Recommendation ID
Definition of acute kidney injury – system for staging and detection:- Can a simplified definition and staging system, based on Système International (SI) units, be used to predict short- to medium-term outcomes in acute kidney injury?
Any explanatory notes
(if applicable)
Why this is important:- Definitions of acute kidney injury have evolved fairly rapidly in recent years, from RIFLE (2004), through AKIN (2007), to KDIGO (2012) (a merger of RIFLE and AKIN, but with less rigorous requirements for detection in those with chronic kidney disease). All three are complex and rely on non-SI units for creatinine.
Absolute creatinine rises have been shown to be independently associated with mortality, but the evidence comes from US studies that used non-SI units for creatinine. Stage 1 acute kidney injury is currently defined by a rise in creatinine of 0.3 mg/dl within 48 hours, which translates to 26.4 micromol/litre in SI units (note that laboratories report creatinine as an integer value only). The current definitions are complex and difficult to use for non-specialists in healthcare systems that use SI units for creatinine measurement (including the UK). A large, prospective epidemiological or cohort study is needed to investigate whether a simplified system, derived from KDIGO, would be useful for detecting and staging acute kidney injury in the NHS. The study should investigate the relationship of acute kidney injury, as defined by creatinine rise in SI units, with outcomes, adjusted for comorbidity. It also needs to investigate whether the same absolute rise in creatinine equally reflects outcomes among patients with and without chronic kidney disease. The study should include a control group (for example, patients admitted to hospital as an emergency with an acute illness, but without acute kidney injury) and be adequately powered to show the effect of acute kidney injury on mortality, length of stay and dialysis for acute kidney injury at 6 months.

Source guidance details

Comes from guidance
Acute kidney injury: prevention, detection and management
Date issued
August 2013

Other details

Is this a recommendation for the use of a technology only in the context of research? No  
Is it a recommendation that suggests collection of data or the establishment of a register?   No  
Last Reviewed 04/09/2013