Predictive Score for the Success of Discontinuation of Renal Replacement Therapy (RRT) in Intensive Care

Background and Rationale

Acute kidney injury (AKI) is a frequent and severe complication among patients admitted to intensive care units (ICUs), and it is associated with high morbidity, mortality, prolonged length of stay, and long-term renal impairment. In cases of severe AKI, renal replacement therapy (RRT), also referred to as extracorporeal renal replacement therapy (EER), remains the only effective supportive treatment capable of correcting life-threatening metabolic disturbances such as hyperkalemia, metabolic acidosis, fluid overload, and uremia.

Over the last decade, substantial progress has been made in defining optimal strategies for initiating RRT. Large randomized controlled trials, including AKIKI, IDEAL-ICU, and STARRT-AKI, have demonstrated that in the absence of immediate life-threatening complications, a conservative or "watchful waiting" strategy is safe and avoids unnecessary exposure to RRT in a significant proportion of patients. As a result, delayed initiation strategies have become standard of care in many ICUs.

In contrast, the question of when and how to discontinue RRT once renal function begins to recover remains insufficiently addressed. Current clinical practice regarding RRT discontinuation is highly heterogeneous and largely based on individual clinician judgment rather than objective, validated criteria. Prolonging RRT beyond what is necessary may expose patients to avoidable complications, including catheter-related infections, bleeding related to anticoagulation, hemodynamic instability, thrombosis, and nutritional losses, while also increasing healthcare costs and resource utilization.

International guidelines, including those from KDIGO, explicitly acknowledge the lack of evidence-based criteria for stopping RRT and highlight the need for reliable markers to predict successful weaning. Previous studies that attempted to identify predictors of successful RRT discontinuation were conducted before conservative initiation strategies became standard practice and often included patients who may not have had a validated indication for RRT. Moreover, these studies varied widely in terms of timing of assessment (during RRT, immediately after cessation, or days later), further limiting their applicability.