Timing of Kidney Replacement Therapy Initiation in Acute Kidney Injury

Alejandro Y. Meraz-Muñoz; Sean M. Bagshaw; Ron Wald


Curr Opin Nephrol Hypertens. 2021;30(3):332-338. 

In This Article

Abstract and Introduction


Purpose of Review: Over the past 5 years, four major randomized controlled trials were published informing our practice on the optimal timing for kidney replacement therapy (KRT) initiation in critically ill patients with acute kidney injury (AKI). In this review, we summarize the main findings of these trails and discuss the knowledge gaps that still need to be addressed.

Recent Findings: Four recent trials compared early versus delayed initiation of KRT in critically ill patients with acute kidney injury. Though each trial had unique design features, the three largest trials showed that earlier initiation of KRT did not reduce all-cause mortality.

Summary: A preemptive strategy for initiation of kidney replacement therapy does not confer better survival in critically ill patients with severe AKI. However, early initiation of KRT was associated with a greater risk of iatrogenic complications and one trial showed a higher risk of persistent dialysis dependence. In the absence of absolute indications for KRT, clinicians should defer KRT initiation in patients with AKI. Further research is needed to examine the safety of prolonged KRT deferral and identify markers of fluid overload that may serve to trigger KRT initiation.


Acute kidney injury (AKI) is a common complication of critical illness and is associated with important implications for morbidity, mortality and healthcare costs. AKI of some degree afflicts over 50% of critically ill patients with up to 15% receiving kidney replacement therapy (KRT).[1,2] Mortality of patients with severe AKI is high, exceeding 50% in those patients who require KRT. Moreover, survivors of AKI have a heightened risk of progressive CKD and cardiovascular events.[3–11]

Although KRT can be viewed as a life-saving technique for patients with severe AKI, it carries iatrogenic risks and entails greater resource utilization. In the United States, the adjusted cost increment of a hospitalization associated with the delivery of acute KRT is $11 000 USD compared with a hospitalization that is uncomplicated by AKI.[12] For these reasons, the deployment of KRT requires thoughtful consideration.