When should dialysis be initiated in patients with impaired renal function and what are the key components of a dialysis regimen?

Dialysis Initiation and Key Components of Dialysis Regimens

Dialysis should be initiated when the glomerular filtration rate (GFR) falls below 15 mL/min/1.73 m², or earlier if there are specific complications of renal insufficiency that put the patient's life at risk, regardless of the absolute GFR value. 1

When to Initiate Dialysis

GFR-Based Criteria

• Primary threshold: GFR < 15 mL/min/1.73 m² 2, 1
• Average GFR at dialysis initiation in practice: 9.8 mL/min/1.73 m² 2, 1
• Different populations show variation in initiation thresholds:
  • Young/middle-aged adults: 7-9 mL/min/1.73 m² 2
  • Children and elderly: 10-10.5 mL/min/1.73 m² 2
  • Patients with significant comorbidities often start at higher GFR levels 1

Clinical Indications for Immediate Dialysis Initiation

Regardless of GFR, dialysis should be initiated immediately for 1:

1. Electrolyte disorders:

   • Severe hyperkalemia (>6.5 mmol/L or with ECG changes)
   • Severe hyponatremia/hypernatremia with neurological symptoms
   • Severe hypercalcemia with altered mental status or arrhythmias

2. Acid-base disorders:

   • Severe metabolic acidosis (pH <7.1 or bicarbonate <12 mEq/L)

3. Uremic manifestations:

   • Uremic encephalopathy
   • Uremic pericarditis
   • Pulmonary edema unresponsive to diuretics
   • Severe uncontrolled hypertension
   • Persistent nausea and vomiting attributed to uremia

4. Nutritional considerations:

   • Protein-energy malnutrition that persists despite optimal nutritional support 1

Key Components of Dialysis Regimens

1. Dialysis Adequacy Assessment

• Regular monitoring of dialysis adequacy using validated methods
• For patients with unusual creatinine generation (high or low), use methods independent of creatinine generation, such as measurement of creatinine and urea clearances 2

2. Residual Renal Function (RRF) Preservation

• Consider progressive dialysis initiation approach:
  • For patients with urea clearance ≥2.5 mL/min, starting with 2 sessions/week may help preserve RRF 3
  • This approach has shown lower rates of RRF decline (0.22 vs 0.89 mL/min/month) 3
  • Lower β2-microglobulin levels and reduced erythropoietin requirements observed with this approach 3

3. Vascular Access Planning

• Vascular access should be created when GFR falls below 20 mL/min/1.73 m² 4
• Early referral for vascular access creation is crucial, especially in transplant patients who may have limited access options due to previous thrombosis 4

4. Peritoneal Dialysis Considerations

• For patients choosing peritoneal dialysis, catheter placement should be scheduled at least 15 days before beginning training 4

5. Monitoring and Follow-up

• Regular assessment of:
  • Residual renal function
  • Nutritional status
  • Electrolyte balance
  • Acid-base status
  • Volume status
  • Blood pressure control

Special Considerations

Elderly Patients

• Decision to initiate dialysis should carefully weigh risks against benefits, considering quality of life 5
• Conservative care should be considered in appropriate cases 5

Transplant Patients

• All transplant patients should be considered as having chronic kidney disease even with normal GFR 4
• Transplant patients with graft dysfunction often start dialysis later with more uremic complications than first-time dialysis patients 4

Common Pitfalls to Avoid

1. Relying solely on eGFR for dialysis initiation:

   • Creatinine-based formulae are inaccurate in ESKD patients 5
   • Clinical symptoms and signs should guide decision-making alongside eGFR

2. Starting dialysis too early:

   • Early initiation (eGFR >10 mL/min/1.73 m²) has not shown mortality benefit 5
   • The IDEAL study demonstrated no advantage to early dialysis initiation 1, 5

3. Delayed referral to nephrology:

   • Late referral compromises pre-dialysis care and planning 5
   • Inadequate time for vascular access creation leads to higher catheter use

4. Overlooking nutritional status:

   • Failure to evaluate nutritional status can lead to delayed or inappropriate initiation of dialysis 1

5. Ignoring residual renal function:

   • RRF contributes significantly to total clearance and quality of life
   • Dialysis prescription should account for and aim to preserve RRF 3