What are the indications for dialysis in patients with impaired renal function?

Indications for Dialysis in Patients with Impaired Renal Function

Dialysis should be initiated when GFR falls below 15 mL/min/1.73 m² AND specific uremic symptoms or complications develop, rather than based on GFR alone, as early initiation at higher GFR levels provides no survival benefit and may cause harm. 1

GFR-Based Thresholds

Conservative management should continue until GFR decreases to <15 mL/min/1.73 m² unless specific clinical indications exist. 2

• The theoretical optimal GFR for dialysis initiation is approximately 10 mL/min/1.73 m², with actual mean GFR at initiation being 9.8 mL/min/1.73 m². 2

• Younger and middle-aged adults typically start at lower GFR values (7-9 mL/min/1.73 m²), while children and elderly patients start at higher values (10-10.5 mL/min/1.73 m²). 2, 1

• Early dialysis initiation (GFR >10 mL/min/1.73 m²) in asymptomatic patients provides no survival advantage when corrected for lead-time bias and may accelerate loss of residual kidney function. 1, 3

• Dialysis may be safely deferred even when GFR <10 mL/min/1.73 m² (potentially as low as 5-7 mL/min/1.73 m²) if patients remain asymptomatic with stable nutritional parameters. 1, 3

Absolute Clinical Indications (Override GFR Threshold)

Dialysis must be initiated regardless of GFR when any of the following are present:

Uremic Complications

• Uremic pericarditis (pericardial rub or effusion). 2, 1
• Uremic encephalopathy (altered mental status, asterixis, seizures). 1
• Uremic bleeding diathesis unresponsive to medical management. 2, 1
• Uremic neuropathy (peripheral or autonomic). 2, 1

Fluid and Electrolyte Derangements

• Volume overload refractory to diuretic therapy (pulmonary edema, severe hypertension). 2, 1
• Uncontrolled hypertension despite maximal medical management. 2, 1
• Severe hyperkalemia unresponsive to medical therapy. 1
• Severe metabolic acidosis refractory to bicarbonate supplementation. 1

Nutritional Deterioration

• Protein-energy malnutrition that develops or persists despite vigorous attempts to optimize protein and energy intake, with no apparent cause other than low nutrient intake. 2, 1
• Progressive decline in edema-free body weight. 1
• Serum albumin decline with falling lean body mass <63%. 1
• Intractable nausea and vomiting leading to inadequate oral intake. 1

Critical Caveats in GFR Estimation

When Standard GFR Estimates Are Unreliable

Use measured creatinine and urea clearances (24-hour urine collection) rather than estimated GFR in these situations: 2

• Low creatinine generation: Elderly patients, severe malnutrition, amputation, muscle-wasting diseases, vegetarian diet. 2
• High creatinine generation: Unusually muscular individuals, high meat intake. 2
• Altered tubular secretion: Cimetidine, trimethoprim use (decreased secretion); advanced liver disease (increased secretion). 2

Risks of Dialysis That Justify Conservative Management

Dialysis is not innocuous and imposes significant burdens that must be weighed against benefits: 2

• Hemodialysis-related hypotension may accelerate loss of residual kidney function, particularly with HD. 2, 1
• Vascular access complications (infection, thrombosis, steal syndrome). 1
• Does not replace all kidney functions (endocrine, metabolic). 2
• Significant burden on patient, family, and healthcare system. 2, 1

Decision-Making Framework

The timing of dialysis initiation represents a compromise designed to maximize quality of life by extending the dialysis-free period while avoiding life-threatening complications. 2, 1

Factors Favoring Earlier Initiation

• Presence of any absolute clinical indication listed above. 2, 1
• Inability to maintain adequate nutrition despite conservative management. 2, 1
• Poor vascular access options requiring early planning. 2, 1
• Transplant candidacy (may optimize timing for preemptive transplant). 2

Factors Allowing Delayed Initiation

• Complete absence of uremic symptoms. 1, 3
• Stable or increasing edema-free body weight. 1
• Adequate nutritional parameters (albumin, protein intake). 1
• Good adherence to dietary restrictions and medications. 2

Common Pitfalls to Avoid

• Do not initiate dialysis based solely on a GFR number without clinical symptoms, as this provides no benefit and may cause harm. 1, 3

• Do not rely on serum creatinine alone—always use validated GFR estimating equations or measured clearances. 2

• Recognize that patients with more comorbidities tend to start at higher GFR levels, but this reflects their frailty rather than benefit from early initiation. 2, 1

• Monitor nutritional status closely when GFR falls below 50 mL/min, as spontaneous protein and energy intake decline progressively. 2

• Consider that MDRD equation may overestimate GFR at very low levels—a MDRD of 19.7 mL/min/1.73 m² corresponds to actual GFR of 15 mL/min/1.73 m². 4