When is dialysis indicated in patients with impaired renal function?

Indications for Dialysis Initiation in Impaired Renal Function

Dialysis should be initiated when patients develop signs and symptoms attributable to kidney failure, including serositis, acid-base or electrolyte abnormalities, pruritus, inability to control volume status or blood pressure, progressive deterioration in nutritional status refractory to dietary intervention, or cognitive impairment, which typically occurs at GFR between 5-10 mL/min/1.73m².1

Primary Indications Based on Clinical Symptoms

• Dialysis initiation should be based primarily on the assessment of signs and symptoms associated with uremia rather than on a specific level of kidney function 1
• Uremic symptoms requiring dialysis include nausea/vomiting, serositis (pericarditis, pleuritis), encephalopathy, and pruritus 1, 2
• Electrolyte abnormalities warranting dialysis include refractory hyperkalemia, severe metabolic acidosis (pH <7.2), and hyperphosphatemia unresponsive to medical management 3, 4
• Volume overload with respiratory compromise that is refractory to diuretics is a clear indication for dialysis initiation 1, 3

GFR-Based Considerations

• For adult patients, dialysis should be considered when weekly renal Kt/Vurea falls below 2.0, which approximates a GFR of about 10.5 mL/min/1.73m² 1
• For pediatric patients, dialysis should be considered when GFR is 9-14 mL/min/1.73m² and recommended when GFR is ≤8 mL/min/1.73m² 1
• The IDEAL study showed no mortality benefit to starting dialysis at higher GFR (10-14 mL/min/1.73m²) versus lower GFR (5-7 mL/min/1.73m²) 5, 2
• In asymptomatic patients with stage 5 CKD, dialysis may be safely delayed until GFR is at least as low as 5-7 mL/min/1.73m² if careful clinical follow-up is maintained 5

Specific Laboratory and Clinical Thresholds

• Blood urea nitrogen (BUN) >100 mg/dL with altered mental status 3
• Serum potassium >6.5 mmol/L refractory to medical management 4, 6
• Severe metabolic acidosis with bicarbonate <16 mEq/L despite oral bicarbonate supplementation 4
• Progressive malnutrition with declining serum albumin and body weight despite dietary intervention 1

Special Considerations

• Pregnant women with end-stage kidney disease should receive long frequent hemodialysis either in-center or at home 1
• Patients with CKD stage 4-5 and sepsis may require urgent dialysis if they develop refractory fluid overload despite careful fluid management 3
• For elderly patients, the decision to initiate dialysis should carefully weigh benefits against risks, as comorbidities and frailty may lead to worse outcomes 5

Monitoring Prior to Dialysis Initiation

• Patients approaching the need for dialysis should be monitored monthly for clinical status 1
• GFR can be estimated by averaging measured creatinine and urea clearances using timed urine collection 1
• Residual kidney function should be assessed every 3 months in patients approaching dialysis 1
• Patients should be referred to specialist kidney care services when GFR <30 mL/min/1.73m² or when the risk of kidney failure within 1 year is 10-20% or higher 1

Common Pitfalls to Avoid

• Relying solely on estimated GFR without considering clinical symptoms can lead to premature or delayed dialysis initiation 1, 5
• Delaying nephrology consultation when considering dialysis can lead to poor outcomes 3
• Failing to consider conservative management as an option for patients who choose not to pursue renal replacement therapy 1
• Neglecting to prepare patients psychologically and physically (vascular access creation) for dialysis in advance 1

Dialysis Modality Selection

• The decision regarding selection of dialysis modality should consider patient/family choice, patient size, medical comorbidities, and family support 1
• Patients should receive education about different renal replacement therapy options, including transplantation, peritoneal dialysis, and hemodialysis 1
• There are no significant differences in 5-year mortality between hemodialysis and peritoneal dialysis 2

By following these guidelines for dialysis initiation, clinicians can optimize outcomes while avoiding both premature initiation (which has not been shown to improve survival) and delayed initiation (which may lead to preventable complications of uremia).