The effect of renal replacement therapy timing on the outcome of acute kidney injury in critically ill patients

Introduction The timing of renal replacement therapy (RRT) initiation in patients having acute kidney disease has been a controversial issue for many years. A recently published systematic review and meta-analysis on this topic failed to demonstrate measurable benefits of early RRT. Patients and methods We compared RRT initiation timing in critically ill patients and defined early or late RRT in reference to the timing after which stage 3 Acute Kidney Injury Network criteria were met. Patients beginning RRT within 24 h after reaching stage 3 acute kidney injury (AKI) were considered early starters, whereas those beginning RRT past 24 h after reaching stage 3 AKI were considered late starters. Acute Kidney Injury Network criteria were evaluated by both urine output and serum creatinine. Patients with acute-on-chronic kidney disease were excluded. A propensity score methodology was used to control variables. Results A total of 123 critically ill patients were subjected to RRT. Only 40 patients with pure stage 3 AKI were analyzed. Mortality was lower in the early RRT group than in the late RRT group (18.6 vs. 81.1%, P=0.000). Moreover, patients in the early RRT group had a lower duration of mechanical ventilation, RRT duration, vasopressor duration, and ICU discharge creatinine level. Conclusion Using a time-based approach could be a better means of assessing the association between RRT initiation and outcomes in patients with AKI. In patients with stage 3 AKI, RRT initiation within 24 h should be considered.