BACKGROUND: Although the present diagnosis of acute kidney injury (AKI) involves measurement of acute increases in serum creatinine (SC) and reduced urine output (UO), measurement of UO is underutilized for diagnosis of AKI in clinical practice. The purpose of this investigation was to conduct a systematic literature review of published studies that evaluate both UO and SC in the detection of AKI to better understand incidence, healthcare resource use, and mortality in relation to these diagnostic measures and how these outcomes may vary by population subtype.
METHODS: The systematic literature review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. Data were extracted from comparative studies focused on the diagnostic accuracy of UO and SC, relevant clinical outcomes, and resource usage. Quality and validity were assessed using the National Institute for Health and Care Excellence (NICE) single technology appraisal quality checklist for randomized controlled trials and the Newcastle-Ottawa Quality Assessment Scale for observational studies.
RESULTS: A total of 1729 publications were screened, with 50 studies eligible for inclusion. A majority of studies (76%) used the Kidney Disease: Improving Global Outcomes (KDIGO) criteria to classify AKI and focused on the comparison of UO alone versus SC alone, while few studies analyzed a diagnosis of AKI based on the presence of both UO and SC, or the presence of at least one of UO or SC indicators. Of the included studies, 33% analyzed patients treated for cardiovascular diseases and 30% analyzed patients treated in a general intensive care unit. The use of UO criteria was more often associated with increased incidence of AKI (36%), than was the application of SC criteria (21%), which was consistent across the subgroup analyses performed. Furthermore, the use of UO criteria was associated with an earlier diagnosis of AKI (2.4-46.0 h). Both diagnostic modalities accurately predicted risk of AKI-related mortality.
CONCLUSIONS: Evidence suggests that the inclusion of UO criteria provides substantial diagnostic and prognostic value to the detection of AKI.

Post-operative acute kidney injury is a devastating complication with significant morbidity and mortality associated with it. The perioperative anesthesiologist is in a unique position to potentially mitigate the risk of postoperative AKI, however, understanding the pathophysiology, risk factors and preventative strategies is paramount. There are also certain clinical scenarios, where renal replacement therapy may be indicated intraoperatively including severe electrolyte abnormalities, metabolic acidosis and massive volume overload. A multidisciplinary approach including the nephrologist, critical care physician, surgeon and anesthesiologist is necessary to determine the optimal management of these critically ill patients.

UNASSIGNED: Three consensus classifications of acute kidney injury have been published. These are RIFLE (Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease published by the Acute Dialysis Quality Initiative workgroup), AKIN (published by the Acute Kidney Injury Network) and KDIGO (published by the Kidney Disease Improving Global Outcome workgroup). Acute kidney injury has been reported consistently as associated with worsened outcomes. However, toxicant-related acute kidney injury has been excluded from the studies used to validate the classifications of acute kidney injury.
UNASSIGNED: To study whether poisoned patients who develop acute kidney injury, as defined by consensus definitions/classifications, have higher mortality compared to those who did not.
UNASSIGNED: Databases were searched from 2004 to 2019 using the following keywords (KDIGO OR \"Kidney Disease: Improving Global Outcomes\" OR \"Kidney Disease Improving Global Outcomes\" OR AKIN OR \"AKI network\" OR \"Acute kidney Injury Network\" OR ADQI OR RIFLE OR \"Acute dialysis quality initiative\") AND (intoxication OR poisoning OR overdose OR ingestion) AND (AKI OR kidney OR renal OR ARF). If data were available, we used a random-effects meta-analysis model and Fisher\'s exact test to compare mortality in patients according to kidney function definitions (acute kidney injury vs not) and stages (stages vs no acute kidney injury), respectively. If data were available, we assessed the correlation between mortality and renal function (no acute kidney injury, risk/stage 1, injury/stage 2 and failure/stage 3) using the Spearman correlation. If available, we collected the results of statistical analyses in studies that have used acute kidney injury to predict mortality.
UNASSIGNED: Study selection. Thirty-three relevant studies were found, 22/33 retrospective studies (67%) and 11/33 prospective studies (33%). Paraquat was the most frequent toxicant involved (13/33, 39%). We found a disparity between studies regarding the timeframe during which mortality was assessed, the temporality of the renal function considered to predict mortality (initial/worst) and the criteria used to define/grade acute kidney injury across studies. Univariate association between acute kidney injury definitions/stages and mortality. Consensus definitions/staging of acute kidney injury were associated with higher mortality, using univariate analyses, in twenty-eight (RIFLE = 7; AKIN = 12; KDIGO = 9) studies included but not in five (AKIN = 4, KDIGO = 1). When available data were pooled, RIFLE (5 studies), AKIN (16 studies) and KDIGO definitions (8 studies) of acute kidney injury were associated with a higher mortality (Log unadjusted Odds ratios [95%-confidence interval], 2.60 [2.23; 2.97], 2.02 [1.48; 2,52] and 3.22 [2,65; 3.78], respectively). However, we found high heterogeneity (I2=54,7%) and publication bias among studies using AKIN. In ten studies with available data, the correlation between renal function (no acute kidney injury, risk/stage 1, injury/stage 2, failure/stage 3) and mortality was significant in 5 studies (RIFLE = 2; AKIN = 3), but not in five studies (RIFLE = 1; AKIN = 3; KDIGO = 1).Multivariate association between acute kidney injury definitions/stages and mortality. The definitions of acute kidney injury were associated with higher mortality in two studies (RIFLE = 2), but not in four studies (AKIN = 1 and KDIGO = 3. The stages of acute kidney injury (including one or more stages) were associated with higher mortality in four (RIFLE = 1, AKIN = 1 and KDIGO = 2).
UNASSIGNED: All three consensus definitions/classifications were associated independently with increased mortality in poisoning but with disparity between studies reporting acute kidney injury.

Polymyxins are last-resort antibiotics re-emerged to treat infections caused by multidrug resistant (MDR) and extensively drug-resistant (XDR) Gram-negative bacterial infections. However, polymyxin-associated nephrotoxicity has become the main safety concern. Therefore, we conducted this systematic review and meta-analysis on polymyxin-induced nephrotoxicity and its predictors using studies conducted based on the validated RIFLE (Risk, Injury, Failure, Loss of Function and End-stage renal disease) criteria of acute kidney damage. Literature search was carried out through visiting legitimate databases and indexing services including PubMed, MEDLINE (Ovid®), EMBASE (Ovid®), and Scopus to retrieve relevant studies. Following screening and eligibility evaluation, relevant data were extracted from included studies and analyzed using STATA 15.0 and Rev-Man 5.3. Inverse variance method with random effects pooling model was used for the analysis of outcome measures at 95% confidence interval. Besides, meta-regression, meta-influence, and publication bias analyses were conducted. A total of 48 studies involving 6,199 adult patients aged ≥ 18 years were included for systematic review and meta-analysis. The pooled incidence of polymyxin-induced nephrotoxicity was found to be 45% (95% CI: 41- 49%; I2 = 92.52%). Stratifying with RIFLE severity scales, pooled estimates of polymyxin-treated patients identified as \'risk\', \'injury\' and \'failure\' were 17% (95% CI: 14-20%), 13% (95% CI: 11-15%), and 10% (95% CI: 9-11%), respectively. Besides, the pooled incidence of colistin-induced nephrotoxicity was about 48% (95% CI: 42-54%), whereas that of polymyxin B was 38% (95% CI: 32-44%). Likewise, colistin had 37% increased risk of developing nephrotoxicity compared to the polymyxin B treated cohorts (RR = 1.37, 95% CI: 1.13-1.67; I2 = 57%). Older age (AOR = 1.03, 95% CI: 1.01-1.05), daily dose (AOR = 1.46, 95% CI: 1.09-1.96), underlying diabetes mellitus (AOR = 1.81, 95% CI: 1.25-2.63), and concomitant nephrotoxic drugs (AOR = 2.31, 95% CI: 1.79-3.00) were independent risk factors for polymyxin-induced nephrotoxicity. Patients with high serum albumin level were less likely (AOR = 0.69, 95% CI: 0.56-0.85] to experience nephrotoxicity compared to those with low albumin level. Despite the resurgence of these antibiotics for the chemotherapy of MDR/XDR-Gram-negative superbugs, the high incidence of nephrotoxicity has become a contemporary clinical concern. Being elderly, high daily dose, having underlying diseases such as diabetes, and use of concomitant nephrotoxic drugs were independent predictors of nephrotoxicity. Therefore, therapeutic drug monitoring should be done to these patients to outweigh the potential benefits of polymyxin therapy from its risk.

In May 2004, a new classification, the RIFLE (Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease) classification, was proposed in order to define and stratify the severity of acute kidney injury (AKI). This system relies on changes in the serum creatinine (SCr) or glomerular filtration rates and/or urine output, and it has been largely demonstrated that the RIFLE criteria allows the identification of a significant proportion of AKI patients hospitalized in numerous settings, enables monitoring of AKI severity, and is a good predictor of patient outcome. Three years later (March 2007), the Acute Kidney Injury Network (AKIN) classification, a modified version of the RIFLE, was released in order to increase the sensitivity and specificity of AKI diagnosis. Until now, the benefit of these modifications for clinical practice has not been clearly demonstrated. Here we provide a critical and comprehensive discussion of the two classifications for AKI, focusing on the main differences, advantages and limitations.