Early Renal Replacement Therapy Does Not Improve Renal Outcomes in Acute Kidney Injury
Early initiation of renal replacement therapy (RRT) is not recommended for patients with acute kidney injury (AKI) as it does not improve renal outcomes and may increase complications. 1
Evidence on Timing of RRT Initiation
The timing of RRT initiation in patients with AKI has been extensively studied with consistent findings:
- The 2017 Surviving Sepsis Campaign guidelines explicitly recommend against early RRT initiation in patients with sepsis and AKI when there are no definitive indications for dialysis 1
- Two large RCTs published in 2016 showed conflicting results regarding mortality benefits, but demonstrated potential harms including increased catheter-related bloodstream infections with early RRT 1, 2
- A 2020 individual patient data meta-analysis of 9 studies with 1,879 patients found no significant difference in 28-day mortality between early and delayed RRT groups (RR 1.01,95% CI 0.91-1.13) 3
- A 2021 meta-analysis with trial sequential analysis of 11 studies involving 5,086 patients confirmed no mortality benefit with early RRT initiation 4
- A 2022 Cochrane review of 12 studies with 4,880 participants found that early RRT initiation had no beneficial effect on mortality (RR 0.97,95% CI 0.87-1.09) 5
Harms of Early RRT Initiation
Early RRT initiation is associated with several adverse events:
- Higher incidence of catheter-related bloodstream infections (10% vs. 5%, p=0.03) 2
- Increased risk of hypophosphataemia (RR 1.80), hypotension (RR 1.54), cardiac-rhythm disorders (RR 1.35), and infections (RR 1.33) 5
- Unnecessary RRT exposure in patients who might have recovered kidney function without intervention 4, 3
Benefits of Delayed RRT Strategy
A delayed or standard approach to RRT initiation offers several advantages:
- Avoids unnecessary RRT in a significant proportion of patients (approximately 42-49% of patients in the delayed groups never required RRT) 2, 3
- Earlier diuresis, suggesting faster recovery of kidney function 2
- Conservation of healthcare resources 3
When to Initiate RRT
RRT should be initiated when one or more of these indications are present:
- Severe hyperkalemia
- Metabolic acidosis
- Pulmonary edema
- Blood urea nitrogen level >112 mg/dL
- Oliguria for >72 hours
- Uremic complications (encephalopathy, pericarditis)
Considerations for Different RRT Modalities
When RRT is indicated, the choice of modality should consider:
- Continuous RRT (CRRT) is preferred for hemodynamically unstable patients as it provides better fluid balance management 6
- Intermittent hemodialysis is an alternative if CRRT is unavailable 6
- A typical dose for CRRT would be 20-25 mL/kg/hr of effluent generation 1
Monitoring for RRT Discontinuation
When considering discontinuation of RRT:
- Urine output prior to discontinuation is the most robust predictor of successful RRT discontinuation (sensitivity 66.2%, specificity 73.6%) 1
- Monitor for recovery of intrinsic kidney function that is adequate to meet patient needs 1
Conclusion
The current evidence strongly suggests that early initiation of RRT in patients with AKI does not improve renal outcomes and may lead to unnecessary treatments and complications. A delayed approach with close monitoring for traditional indications for RRT is the preferred strategy.