When is dialysis indicated in patients with impaired renal function?

Indications for Dialysis in Patients with Impaired Renal Function

Dialysis should be initiated when patients develop uremic symptoms, metabolic abnormalities, or volume overload that cannot be managed with medical therapy, rather than based solely on a specific GFR threshold. 1

Primary Indications for Dialysis

Dialysis is indicated when one or more of the following conditions are present:

• Uremic symptoms and signs:

  • Serositis (pericarditis, pleuritis)
  • Encephalopathy (confusion, seizures, coma)
  • Peripheral neuropathy
  • Bleeding diathesis
  • Pruritus refractory to medical management

• Metabolic derangements:

  • Persistent hyperkalemia (>6.5 mEq/L) unresponsive to medical therapy
  • Severe metabolic acidosis (pH <7.2 or bicarbonate <15 mEq/L)
  • Hyperphosphatemia with symptomatic hypocalcemia

• Volume status issues:

  • Volume overload unresponsive to diuretics
  • Pulmonary edema
  • Hypertension refractory to medication

• Nutritional deterioration:

  • Progressive protein-energy wasting despite dietary intervention 1

GFR Considerations

While symptoms should guide dialysis initiation, GFR values can provide context:

• Dialysis is typically initiated when GFR falls to 5-10 mL/min/1.73m² in symptomatic patients 1, 2
• Early dialysis initiation (GFR >10 mL/min/1.73m²) has not shown mortality benefit 3
• In asymptomatic patients, dialysis may be safely delayed until GFR reaches 5-7 mL/min/1.73m² with careful monitoring 3
• A weekly renal Kt/Vurea <2.0 (approximately equivalent to GFR of 10.5 mL/min/1.73m²) may warrant dialysis unless the patient has:
  • Stable nutritional status
  • No uremic symptoms
  • No metabolic complications 1

Special Populations

Diabetic Patients

• Consider earlier initiation of dialysis than in non-diabetic patients 1

Pregnant Women

• Require more intensive dialysis (long frequent hemodialysis) 1

Elderly Patients

• Decision should carefully weigh benefits against risks of dialysis
• Conservative management may be appropriate in some cases with significant comorbidities 3

Modality Selection

Once the decision to initiate dialysis is made, modality selection should consider:

1. Hemodialysis: Preferred for:

   • Severe hyperkalemia requiring rapid correction
   • Severe metabolic acidosis
   • Uremic encephalopathy
   • Pericarditis

2. Peritoneal Dialysis: Consider for:

   • Hemodynamically unstable patients
   • Patients with difficult vascular access
   • Those preferring home-based therapy

3. Continuous Renal Replacement Therapy (CRRT): Indicated for:

   • Hemodynamically unstable ICU patients
   • Patients with increased intracranial pressure
   • Management of severe fluid overload 2

Pre-Dialysis Planning

For optimal outcomes, preparation should begin at CKD stage 4 (GFR <30 mL/min/1.73m²):

• Patient education about kidney failure treatment options
• Timely vascular access creation (ideally 3-6 months before anticipated need)
• Evaluation for kidney transplantation when appropriate 1

Monitoring Approach

For patients approaching dialysis threshold:

1. Monthly assessment of:

   • Uremic symptoms
   • Electrolytes and acid-base status
   • Volume status
   • Nutritional parameters

2. More frequent monitoring (every 1-2 weeks) when GFR <10 mL/min/1.73m²

3. Immediate evaluation for any acute deterioration in symptoms or laboratory values

Common Pitfalls to Avoid

• Relying solely on eGFR: Creatinine-based formulas become increasingly inaccurate at very low GFR levels 3

• Delaying dialysis too long: Can lead to uremic complications, malnutrition, and worse outcomes

• Starting dialysis too early: May unnecessarily expose patients to dialysis-related complications without mortality benefit 3

• Inadequate pre-dialysis planning: Results in emergency dialysis initiation with temporary vascular access and higher complication rates

• Neglecting conservative management option: For some patients, especially frail elderly with multiple comorbidities, conservative management may provide better quality of life than dialysis 1

The decision to initiate dialysis should ultimately be a shared decision between the physician, patient, and family members, tailored to the individual's clinical condition, preferences, and quality of life considerations.