Definition Of Acute Renal Failure Research Articles

The Economic Consequences of Cardiac Surgery Associated Acute Renal Dysfunction After Heart Surgery

The Society of Thoracic Surgeons definition of acute renal failure requires a 3-fold rise in creatinine, creatinine > 4 mg/dL (with at least 0.5mg/dL rise from preoperative value), or new hemodialysis requirement. This definition does not capture the incidence, clinical impact, and economic burden of lesser degrees of acute renal dysfunction. A retrospective cohort study using discharge data from 650 hospitals was extracted from the Premier administrative database (2010-2014) for index cardiac cases (isolated coronary artery bypass grafting, isolated valve, and coronary artery bypass grafting-valve). We documented acute renal dysfunction through International Classification of Diseases (ICD) 9-CM codes and hospital charges, excluding those patients with pre-existing renal dysfunction. The incidence, length of stay , and total hospital costs associated with renal dysfunction for each of the index procedures were captured. The results reported are unadjusted for demographic and clinical factors. A total of 200,471 procedures were available for analysis in the database. The mean age was 66 years, 68.2% were male and 74% were white. Based on ICD 9-CM codes and hospital charges for these cases, 27,216 (13.6%) patients had some level of renal dysfunction. In addition to increase in length of stay, patients who developed renal dysfunction had an associated 57-85% increase in total cost of hospitalization. The incidence of renal dysfunction in this study is higher than reported previously. The Society of Thoracic Surgeons definition of renal failure captures only severe disease and may miss lesser degrees of dysfunction, which nonetheless have an impact on patient outcome and costs.

Association Between Intraoperative Oliguria and Acute Kidney Injury After Major Noncardiac Surgery.

Acute kidney injury (AKI) occurs in 6.1%-22.4% of patients undergoing major noncardiac surgery. Previous studies have shown no association between intraoperative urine output and postoperative acute renal failure. However, these studies used various definitions of acute renal failure. We therefore investigated the association between intraoperative oliguria and postoperative AKI defined by the serum creatinine criteria of the Risk, Injury, Failure, Loss, and End-stage kidney disease (RIFLE) classification. In this single-center, retrospective, observational study, we screened 26,984 patients undergoing elective or emergency surgery during the period September 1, 2008 to October 31, 2011 at a university hospital. Exclusion criteria were age <18 years; duration of anesthesia <120 minutes; hospital stay <2 nights; local anesthesia only; urologic or cardiac surgery; coexisting end-stage kidney disease; and absence of serum creatinine measurement, intraoperative urine output data, or information regarding intraoperative drug use. Multivariable logistic regression analysis was used as the primary analytic method. A total of 5894 patients were analyzed. The incidence of postoperative AKI was 7.3%. By multivariable analysis, ≥120 minutes of oliguria (odds ratio = 2.104, 95% CI, 1.593-2.778; P < .001) was independently associated with the development of postoperative AKI. After propensity-score matching of patients with ≥120 and <120 minutes of oliguria on baseline characteristics, the incidence of AKI in patients with ≥120 minutes of oliguria (n = 827; 10%) was significantly greater than that in those with <120 minutes of oliguria (n = 827; 4.8%; odds ratio = 2.195, 95% CI, 1.806-2.668; P < .001). Contrary to previous studies, we found that intraoperative oliguria is associated with the incidence of AKI after major noncardiac surgery.

Diagnosis and management of acute kidney injury in patients with cirrhosis: Revised consensus recommendations of the International Club of Ascites

Acute renal failure (ARF) is a common complication in patients with decompensated cirrhosis. The traditional diagnostic criteria of renal failure in these patients were proposed in 19961 and have been refined in subsequent years.2 According to these criteria, ARF is defined as an increase in serum creatinine (sCr) of ≥50% from baseline to a final value >1.5 mg/dL (133 µmol/L). However, the threshold value of 1.5 mg/dL (133 µmol/L) sCr to define renal failure in patients with decompensated cirrhosis has been challenged.3 ,4 In addition, the timeframe to distinguish acute from chronic renal failure has not been clearly identified, the only exception being type 1 hepatorenal syndrome (HRS). Meanwhile, new definitions for ARF, now termed acute kidney injury (AKI), have been proposed and validated in patients without cirrhosis.5–7 Recently these new criteria were also proposed and applied in the diagnosis of AKI in patients with cirrhosis.3 ,8–15 Thus, in December 2012, the International Club of Ascites (ICA) organised a consensus development meeting in Venice, Italy, in order to reach a new definition of AKI in patients with cirrhosis. The discussion among the experts continued thereafter for 2 years, both online and through several meetings, between those experts who had different positions on crucial points on the subject. This paper reports the scientific evidence supporting the final proposal of a new approach to the diagnosis and treatment of this condition, on which the experts agreed. AKI is defined as an acute significant reduction in the glomerular filtration rate (GFR). sCr remains the most practical biomarker of renal function in patients with ARF (with or without cirrhosis). However, sCr as a biomarker of renal function has many limitations in clinical practice since it is influenced by bodyweight, race, age, and gender. The use of sCr in patients with cirrhosis is …

Diagnosis and management of acute kidney injury in patients with cirrhosis: revised consensus recommendations of the International Club of Ascites

Acute renal failure (ARF) is a common complication in patients with decompensated cirrhosis. The traditional diagnostic criteria of renal failure in these patients were proposed in 19961 and have been...

Encuesta sobre el manejo del fracaso renal agudo y las técnicas de reemplazo renal en las unidades de cuidados intensivos españolas

AimTo analyze knowledge and experience in the diagnosis and management of acute renal failure (ARF) and the use of renal replacement therapy (RRT) in different Spanish Intensive Care Units (ICUs). DesignA case series with a survey conducted by the Nephro-Intensive Care Working Group of the SEMICYUC was compiled between January and November 2011. ScopeSpanish national ICUs. InterventionsA survey of 28 questions with multiple and open responses. ParticipantsThe survey was sent to 99 ICUs. Volunteers consisting of the medical staff belonging to the 51 ICUs that responded.Main variables of interest General characteristics of hospitals and ICUs, definitions of ARF and RRT (indications and management). ResultsRIFLE/AKIN scales to define ARF (47%). ARF diagnosis: plasma creatinine (80.4%), creatinine clearance (52.9%). Protocols for RRT: 72.5%. RRT in non-renal indications: 70.6%. Indications for initiation of RRT: oliguria, increased creatinine and urea. End of RRT: increased diuresis. RRT dose: 21-35ml/kg/h (41.2%), 36-45ml/kg/h (33.3%). ConclusionsThere is great variability in the ARF detection methods, and adequate incorporation of the RIFLE/AKIN systems to daily clinical practice in the ICU is still lacking. Written protocols aimed at establishing an early diagnosis of ARF are needed, based on these systems. On the other hand, there is growing interest in RRT, despite the fact that there are no definitive indications or guidelines on the use and handling of such techniques.

Prognostic value of acute kidney injury after cardiac surgery according to kidney disease: improving global outcomes definition and staging (KDIGO) criteria.

ObjectivesThe definition of acute renal failure has been recently reviewed, and the term acute kidney injury (AKI) was proposed to cover the entire spectrum of the syndrome, ranging from small changes in renal function markers to dialysis needs. This study was aimed to evaluate the incidence, morbidity and mortality associated with AKI (based on KDIGO criteria) in patients after cardiac surgery (coronary artery bypass grafting or cardiac valve surgery) and to determine the value of this feature as a predictor of hospital mortality (30 days).MethodsFrom January 2003 to June 2013, a total of 2,804 patients underwent cardiac surgery in our service. Cox proportional hazard models were used to determine the association between the development of AKI and 30-day mortality.ResultsA total of 1,175 (42%) patients met the diagnostic criteria for AKI based on KDIGO classification during the first 7 postoperative days: 978 (35%) patients met the diagnostic criteria for stage 1 while 100 (4%) patients met the diagnostic criteria for stage 2 and 97 (3%) patients met the diagnostic criteria for stage 3. A total of 63 (2%) patients required dialysis treatment. Overall, the 30-day mortality was 7.1% (2.2%) for patients without AKI and 8.2%, 31% and 55% for patients with AKI at stages 1, 2 and 3, respectively. The KDIGO stage 3 patients who did not require dialysis had a mortality rate of 41%, while the mortality of dialysis patients was 62%. The adjusted Cox regression analysis revealed that AKI based on KDIGO criteria (stages 1–3) was an independent predictor of 30-day mortality (P<0.001 for all. Hazard ratio = 3.35, 11.94 and 24.85).ConclusionIn the population evaluated in the present study, even slight changes in the renal function based on KDIGO criteria were considered as independent predictors of 30-day mortality after cardiac surgery.

Incidence and risk factors for acute kidney injury after spine surgery using the RIFLE classification

Earlier definitions of acute renal failure are not sensitive in identifying milder forms of acute kidney injury (AKI). The authors hypothesized that by applying the RIFLE criteria for acute renal failure (Risk of renal dysfunction, Injury to the kidney, Failure of kidney function, Loss of kidney function, and End-stage kidney disease) to thoracic and lumbar spine surgery, there would be a higher incidence of AKI. They also developed a model to predict the postoperative glomerular filtration rate (GFR). A hospital data repository was used to identify patients undergoing thoracic and/or lumbar spine surgery over a 5-year period (2006-2011). The lowest GFR in the first week after surgery was used to identify and categorize kidney injury if present. Risk factors were identified and a model was developed to predict postoperative GFR based on the defined risk factors. A total of 726 patients were identified over the study period. The incidence of AKI was 3.9% (n = 28) based on the RIFLE classification with 23 patients in the risk category and 5 in the injury category. No patient was classified into the failure category or required renal replacement therapy. The baseline GFR in the non-AKI and AKI groups was 80 and 79.8 ml/min, respectively. After univariate analysis, only hypertension was associated with postoperative AKI (p = 0.02). A model was developed to predict the postoperative GFR. This model accounted for 64.4% of the variation in the postoperative GFRs (r(2) = 0.644). The incidence of AKI in spine surgery is higher than previously reported, with all of the patients classified into either the risk or injury RIFLE categories. Because these categories have previously been shown to be associated with poor long-term outcomes, early recognition, management, and follow-up of these patients is important.

Insuffisance et agression rénales aiguës périopératoires

Perioperative period is very likely to lead to acute renal failure because of anesthesia (general or perimedullary) and/or surgery which can cause acute kidney injury. Characterization of acute renal failure is based on serum creatinine level which is imprecise during and following surgery. Studies are based on various definitions of acute renal failure with different thresholds which skewed their comparisons. The RIFLE classification (risk, injury, failure, loss, end stage kidney disease) allows clinicians to distinguish in a similar manner between different stages of acute kidney injury rather than using a unique definition of acute renal failure. Acute renal failure during the perioperative period can mainly be explained by iatrogenic, hemodynamic or surgical causes and can result in an increased morbi-mortality. Prevention of this complication requires hemodynamic optimization (venous return, cardiac output, vascular resistance), discontinuation of nephrotoxic drugs but also knowledge of the different steps of the surgery to avoid further degradation of renal perfusion. Diuretics do not prevent acute renal failure and may even push it forward especially during the perioperative period when venous retourn is already reduced. Edema or weight gain following surgery are not correlated with the vascular compartment volume, much less with renal perfusion. Treatment of perioperative acute renal failure is similar to other acute renal failure. Renal replacement therapy must be mastered to prevent any additional risk of hemodynamic instability or hydro-electrolytic imbalance.

Das akute Nierenversagen - Nierenersatzverfahren auf der Intensivstation

Depending on the individual definition of acute renal failure, its prevalence in intensive care units approaches 5-25 % of the cases under treatment and is associated with a definitely reduced survival rate. Hence, prevention of acute renal failure should always rank first. However, if renal replacement is nevertheless inevitable, we must definitely decide between a permanent and an intermittent procedure on the one hand and between hemodialysis and hemofiltration on the other. „Sustained low efficiency dialysis“ (SLED) during 8-12 hours is a good alternative combining the advantages of hemodialysis and continuous treatment. Hemodynamically unstable as well as definitely hyper-hydrated patients or patients suffering from hepatic insufficiency or increased intracranial pressure (e. g. skull and brain trauma) will improve in case of acute electrolytic disorders such as hyperkalemias, intoxications, hemorrhagic diathesis or in the mobilization phase. Intensive care specialists and nephrologists should individually decide which procedure would be preferable. The present article aims at assisting them.

Zero Mortality of Continuous Veno-venous Hemodiafiltration with PMMA Hemofilter after Pediatric Cardiac Surgery

Continuous veno-venous hemodiafiltration (CVVH) is used as one of the modalities of continuous renal replacement therapy (CRRT) in pediatric intensive units. The aim of our study was to investigate the use of CVVH in small children with acute renal failure (ARF) after cardiac surgery. Between June 2005 and June 2008, 7 patients who required dialysis after pediatric cardiac surgery without ECMO underwent CVVH with polymethylmethacrylate membrane (PMMA) treatment. The definition of ARF was based on a 100% rise in serum creatinine (Cr) concentration, oliguria. On the other hand, PMMA-CVVH was weaned in patients with satisfactory urine output, stable biochemical markers of renal function and adequate fluid balance. All patients treated with PMMA-CVVH alone (4 boys, 3 girls) had a median age of 36 months and a median body weight of 11 kg. The averaged established time from cardiac operation to CVVH was 2.6 days. There was a significant decrease in the post-filter compared with pre-filter levels of BUN, Cr, potassium concentration. There were no significant changes in systolic blood pressure, lactate level and CRP; however, it was unnecessary for all patients to use epinephrine. Continuous veno-venous hemodiafiltration with PMMA-CVVH without ECMO achieved a surprisingly Zero mortality.

Modifications péri-opératoires de la fonction rénale

Impaired microcirculation and tubule injuries explain the changes in kidney function during and after surgery. Surgery is a risk factor for acute renal failure, the incidence of which ranges from 0.8% to 40%, depending on the kind of surgery. Mortality due to perioperative acute renal failure ranges from 17% to 60%, depending on the kind of surgery. For almost 10 to 20% of survivors, acute renal failure becomes chronic. Of the various definitions of acute renal failure, the RIFLE classification(risk of renal dysfunction, injury to the kidney, failure of kidney function, loss of kidney function, end-stage kidney disease)is a consensus definition for predicting hospital mortality. Preoperative renal function was based on serum creatinine and creatinine clearance, calculated with either the Cockcroft and Gault or modification of diet in renal disease (MDRD) formula. Predictors of postoperative acute renal failure include: previous renal dysfunction (most predictive), age older than 56 years, peripheral vascular occlusive disease, chronic obstructive pulmonary disease, congestive heart failure, hypertension and diabetes mellitus, body mass index over 32, use of a vasopressor infusion and diuretic administration, emergency or major surgery, and liver disease. Biomarkers for acute kidney injury are useful for diagnosis of early renal dysfunction. The most promising of these isneutrophil gelatinase-associated lipocalin(NGAL). Renal protection consists in maintaining an optimal blood volume and cardiac output. Nephrotoxic agents always must be removed.

Acute renal failure in cardiothoracic surgery patients: what is the best definition of this common and potent predictor of increased morbidity and mortality

Background Universal agreement on criteria for acute renal failure (ARF) is lacking. The purpose of the current study was to determine which of 6 definitions for ARF best predicted clinical outcomes in postoperative cardiothoracic surgery (CTS) patients. Methods Criteria for ARF were retrospectively applied to 1,085 CTS patients. General linear models analyzed length of stay (LOS) and ventilator days with logistic regression for mortality. Results Thirty-seven percent of patients met at least 1 of 6 definitions of ARF. For each 1-mg/dL increase from the initial creatinine, LOS increased by 6.96 days, ventilator days increased by 3.58 days, and mortality increased by 2.23 times ( P < .0001). Conclusions One definition that best predicted ARF was not found. ARF was a significant independent predictor of increased mortality, LOS, and ventilator days. Even small increases in creatinine correlate with clinically significant worsening of expected outcomes.

Letter by Bouchard et al Regarding Article “Aprotinin Does Not Increase the Risk of Renal Failure in Cardiac Surgery Patients”

To the Editor: Two recent publications have given rise to concerns regarding the safety of intraoperative aprotinin on renal function after cardiac surgery.1,2 Contrary to these studies, Furnary et al3 demonstrated that aprotinin does not increase the risk of acute renal failure (ARF) independently of the number of transfusions administered. We have 3 concerns regarding the findings of these studies that impair an adequate comparison of their results. First, all 3 studies used different definitions for ARF. Furnary et al3 selected the new requirement of dialysis as the ARF outcome, presumably because the risk predictive score has been validated for ARF requiring dialysis …

Acute kidney injury

Diagnosis and classification of acute pathology in the kidney are major clinical problems. Azotemia and oliguria represent not only disease but normal responses of the kidney to extracellular volume depletion or decreased renal blood flow. Changes in urine output and glomerular filtration rate are therefore neither necessary nor sufficient for the diagnosis of renal pathology. However, no simple alternative for the diagnosis currently exists. By examining both glomerular and tubular function, clinicians routinely make inferences not only on the presence of renal dysfunction but also on its cause. However, pure prerenal physiology is unusual in hospitalized patients, and its effects are not necessary benign. Sepsis, the most common condition associated with acute renal failure in the intensive care unit, may alter renal function without any characteristic changes in urine indices, and classification of these abnormalities as prerenal will undoubtedly lead to incorrect management decisions. The clinical syndrome known as acute tubular necrosis does not actually manifest the morphologic changes that the name implies. A precise biochemical definition of acute renal failure has never been proposed, and until recently, there has been no consensus on the diagnostic criteria or clinical definition. Depending on the definition used, acute renal failure has been reported to affect from 1% to 25% of intensive care unit patients and has led to mortality rates ranging from 15% to 60%. From this chaos, two principles emerged: first, the need for a standard definition and, second, the need to classify the severity of the syndrome rather than only consider its most severe form. The RIFLE criteria were developed to achieve these goals, and the term acute kidney injury has been proposed to encompass the entire spectrum of the syndrome, from minor changes in renal function to requirement for renal replacement therapy. Thus, acute kidney injury is not acute tubular necrosis, nor is it renal failure. Small changes in kidney function in hospitalized patients are important and are associated with significant changes in short-term and possibly long-term outcomes. The RIFLE criteria provide a uniform definition of acute kidney injury and have now been validated in numerous studies.

Impact of minimal increases in serum creatinine on outcome in patients after cardiothoracic surgery: Do we have to revise current definitions of acute renal failure?*

Traditional cutoff values of serum creatinine considered to define postoperative acute renal failure have been challenged recently. In a previous investigation we demonstrated that minimal changes in serum creatinine concentration were associated with a substantial decrease in survival after cardiac surgery. In this investigation, we assessed the impact of minimal absolute increases in serum creatinine in a second institution, and we analyzed whether relative changes, as in the RIFLE classification and, partially, in Acute Kidney Injury Network (AKIN) classification, confer a different prognostic potential. Prospective analysis. University hospital. All consecutive patients undergoing cardiac surgery in the University Hospital of Zurich (Center USZ) over a 46-month period. Patients were prospectively documented. We analyzed maximal changes in serum creatinine in the first 48 hrs postoperatively (DeltaCrea) regarding death within 30 days. Results were compared with those of the University Hospital Vienna (Center AKH). Moreover, the prognostic potential of DeltaCrea within 48 hrs vs. serum creatinine elements according to RIFLE and AKIN classifications was assessed. A total of 3,123 patients were evaluated from USZ. The majority of patients had decreased postoperative serum creatinine values (negative DeltaCrea) and the lowest mortality (1.8%). Minimal increases, [0, 0.5) mg x dL(-1), were associated with a more than doubled mortality in both centers (5%/6%). Mortality, according to RIFLE and AKIN classifications for both populations combined, was as follows: 7,023 (3.6%), 160 (29%), 43 (19%), and 15 (33%) for RIFLE Normal, Risk, Injury, and Failure; 6,644 (2.8), 463 (16.4), 3 (66.7), and 131 (1.8) for AKIN stage 0, 1, 2, and 3. Measuring repeat serum creatinine concentrations within 48 hrs and determining DeltaCrea were the most effective discrimination method to find patients at risk for adverse postoperative outcome after cardiac surgery, better than application of this sole criterion to the RIFLE (least discriminatory) or the AKIN classification.

Defining and classifying AKI: one set of criteria

Over the last several years there have been consistent calls for a consensus definition and classification system for the syndrome now known as acute kidney injury (AKI) [1,2]. The major aim of such a system, it was argued, would be to bring this major intensive care syndrome to a standard of definition and a level of classification similar to that achieved by other common ICU syndromes (e.g. sepsis and acute lung injury). Following such advocacy and through the persistent work of the Acute Dialysis Quality Initiative (ADQI) group, such a system was developed through a broad consensus of experts [3]. The classification system that resulted is the RIFLE criteria, an acronym for three levels of severity: risk, injury and failure, and two outcomes: persistent acute renal failure termed loss and end-stage kidney disease. RIFLE was initially greeted with skepticism by both the critical care and nephrology communities. Concern was raised over the use of very small alterations in the serum creatinine and urine output and some objected to the use of an acronym instead of the numerical stages used in chronic kidney disease. Interestingly, others were concerned that a 50% increase in serum creatinine was too conservative and sought to demonstrate that even smaller changes were important [4]. However, the original publication of the RIFLE criteria has now been accessed more than 100 000 times [5] and RIFLE has become the most widely used definition of acute renal failure in both the critical care and nephrology literature [6–10]. The total number of patients included in studies validating RIFLE now exceeds 200 000. Thus, the goal of standardizing a definition and classification system for one of the most common ICU syndromes would appear to have been realized. However, standards do

Acute kidney injury: Epidemiology and assessment

An evolving understanding of epidemiology and pathophysiology of acute organ dysfunction in the setting of critical illness has given rise to new concepts and terminology for a syndrome once known as either acute tubular necrosis or acute renal failure. Indeed, the clinical syndrome known as acute tubular necrosis does not actually manifest the morphological changes that the name implies. Similarly, a precise biochemical definition of acute renal failure was never proposed, and until recently there has been no consensus on the diagnostic criteria or clinical definition. The RIFLE criteria were developed to achieve diagnostic standardization and the term acute kidney injury (AKI) has been proposed to encompass the entire spectrum of the syndrome from minor changes in renal function to requirement for renal replacement therapy. AKI is not acute tubular necrosis nor is it acute renal failure. Small changes in kidney function in hospitalized patients are important and are associated with significant changes in short and possibly long‐term outcomes. The RIFLE criteria provide a uniform definition of AKI and have now been validated in numerous studies. The population incidence of AKI is approximately 2000–3000 patients per million population per year. The incidence of AKI is increasing and ICU patients with AKI have a longer length of stay and therefore generate greater costs. In addition, AKI is associated with increased mortality, even after correction for covariates. Patients with AKI who are treated with RRT, still have a mortality of 50–60 %. Of surviving patients, 5–20 % remain dialysis‐dependent at hospital discharge.

Defining Acute Renal Failure: The RIFLE Criteria

Acute renal failure is common among critically ill patients and carries significant morbidity and mortality. The reported incidence and the attributed morbidity and mortality of acute renal failure vary widely, largely owing to the use of a wide variety of definitions for acute renal failure. Until recently, no consensus existed about how to best define, characterize, and study acute renal failure. This lack of a standard definition has been a major impediment to the progress of clinical and basic research in this field. This review outlines some of the physiologic principles that may help us better understand and define acute renal failure and describes the RIFLE criteria (an acronym comprising Risk, Injury, and Failure; and Loss, and End-stage kidney disease), a recent consensus method of defining and stratifying acute renal failure. Also discussed are many of the challenges and controversies associated with achieving consensus and developing a classification for acute renal dysfunction.

Defining and classifying acute renal failure: from advocacy to consensus and validation of the RIFLE criteria

Until recently, more than 30 different definitions of acute renal failure (ARF) had been used in the literature. This lack of a common reference point created confusion and made comparisons difficult. It also led to strong advocacy of a consensus definition. In response to the need for a common definition and classification of ARF, the Acute Dialysis Quality Initiative (ADQI) group of experts developed and published a consensus definition of ARF. This definition goes under the acronym of RIFLE to indicate that it classifies patients with renal dysfunction according to the degree of impairment into patients at risk (R), with injury (I), with failure (F), with sustained loss (L) and with end-stage (E) status in relation to their renal function. This editorial aims to summarize and interpret recent findings concerning the application of the RIFLE criteria to the assessment of the epidemiology and the prediction of the outcome of ARF.

Comparison of 2 Acute Renal Failure Severity Scores to General Scoring Systems in the Critically Ill

Several proposed definitions for acute renal failure (ARF) exist, but little is known of their significance in clinical practice. We evaluated the ability to predict hospital mortality in 2 ARF-specific severity-of-illness scoring methods, the Risk, Injury, Failure, Loss, End-Stage Renal Disease (RIFLE) score and the score presented by Bellomo et al in 2001. The study included 668 consecutive patients with 694 treatment episodes treated in 2 intensive care units (ICUs) in a university hospital within 11 months. ARF prevalence was classified according to the RIFLE and Bellomo scores. As references, we evaluated 2 general severity-of-illness scoring systems, the admission Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores. Admission SOFA scores and maximum RIFLE scores for the first 3 days in the ICU were independent predictors of hospital mortality by means of forward conditional logistic regression. In receiver operating characteristic analysis, SOFA and APACHE II scores performed better than ARF-specific scores, and discriminative powers for hospital mortality were only moderate for the RIFLE and Bellomo scores: areas under the curve were 0.653 (95% confidence interval, 0.588 to 0.719) and 0.587 (95% confidence interval, 0.514 to 0.660), respectively. Neither of the ARF-specific scoring methods presented good discriminative power regarding hospital mortality. However, maximum RIFLE score for the first 3 days in the ICU was found to be an independent predictor of hospital mortality, along with admission SOFA score.