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: 2.5). 10/2010; 104(3):237-43. DOI: 10.1093/qjmed/hcq185
Source: PubMed


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.


Available from: Mar E Ostermann
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    • "It is clear from these studies that a consensus definition for renal failure is necessary for demonstrating its independent effect on mortality and morbidity, as has already been shown in cohorts of adults (RIFLE score, AKIN classification) and children (pediatric RIFLE) in intensive care units [18-20]. However, even in adult or pediatric cohorts, the lack of a consensus on a definition for acute renal failure has resulted in a limitation of each published score to predict outcome with a strong sensibility [31]. The increase in serum creatinine value is a marker of the severity of the illness in preterm newborns, strongly associated with mortality. "
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    ABSTRACT: Renal failure in neonates is associated with an increased risk of mortality and morbidity. But critical values are not known. To define critical values for serum creatinine levels by gestational age in preterm infants, as a predictive factor for mortality and morbidity. This was a retrospective study of all preterm infants born before 33 weeks of gestational age, hospitalized in Nantes University Hospital NICU between 2003 and 2009, with serum creatinine levels measured between postnatal days 3 to 30. Children were retrospectively randomized into either training or validation set. Critical creatinine values were defined within the training set as the 90(th) percentile values of highest serum creatinine (HSCr) in infants with optimal neurodevelopmental at two years of age. The relationship between these critical creatinine values and neonatal mortality, and non-optimal neural development at two years, was then assessed in the validation set. The analysis involved a total of 1,461 infants (gestational ages of 24-27 weeks (n=322), 28-29 weeks (n=336), and 30-32 weeks (803)), and 14,721 creatinine assessments. The critical values determined in the training set (n=485) were 1.6, 1.1 and 1.0 mg/dL for each gestational age group, respectively. In the validation set (n=976), a serum creatinine level above the critical value was significantly associated with neonatal mortality (Odds ratio: 8.55 (95% confidence interval: 4.23-17.28); p<0.01) after adjusting for known renal failure risk factors, and with non-optimal neurodevelopmental outcome at two years (odds ratio: 2.06 (95% confidence interval: 1.26-3.36); p=0.004) before adjustment. Creatinine values greater than 1.6, 1.1 and 1.0 mg/dL respectively at 24-27, 28-29, 30-32 weeks of gestation were associated with mortality before and after adjustment for risk factors, and with non-optimal neurodevelopmental outcome, before adjustment.
    PLoS ONE 12/2013; 8(12):e84892. DOI:10.1371/journal.pone.0084892 · 3.23 Impact Factor
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    ABSTRACT: Incluye bibliografía e índice
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    ABSTRACT: To compare urine output between junior doctors in an intensive care unit and the patients for whom they are responsible. Case-control study. General intensive care unit in a tertiary referral hospital. 18 junior doctors responsible for clerking patients on weekday day shifts in the unit from 23 March to 23 April 2009 volunteered as "cases." Controls were the patients in the unit clerked by those doctors. Exclusion criteria (for both groups) were pregnancy, baseline estimated glomerular filtration rate <15 ml/min/1.73 m(2), and renal replacement therapy. Oliguria (defined as mean urine output <0.5 ml/kg/hour over six or more hours of measurement) and urine output (in ml/kg/hour) as a continuous variable. Doctors were classed as oliguric and "at risk" of acute kidney injury on 19 (22%) of 87 shifts in which urine output was measured, and oliguric to the point of being "in injury" on one (1%) further shift. Data were available for 208 of 209 controls matched to cases in the data collection period; 13 of these were excluded because the control was receiving renal replacement therapy. Doctors were more likely to be oliguric than their patients (odds ratio 1.99, 95% confidence interval 1.08 to 3.68, P=0.03). For each additional 1 ml/kg/hour mean urine output, the odds ratio for being a case rather than a control was 0.27 (0.12 to 0.58, P=0.001). Mortality among doctors was astonishingly low, at 0% (0% to 18%). Managing our own fluid balance is more difficult than managing it in our patients. We should drink more water. Modifications to the criteria for acute kidney injury could be needed for the assessment of junior doctors in an intensive care unit.
    BMJ (online) 12/2010; 341(dec14 1):c6761. DOI:10.1136/bmj.c6761 · 17.45 Impact Factor
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