Challenges of defining acute kidney injury.

Department of Critical Care, Guy's & St Thomas' Foundation Hospital, London SE1 7EH, UK.
QJM: monthly journal of the Association of Physicians (Impact Factor: 2.46). 10/2010; 104(3):237-43. DOI: 10.1093/qjmed/hcq185
Source: PubMed

ABSTRACT Until recently, there was a lack of a uniform definition for acute kidney injury (AKI). The 'acute renal injury/acute renal failure syndrome/severe acute renal failure syndrome' criteria, the Risk - Injury - Failure - Loss of kidney function - End stage renal disease (RIFLE) criteria and the Acute Kidney Injury Network (AKIN) classification were the most recent proposals.
To compare the performance of the different AKI definitions. Design and
Application of the three most recent AKI definitions to 41 972 critically ill ICU patients and comparison of their performance.
Incidence and outcome of AKI varied depending on the criteria. The RIFLE and AKIN classification led to similar total incidences of AKI (35.9 vs. 35.4%) but different incidences and outcomes of the individual AKI stages. Multivariate analysis showed that the different stages of AKI were independently associated with mortality. The worst stage of AKI was associated with an increased odds ratio for mortality of 1.59-2.27. Non-surgical admission, maximum number of associated failed organ systems, emergency surgery and mechanical ventilation were consistently associated with the highest risk of hospital mortality. The proposed AKI definitions differ in the cut-off values of serum creatinine, the suggested time frame, the approach towards patients with missing baseline values and the method of classifying patients on renal replacement therapy. All classifications can miss patients with definite AKI.
The three most recent definitions of AKI confirmed a correlation between severity of AKI and outcome but have limitations and the potential to miss patients with definite AKI. These limitations need to be considered when using the criteria in clinical practice.

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    ABSTRACT: Acute kidney injury (AKI) in patients hospitalized for acute heart failure (AHF) is usually type 1 of the cardiorenal syndrome (CRS) and has been associated with increased morbidity and mortality. Early recognition of AKI is critical. This study was to determine if the new KDIGO criteria (Kidney Disease: Improving Global Outcomes) for identification and short-term prognosis of early CRS type 1 was superior to the previous RIFLE and AKIN criteria. The association between AKI diagnosed by KDIGO but not by RIFLE or AKIN and in-hospital mortality was retrospectively evaluated in 1005 Chinese adult patients with AHF between July 2008 and May 2012. AKI was defined as RIFLE, AKIN and KDIGO criteria, respectively. Cox regression was used for multivariate analysis of in-hospital mortality. Within 7 days on admission, the incidence of CRS type 1 was 38.9% by KDIGO criteria, 34.7% by AKIN, and 32.1% by RIFLE. A total of 110 (10.9%) cases were additional diagnosed by KDIGO criteria but not by RIFLE or AKIN. 89.1% of them were in Stage 1 (AKIN) or Stage Risk (RIFLE). They accounted for 18.4% (25 cases) of the overall death. After adjustment, this proportion remained an independent risk factor for in-hospital mortality [odds ratios (OR)3.24, 95% confidence interval(95%CI) 1.97-5.35]. Kaplan-Meier curve showed AKI patients by RIFLE, AKIN, KDIGO and [K(+)R(-)+K(+)A(-)] had lower hospital survival than non-AKI patients (Log Rank P<0.001). KDIGO criteria identified significantly more CRS type 1 episodes than RIFLE or AKIN. AKI missed diagnosed by RIFLE or AKIN criteria was an independent risk factor for in-hospital mortality, indicating the new KDIGO criteria was superior to RIFLE and AKIN in predicting short-term outcomes in early CRS type 1.
    PLoS ONE 12/2014; 9(12):e114369. · 3.53 Impact Factor
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    ABSTRACT: Acute kidney injury (AKI) is a common syndrome that is independently associated with increased mortality. A standardized definition is important to facilitate clinical care and research. The definition of AKI has evolved rapidly since 2004, with the introduction of the Risk, Injury, Failure, Loss, and End-stage renal disease (RIFLE), AKI Network (AKIN), and Kidney Disease Improving Global Outcomes (KDIGO) classifications. RIFLE was modified for pediatric use (pRIFLE). They were developed using both evidence and consensus. Small rises in serum creatinine are independently associated with increased mortality, and hence are incorporated into the current definition of AKI. The recent definition from the international KDIGO guideline merged RIFLE and AKIN. Systematic review has found that these definitions do not differ significantly in their performance. Health-care staff caring for children or adults should use standard criteria for AKI, such as the pRIFLE or KDIGO definitions, respectively.These efforts to standardize AKI definition are a substantial advance, although areas of uncertainty remain. The new definitions have enabled the use of electronic alerts to warn clinicians of possible AKI. Novel biomarkers may further refine the definition of AKI, but their use will need to produce tangible improvements in outcomes and cost effectiveness. Further developments in AKI definitions should be informed by research into their practical application across health-care providers. This review will discuss the definition of AKI and its use in practice for clinicians and laboratory scientists.Kidney International advance online publication, 15 October 2014; doi:10.1038/ki.2014.328.
    Kidney International 10/2014; · 8.52 Impact Factor
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    ABSTRACT: Acute kidney injury (AKI) is common. Clear criteria and accurate diagnostic tools are essential to diagnose AKI early and correctly. The aims of this review are to outline some of the pitfalls of the Kidney Disease Improving Global Outcomes (KDIGO) classification and to describe other traditional and novel tools to diagnose AKI.
    Current opinion in critical care. 10/2014;

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