Classification and staging of acute kidney injury: beyond the RIFLE and AKIN criteria

Abstract

Acute kidney injury (AKI) is often overlooked in hospitalized patients, despite the fact that even mild forms are strongly associated with poor clinical outcomes such as increased mortality, morbidity, cardiovascular failure and infections. Research endorsed by the Acute Dialysis Quality Initiative led to the publication of a consensus definition for AKI--the RIFLE criteria (Risk, Injury, Failure, Loss of function, and End-stage renal disease)--which was designed to standardize and classify renal dysfunction. These criteria, along with revised versions developed by the AKI Network (AKIN), can detect AKI with high sensitivity and high specificity and describe different severity levels that aim to predict the prognosis of affected patients. The RIFLE and AKIN criteria are easy to use in a variety of clinical and research settings, but have several limitations: both utilize an increase in serum creatinine level from a hypothetical baseline value and a decrease in urine output, but these surrogate markers of renal impairment manifest relatively late after injury has occurred and do not consider the nature or site of the kidney injury. New biomarkers for AKI have shown promise for early diagnosis and prediction of the prognosis of AKI. As more data become available, they could, in the future, be incorporated into improved definitions or criteria for AKI.

Acute kidney injury classification: AKIN and RIFLE criteria in critical patients

“…The analysis of pooled data showed a stepwise increase in relative risk for death with increasing AKI severity (Risk, 2.40; Injury, 4.15; Failure, 6.37, with respect to non-AKI patients) [50] . Generally speaking, studies that have used the AKIN criteria rather than the RIFLE criteria did not seem to show any improvement in the sensitivity, robustness and predictive ability in the definition and classification of AKI [51] . The RIFLE and AKIN criteria can detect AKI with high sensitivity and high specificity and describe different severity levels that aim to predict the prognosis of affected patients.…”

“…New biomarkers such as neutrophil gelatinase-associated lipocalin, interleukin-18, kidney injury molecule-1 and cystatin C have shown promise for early diagnosis and prediction of the prognosis of AKI. As more data become available, they could be incorporated into improved definitions or criteria for AKI in the future [51][52][53] .…”

AKI after Transcatheter or Surgical Aortic Valve Replacement

“…2,3 Despite many attempts to identify effective interventions to prevent postoperative AKI, [4][5][6] the incidence of AKI after cardiac surgery is reported to remain as high as 30%. 7,8 Since the first successful surgical aortic valve replacement (SAVR) in 1960, 9 SAVR has remained the gold standard treatment for symptomatic severe aortic stenosis.…”

Evaluation of Acute Kidney Injury in Intensive Care Unit

“…The baseline serum creatinine level has been recommended for use as a marker to reflect the renal function. The baseline serum creatinine value has been estimated in various ways, such as the serum creatinine level on hospital admission, the minimum creatinine level during the hospital stay, the serum creatinine value estimated from the MDRD calculation (assuming estimated GFR=75ml/min/1,73m 2 ) or the lowest value among these (Ricci, 2011). The choice of estimation technique used to obtain the baseline creatinine value has a marked effect on the prevalence of AKI, severity of disease, and mortality risk associated with various stages of AKI.…”