What are the indications for initiating hemodialysis (HD) in patients with impaired renal function?

Indications for Initiating Hemodialysis

Hemodialysis should be initiated when GFR falls below 10 mL/min/1.73 m² in the presence of uremic symptoms, severe metabolic derangements, or progressive malnutrition—not based solely on GFR threshold, as early initiation (GFR >10 mL/min/1.73 m²) 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 target GFR for initiation is approximately 10 mL/min/1.73 m², which corresponds to a weekly Kt/V of 2.0, approximating a kidney urea clearance of 7 mL/min and creatinine clearance of 9-14 mL/min/1.73 m². 2

• Mean GFR at dialysis initiation is 9.8 mL/min/1.73 m², with lower values (7-9 mL/min/1.73 m²) for young and middle-aged adults and higher values (10-10.5 mL/min/1.73 m²) for children and elderly patients. 2

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

Absolute Clinical Indications (Override GFR Threshold)

Initiate dialysis immediately when any of the following are present, regardless of GFR level:

Uremic Symptoms

• Pericarditis (uremic pericardial friction rub or effusion) 1
• Uremic encephalopathy (altered mental status, asterixis, seizures) 1
• Intractable nausea and vomiting unresponsive to antiemetics 1
• Uremic bleeding diathesis (platelet dysfunction causing bleeding) 1

Volume and Hemodynamic Complications

• Volume overload refractory to maximal diuretic therapy (loop diuretics at maximum doses) 1
• Uncontrolled hypertension despite maximal medical management with 3+ antihypertensive agents 1

Metabolic Derangements

• Severe metabolic acidosis (pH <7.20 or bicarbonate <10 mEq/L) unresponsive to oral alkali therapy 1
• Hyperkalemia (K+ >6.5 mEq/L or any level with ECG changes) unresponsive to medical therapy 1

Nutritional Deterioration

• Protein-energy malnutrition that develops or persists despite vigorous attempts to optimize protein-energy intake, with no apparent cause other than low nutrient intake. 2, 1
• Progressive decline in edema-free body weight 2
• Serum albumin falling below laboratory lower limit and continuing to decline 2
• Lean body mass <63% 2

Conditions Allowing Safe Deferral (Even with GFR <10 mL/min/1.73 m²)

Dialysis may be safely deferred when ALL of the following criteria are met:

• Stable or increased edema-free body weight 2
• Adequate nutritional parameters (serum albumin above laboratory lower limit and stable/rising, lean body mass ≥63%, adequate subjective global assessment score) 2
• Complete absence of clinical signs or symptoms attributable to uremia 2

Critical Caveats and Pitfalls

GFR Estimation Limitations

• In patients with unusual creatinine generation (severe malnutrition, amputation, neuromuscular disease, extreme body habitus) or altered tubular secretion (trimethoprim, cimetidine, advanced liver disease), use measured GFR via 24-hour urine collection for creatinine and urea clearances rather than estimated GFR. 2

• The MDRD equation overestimates true GFR at low levels—when measured inulin clearance is 15 mL/min/1.73 m², MDRD will read approximately 19.7 mL/min/1.73 m². 4

Risks of Dialysis Itself

• Hemodialysis is not innocuous and does not replace all kidney functions; HD-related hypotension may accelerate loss of residual kidney function. 2, 1

• Vascular access complications increase with dialysis initiation 2, 1

• Dialysis imposes significant burden on patient, family, and healthcare system 2

Patient-Specific Factors Influencing Timing

• Patients with heart failure, serum albumin <4.0 g/dL, BUN/Cr ratio >15, or hyperuricemia are more likely to require dialysis at higher GFR levels and should have earlier vascular access creation and counseling. 5

• Planned elective dialysis initiation (with permanent access created when GFR ~5 mL/min/1.73 m²) reduces mortality and hospitalization compared to urgent/unplanned starts. 6

• In peritoneal dialysis patients, initiation at measured GFR ≤5 mL/min/1.73 m² is associated with significantly worse patient and technique survival compared to initiation at GFR >10 mL/min/1.73 m². 7

Initial Dialysis Prescription

When dialysis is initiated, the first treatment must use a "low and slow" approach to prevent dialysis disequilibrium syndrome:

• Initial session duration: 2-2.5 hours (not full 3-4 hours) 8
• Reduced blood flow rates: 200-250 mL/min 8
• Minimal ultrafiltration during first session, focusing on clearance rather than fluid removal 8
• Gradual dose escalation over subsequent sessions as tolerated 8
• Frequent vital sign monitoring (every 15-30 minutes) during first session 8

Peritoneal Dialysis-Specific Indications for Switching to Hemodialysis

• Inadequate solute transport despite maximum PD prescription (increased volumes, frequency of exchanges, nocturnal cycling) 2
• Inadequate ultrafiltration due to high transport characteristics or mechanical catheter defects 2
• Unacceptably frequent peritonitis (individually determined based on patient factors and HD facility availability) 2
• Unmanageably severe hypertriglyceridemia exacerbated by dextrose dialysate load 2
• Irreparable technical/mechanical defects (catheter malposition causing access failure) 2
• Severe malnutrition resistant to aggressive management on PD 2