches 20 mL/min/1.73m² to ensure adequate time for maturation 6
Nutritional Assessment: Regular monitoring of nutritional status is essential; deteriorating nutrition despite intervention is an indication for dialysis 2, 1
Disparities in Care: Women, ethnic minorities, and uninsured patients are more likely to start dialysis late (GFR <5 mL/min/1.73m²), which may reflect reduced access to care 7
Monitoring Approach
- Regular assessment of:
- GFR (measured or estimated)
- Uremic symptoms
- Electrolyte balance
- Acid-base status
- Volume status
- Nutritional parameters
- BUN/Creatinine ratio (ratios >20:1 may indicate significant uremia requiring intervention) 1
In conclusion, while GFR <15 mL/min/1.73m² is the threshold to consider dialysis, the decision should be primarily driven by clinical symptoms and complications rather than by GFR alone. In asymptomatic patients with good clinical status, dialysis can be safely delayed until GFR reaches 5-7 mL/min/1.73m² with appropriate monitoring.