What are the indications for dialysis in patients with impaired renal function, specifically those with end-stage renal disease (ESRD) or acute kidney injury (AKI)?

Dialysis: Overview and Indications

What is Dialysis?

Dialysis is a renal replacement therapy that artificially removes uremic toxins, excess fluid, and corrects electrolyte and acid-base disturbances when the kidneys can no longer maintain homeostasis. 1 The two primary modalities are hemodialysis (using an external filter to cleanse blood) and peritoneal dialysis (using the peritoneal membrane as a natural filter), with no significant differences in long-term mortality between them. 1

Absolute Indications for Dialysis (Life-Threatening)

Dialysis must be initiated immediately when any of the following life-threatening conditions occur, regardless of GFR or other laboratory values:

• Severe hyperkalemia with cardiac arrhythmias or ECG changes unresponsive to medical management 2
• Refractory metabolic acidosis that cannot be corrected with bicarbonate therapy 2
• Uremic pericarditis, encephalopathy, or bleeding diathesis 2
• Refractory volume overload causing pulmonary edema or compromising cardiac function despite maximal diuretic therapy 2

These absolute indications take precedence over all other considerations—delaying dialysis while attempting further medical optimization increases mortality. 2

Clinical Indications for Dialysis Initiation

Uremic Symptoms

Dialysis should be initiated when patients develop uremic symptoms that significantly impair quality of life: 2

• Intractable nausea and vomiting 2
• Severe pruritus 2
• Altered mental status or asterixis 2
• Serositis (pericarditis or pleuritis attributable to uremia) 2

Progressive Nutritional Deterioration

Dialysis is indicated when protein-energy malnutrition develops or persists despite vigorous attempts to optimize protein and energy intake, with no apparent cause other than uremia: 3, 2

• Declining serum albumin 3
• Decreasing edema-free body weight 2
• Deteriorating subjective global assessment 2

This is particularly critical because initiating dialysis with overt malnutrition is associated with increased mortality and morbidity. 3

GFR-Based Considerations

Chronic Kidney Disease

For CKD patients, consider dialysis initiation when GFR falls below 15 mL/min/1.73 m², though GFR alone should never be the sole criterion: 2

• Approximately 98% of U.S. patients begin dialysis at GFR <15 mL/min/1.73 m² 2
• A weekly Kt/V <2.0 suggests dialysis consideration 3, 2
• Exceptions to initiating dialysis despite low GFR include: stable or increasing edema-free body weight, adequate nutritional markers, and complete absence of uremic symptoms 2

The K/DOQI guidelines emphasize that dialysis initiation should be based on clinical trajectory, symptoms, and nutritional status rather than eGFR alone. 2

Acute Kidney Injury

For AKI, dialysis indications follow the RIFLE classification system: 3

• Risk: GFR decrease by 25% or serum creatinine increase by 1.5× baseline or urine output <0.5 mL/kg/h for 6 hours 4
• Injury: GFR decrease by 50% or serum creatinine increase by 2× baseline or urine output <0.5 mL/kg/h for 12 hours 4
• Failure: GFR decrease by 75% or serum creatinine >4 mg/dL (with acute rise ≥0.5 mg/dL) or urine output <0.3 mL/kg/h for 24 hours 4

A BUN level of 75 mg/dL is a useful indicator for dialysis in asymptomatic AKI patients, though clinical trajectory and prognosis are more important than numerical values. 5

Modality Selection Based on Clinical Context

Hemodynamically Stable Patients

Conventional intermittent hemodialysis is the standard treatment for hemodynamically stable patients with ESRD or AKI. 2, 1

Hemodynamically Unstable Patients

Continuous renal replacement therapy (CRRT) or prolonged intermittent renal replacement therapy is required for hemodynamically unstable patients, particularly those with coronary artery disease, to avoid precipitating cardiac ischemia or arrhythmias. 2

Home-Based Therapy

Peritoneal dialysis is performed at home and requires regular exchanges of dialysis fluid to maintain effective clearance of uremic toxins. 1 The dialysis fluid becomes saturated with waste products over time, necessitating regular changes to maintain the concentration gradient. 6

Critical Pitfalls to Avoid

• Never delay dialysis in patients with absolute indications while attempting hemodynamic optimization—this increases mortality 2
• Never use standard intermittent hemodialysis in hemodynamically unstable patients—this can precipitate cardiac ischemia or arrhythmias 2
• Never initiate dialysis based on eGFR alone—consider clinical trajectory, symptoms, and nutritional status 2
• Never assume a single abnormal creatinine represents chronic disease—repeat testing within days is mandatory 4

Alternative to Dialysis

Comprehensive conservative management should be offered to patients who decline renal replacement therapy, including advance care planning, symptom and pain management protocols, and psychological, spiritual, and culturally sensitive care. 2 This is a reasonable alternative to dialysis, particularly for individuals with limited life expectancy or severe comorbid conditions. 7

Transplantation Consideration

Preemptive kidney transplantation should be considered when GFR <20 mL/min/1.73 m² with evidence of progressive, irreversible CKD over 6-12 months, as transplantation typically yields the best patient outcomes. 2, 7