When to start dialysis in patients with acute kidney injury? When semantics and logic become entangled with expectations and beliefs.

Earlier initiation of dialysis may have a beneficial impact on survival of critically ill patients with acute kidney injury (AKI). A retrospective analysis in the previous issue of Critical Care showed that early initiation of renal replacement therapy (RRT), as defined by RIFLE criteria, was not associated with a reduction in hospital mortality. The retrospective character of many studies describing the results of early RRT initiation and the validity of RIFLE criteria to determine the need for dialysis can be questioned, in particular when urinary output is not considered. Initiating dialysis in AKI should be based on clinical criteria and not on serum creatinine or another serum/urine-based biomarker.