Interpreting trials on renal replacement therapy initiation: beware of methodologic issues

Excerpt

No large-scale randomized controlled trial (RCT) on the initiation strategy for renal replacement therapy (RRT) in critically ill patients with acute kidney injury (AKI) was available for years. Expert opinion [1] and consensus conferences [2] recommend a conservative approach with RRT initiated only when life-threatening complications (hyperkalemia, intractable acidosis, or diuretic-unresponsive pulmonary edema) are present. However, RRT is often initiated earlier based mainly on amount of hourly urine output and/or urea nitrogen or serum creatinine concentration [3] even in the absence of the abovementioned complications. This attitude is based on the putative deleterious effects of high levels of nitrogen waste products and of hypothetical ill-effects of mediators of inflammation or other elusive factors. This approach assumes that theoretical advantages of early RRT surpass its actual risks, including catheter-related problems, hypotension, complications of anticoagulation, and the risk that treatment may actually prolong the course of AKI. …