Hospital-acquired and community-acquired acute renal failure in hospitalized Chinese: a ten-year review

Eleutherococcus senticosus Alleviates Aristolochic-Acid-Induced Acute Kidney Damage by Inhibiting the NLRP3/IL-1β Signaling Pathway in Mice

Eleutherococcus senticosus (ES) exerts various pharmacological effects, including renoprotection in a rat model of renal ischemia-reperfusion injury. However, the mechanisms of these effects remain unclear. Therefore, we investigated the effects and mechanisms of ES on aristolochic acid (AA)-induced acute kidney injury in mice. The experimental mice were divided into the control group, the model group (AA-induced acute kidney injury model), the model + ES group (Eleutherococcus senticosus boiled-free granules treated by gavage for two weeks), the model + fasudil group (fasudil administered intraperitoneally for three days), and the model + ES + fasudil group. After AA intervention in normal mice, the expression of ASC and NLRP3 and the levels of IL-1β, IL-18, and TNF-α were significantly elevated in mouse renal tissues (P < 0.05). However, AA-induced renal dysfunction was ameliorated by both ES and fasudil, which was confirmed by the decrease in serum creatinine and blood urea nitrogen levels, as well as by renal histopathological abnormalities such as renal tubule dilation and tubular formation. In addition, the inflammatory response of AA-induced renal inflammation was inhibited by both ES and fasudil, and the expression of ASC and NLRP3 and the levels of IL-1β, IL-18, and TNF-α were significantly higher in mouse renal tissues after the treatment of either ES or fasudil (P < 0.05). ES may be a potential treatment agent for aristolochic-acid-triggered nephropathy, with inhibition of the NLRP3/IL-1β as one plausible underlying mechanism.

Epidemiology and Clinical Outcomes of Community-Acquired Acute Kidney Injury in the Emergency Department: A Multisite Retrospective Cohort Study

RATIONALE & OBJECTIVE

The prevalence of community-acquired acute kidney injury (CA-AKI) in the United States and its clinical consequences are not well described. Our objective was to describe the epidemiology of CA-AKI and the associated clinical outcomes.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

178,927 encounters by 139,632 adults at 5 US emergency departments (EDs) between July 1, 2017, and December 31, 2022.

PREDICTORS

CA-AKI identified using KDIGO (Kidney Disease: Improving Global Outcomes) serum creatinine (Scr)-based criteria.

OUTCOMES

For encounters resulting in hospitalization, the in-hospital trajectory of AKI severity, dialysis initiation, intensive care unit (ICU) admission, and death. For all encounters, occurrence over 180 days of hospitalization, ICU admission, new or progressive chronic kidney disease, dialysis initiation, and death.

ANALYTICAL APPROACH

Multivariable logistic regression analysis to test the association between CA-AKI and measured outcomes.

RESULTS

For all encounters, 10.4% of patients met the criteria for any stage of AKI on arrival to the ED. 16.6% of patients admitted to the hospital from the ED had CA-AKI on arrival to the ED. The likelihood of AKI recovery was inversely related to CA-AKI stage on arrival to the ED. Among encounters for hospitalized patients, CA-AKI was associated with in-hospital dialysis initiation (OR, 6.2; 95% CI, 5.1-7.5), ICU admission (OR, 1.9; 95% CI, 1.7-2.0), and death (OR, 2.2; 95% CI, 2.0-2.5) compared with patients without CA-AKI. Among all encounters, CA-AKI was associated with new or progressive chronic kidney disease (OR, 6.0; 95% CI, 5.6-6.4), dialysis initiation (OR, 5.1; 95% CI, 4.5-5.7), subsequent hospitalization (OR, 1.1; 95% CI, 1.1-1.2) including ICU admission (OR, 1.2; 95% CI, 1.1-1.4), and death (OR, 1.6; 95% CI, 1.5-1.7) during the subsequent 180 days.

LIMITATIONS

Residual confounding. Study implemented at a single university-based health system. Potential selection bias related to exclusion of patients without an available baseline Scr measurement. Potential ascertainment bias related to limited repeat Scr data during follow-up after an ED visit.

CONCLUSIONS

CA-AKI is a common and important entity that is associated with serious adverse clinical consequences during the 6-month period after diagnosis.

PLAIN-LANGUAGE SUMMARY

Acute kidney injury (AKI) is a condition characterized by a rapid decline in kidney function. There are many causes of AKI, but few studies have examined how often AKI is already present when patients first arrive to an emergency department seeking medical attention for any reason. We analyzed approximately 175,000 visits to Johns Hopkins emergency departments and found that AKI is common on presentation to the emergency department and that patients with AKI have increased risks of hospitalization, intensive care unit admission, development of chronic kidney disease, requirement of dialysis, and death in the first 6 months after diagnosis. AKI is an important condition for health care professionals to recognize and is associated with serious adverse outcomes.

Mice kidney biometabolic process analysis after cantharidin exposure using widely-targeted metabolomics combined with network pharmacology

Cantharidin (CTD) is a principal bioactive component of traditional Chinese medicine Mylabris used in cancer treatment. However, CTD clinical application is limited due to nephrotoxicity, and the mechanism is unknown. The present study used widely-targeted metabolomics, network pharmacology, and cell experiments to investigate the nephrotoxicity mechanism after CTD exposure. In mice exposed to CTD, serum creatinine and urea nitrogen levels increased with renal injury. Then, 74 differential metabolites were detected, including 51 up-regulated and 23 down-regulated metabolites classified as amino acids, small peptides, fatty acyl, arachidonic acid metabolite, organic acid, and nucleotides. Sixteen metabolic pathways including tyrosine, sulfur, and pyrimidine metabolism were all disrupted in the kidney. Furthermore, network pharmacology revealed that 258 metabolic targets, and pathway enrichment indicated that CTD could activate oxidative phosphorylation and oxidative stress (OS). Subsequently, HK-2 cell experiments demonstrated that CTD could reduce superoxide dismutase while increasing malondialdehyde levels. In conclusion, after CTD exposure, biometabolic processes may be disrupted with renal injury in mice, resulting in oxidative phosphorylation and OS.

Loop Diuretics Are Associated with Increased Risk of Hospital-Acquired Acute Kidney Injury in Adult Patients: A Retrospective Study

Background: The association between loop diuretics and acute kidney injury (AKI) remains unclear. Methods: The population studied was selected from the Epidemiology of AKI in Chinese Hospitalized patients (EACH) study. Exposure to loop diuretics was defined as any filled prescription prior to the date when AKI was detected in patients with HA-AKI, and prior to the last date of SCr testing in those without AKI. The outcome was AKI, defined by the Kidney Disease Improving Global Outcomes criteria. Associations between loop diuretics and HA-AKI were examined by Cox proportional hazards models adjusted for baseline and time-dependent covariates. Results: Of the 150,020 patients, 16,437 (11.0%) were prescribed loop diuretics, and 5717 (3.8%) experienced HA-AKI events. The crude rates of HA-AKI in patients who were and were not prescribed loop diuretics were 1632 (9.9%) and 3262 (2.8%), respectively. A multivariate cox proportional hazards analysis showed that exposure to loop diuretics was associated with significantly increased risks of HA-AKI compared with non-users (hazard ratio (HR), 1.61; 95% CI (confidence interval), 1.55–1.67), other diuretics (HR, 1.09; 95% CI, 1.03–1.15), and osmotic diuretics (HR, 1.30; 95% CI, 1.20–1.42). Compared with other diuretics, the use of loop diuretics was associated with higher risks of HA-AKI in women, in patients without hypertension, in patients without heart failure, in patients without liver cirrhosis, and in patients not requiring surgery. Conclusions: Loop diuretics are widely used and are associated with increased risks of HA-AKI in hospitalized adults. Renal function should be more closely monitored during the use of loop diuretics.

Endoplasmic reticulum stress contributes to autophagy and apoptosis in cantharidin-induced nephrotoxicity

Mylabris, as a natural product of traditional Chinese medicine (TCM), exhibiting typical antitumor activity, and cantharidin (CTD) is the major bioactive component. However, drug-induced nephrotoxicity (DIN) extremely limited its clinical application. In this study, we proved that activation of the endoplasmic reticulum (ER) stress-dependent PERK/CHOP pathway exerts a toxic role in rats and HK-2 cells through inducing autophagy and apoptosis. Results showed that CTD could cause renal function damage, cytotoxicity, and apoptosis. The ER dilatation and autolysosomes were observed after CTD treatment. Furthermore, the distribution of LC3, ATF4, and CHOP proteins was observed in the nucleus and cytoplasm. In addition, the mRNA levels of ER stress-regulated genes (PERK, eIF2α, CHOP, and ATF4) were increased, and the expression levels of GRP78, ATF4, CHOP, LC3, Beclin-1, Atg3, Atg7, Caspase 3, and Bax/Bcl-2 proteins were increased both in vitro and in vivo. Consistently, this upregulation could be inhibited by an ER stress inhibitor 4-Phenylbutyric acid (4-PBA), indicating that ER stress is partly responsible for activation of autophagy and apoptosis in CTD-induced DIN. In conclusion, CTD could induce DIN by triggering ER stress, further activating autophagy and apoptosis both in vivo and in vitro.

Nephroprotective potential of Panduratin A against colistin-induced renal injury via attenuating mitochondrial dysfunction and cell apoptosis

Colistin is a last-resort polypeptide antibiotic widely used to treat against multidrug-resistant Gram-negative bacterial infections. However, this treatment is associated with nephrotoxicity. The aim of this study was to examine the potential protective effect of panduratin A, a bioactive compound of Boesenbergia rotunda, on colistin-induced nephrotoxicity in both in vivo and in vitro models. Intraperitoneal injection of 15 mg/kg colistin for 7 days markedly promoted renal tubular degeneration, increased blood urea nitrogen (BUN) levels, and upregulated the expression of renal injury biomarker and apoptosis proteins. In addition, treatment with colistin increased oxidative stress and apoptosis in mice kidney tissues. Interestingly, these defects were attenuated when co-administered of colistin with panduratin A (2.5 or 25 mg/kg). The underlying mechanisms of panduratin A attenuating colistin toxicity was investigated in human renal proximal tubular cells (RPTEC/TERT1). The mechanisms by which colistin-triggered cytotoxicity was determined by analysis of cell death, reactive oxygen species (ROS) levels, mitochondria function as well as the expression of proteins related to apoptosis pathway. Colistin treatment (200 µg/ml) significantly increased cell apoptosis, elevated ROS production, reduced mitochondrial membrane potential, and decreased anti-apoptotic protein (Bcl-2) expression. These effects were notably suppressed by co-treatment with panduratin A (5 μM). Collectively, panduratin A exerts as a novel nephroprotective agent to protect against colistin-induced renal injury by attenuating mitochondrial damage and renal cell apoptosis.

Epidemiology and outcomes of dialysis requiring acute kidney injury: A single-center study

OBJECTIVES

Acute kidney injury (AKI) is a common diagnosis in hospitalized patients. Dialysis requiring AKI (AKI-D) is associated with adverse outcomes. This study aims to know the clinical profile and short-term outcomes at 3 months, in patients with AKI-D, at our center.

METHODS

A prospective observational study was done of all the patients admitted with AKI-D for 2 years, from July 2018 to June 2020. We recorded clinical parameters at baseline and postdischarge follow-up at 3 months.

RESULTS

One hundred twenty-eight patients had AKI-D over 2 years. Then, 116 (90.6%) patients had community-acquired AKI (CAAKI), and 12 (9.4%) patients had hospital-acquired AKI. The underlying causes of AKI-D were: toxins in 48 (37.5%), sepsis in 31 (24.2%), acute kidney disease in 15 (11.7%), acute gastroenteritis (AGE) in 9 (7%), and cardiogenic shock in 7 (5.5%) patients. The mean values of intact parathyroid hormone (available in 32% of patients) were 268 pg/mL. Intermittent hemodialysis was the commonest mode of dialysis (85.2%). A kidney biopsy was done in 23 (18%) patients. The most common diagnosis on kidney biopsy was glomerulonephritis (GN) in 12 patients (crescentic GN-9 and IgA nephropathy-3), followed by acute tubule-interstitial nephritis in 6 patients. In-hospital mortality was 29.7%. Overall, 39% regained serum creatinine in the normal range at 3 months, 36.7% died, 14.1% reached chronic kidney disease (CKD), 7.8% lost to follow-up, and 2.3% had reached end-stage renal disease.

CONCLUSION

The majority of AKI-D at our center was CAAKI. A significant chunk of AKI-D (68.7%) was caused by preventable causes like toxins, sepsis, and AGE. Dysregulation of mineral metabolism was conspicuous. In chemical toxin vs. biological toxins and undifferentiated sepsis vs. the identifiable cause of sepsis, formers had significantly more in-hospital mortality than the latter ones. AKI-D is associated with high in-hospital mortality, total mortality, and risk of progression to CKD at 3 months.

Drug-Induced Hospital-Acquired Acute Kidney Injury in China: A Multicenter Cross-Sectional Survey

INTRODUCTION

Drug-induced acute kidney injury (D-AKI) is one of the important types of AKI. The incidence of D-AKI in China has rarely been studied.

OBJECTIVE

This study aims to explore the disease burden, related drugs, and risk factors of D-AKI.

METHODS

A nationwide cross-sectional survey was conducted in adult patients from 23 academic hospitals in 17 provinces in China. Suspected AKI was screened based on serum creatinine changes in accordance with the 2012 Kidney Disease: Improving Global Outcomes Clinical Practice Guideline for AKI, patients who met the diagnosis of hospital-acquired AKI in January and July of 2014 were defined. Suspected AKI was firstly evaluated for the possibility of D-AKI by pharmacists using the Naranjo Scale and finally defined as D-AKI by nephrologists through reviewing AKI clinical features.

RESULTS

Altogether 280,255 hospitalized patients were screened and 1,960 cases were diagnosed as hospital-acquired AKI, among which 735 cases were defined as having D-AKI (37.50%, 735/1,960) with an in-hospital mortality rate of 13.88% and 54.34% of the survivors did not achieve full renal recovery. 1,642 drugs were related to AKI in these patients. Anti-infectives, diuretics, and proton pump inhibitors were the top 3 types of drugs relevant to D-AKI, accounting for 66.63% cumulatively. Besides age, AKI staging, severe disease, hypoalbuminemia, plasma substitute, and carbapenem related D-AKI were independent risk factors for in-hospital mortality of D-AKI patients.

CONCLUSION

In China, D-AKI has caused a substantial medical burden. Efforts should be made to pursue nephrotoxic drug stewardship to minimize attributable risk and improve the prevention, diagnosis, and treatment of D-AKI.

Frequency of Risk Factors and Outcome of Hospital-Acquired Acute Kidney Injury

OBJECTIVE

To determine the frequencies of risk factors and the ultimate outcomes of ccute kidney injury (AKI) among hospitalized patients.

MATERIALS AND METHODOLOGY

This prospective, observational study was carried out from September 15, 2018, to March 14, 2019. All admitted patients, both male and female, with AKI, were included. Those with chronic kidney disease (CKD), small size echogenic kidneys (on ultrasonography, performed on admission), and recent history of urological intervention were excluded from the study. All patients were assessed for etiological factors (sepsis, gastroenteritis, surgical, and obstetrical) and outcome (improved, progression to CKD, or expired).

RESULTS

Out of a total of 230, most patients were aged between 20-50 years with a mean age of 38.99 ± 7.61 years. Males were 144 (62.61%) and females were 86 (37.39%). About 78 (33.91%) patients were hypertensive while 65 (28.26%) were diabetic. The cause of hospital-acquired AKI was found to be sepsis in most (71.73%, n=165) of the cases, followed by gastroenteritis (10.00%, n=23), surgical (9.56%, n=22), and obstetric (8.69%, n=20) causes. When the outcome was assessed, 10 (4.35%) patients expired, 154 (66.96%) improved completely, while 66 (28.69%) progressed to CKD.

CONCLUSION

This study has shown that sepsis is the most common cause of AKI in patients admitted to the hospital. So we recommend that proper steps should be taken to ensure adequate hospital care for avoiding such outcomes in hospitalized patients, and further decrease mortality.

Development and external validation of an acute kidney injury risk score for use in the general population

Background

Improving recognition of patients at increased risk of acute kidney injury (AKI) in the community may facilitate earlier detection and implementation of proactive prevention measures that mitigate the impact of AKI. The aim of this study was to develop and externally validate a practical risk score to predict the risk of AKI in either hospital or community settings using routinely collected data.

Methods

Routinely collected linked datasets from Tayside, Scotland, were used to develop the risk score and datasets from Kent in the UK and Alberta in Canada were used to externally validate it. AKI was defined using the Kidney Disease: Improving Global Outcomes serum creatinine–based criteria. Multivariable logistic regression analysis was performed with occurrence of AKI within 1 year as the dependent variable. Model performance was determined by assessing discrimination (C-statistic) and calibration.

Results

The risk score was developed in 273 450 patients from the Tayside region of Scotland and externally validated into two populations: 218 091 individuals from Kent, UK and 1 173 607 individuals from Alberta, Canada. Four variables were independent predictors for AKI by logistic regression: older age, lower baseline estimated glomerular filtration rate, diabetes and heart failure. A risk score including these four variables had good predictive performance, with a C-statistic of 0.80 [95% confidence interval (CI) 0.80–0.81] in the development cohort and 0.71 (95% CI 0.70–0.72) in the Kent, UK external validation cohort and 0.76 (95% CI 0.75–0.76) in the Canadian validation cohort.

Conclusion

We have devised and externally validated a simple risk score from routinely collected data that can aid both primary and secondary care physicians in identifying patients at high risk of AKI.

Kidney function and nephrotoxic drug use among older home-dwelling persons with or without diabetes in Finland

Background

Due to these changes in kidney function, aging kidneys are more prone to drug-induced impairments in renal properties. Diabetes has been associated with the declined kidney function and an elevated risk of renal failure. The aim of this study is to compare kidney function and potentially nephrotoxic drug use among home-dwelling older persons with or without diabetes.

Methods

A total of 259 persons with and 259 persons without diabetes and aged ≥65 years were randomly selected to participate in a health examination with complete data gathered from 363 individuals (187 with diabetes and 176 without diabetes). The estimated glomerular filtration rate (eGFR) was calculated using CKD-EPI equation. Each participant was categorized based on the nephrotoxic profile of their medications.

Results

There were no differences in mean eGFR values (77.5 ± 18.8 vs. 80.5 ± 14.8 ml/min/1.73m², p = 0.089) or in the proportion of participants with eGFR < 60 ml/min/1.73m² among persons with diabetes (16% vs. 10%, p = 0.070), compared to persons without diabetes. Potentially nephrotoxic drug use was similar between the groups. The mean number of potentially nephrotoxic drugs was 1.06 ± 0.88 in those with and 0.97 ± 1.05 in those without diabetes (p = 0.39).

Conclusions

The kidney function of older persons with diabetes does not differ from that of older persons without diabetes and furthermore potentially nephrotoxic drug use seem to play only a minor role in the decline in kidney function among home-dwelling persons in the Inner-Savo district.

Acute Kidney Injury in the Outpatient Setting Associates with Risk of End-Stage Renal Disease and Death in Patients with CKD

Current acute kidney injury (AKI) diagnostic criteria are restricted to the inpatient setting. We proposed a new AKI diagnostic algorithm for the outpatient setting and evaluate whether outpatient AKI (AKIOPT) modifies the disease course among patients with chronic kidney disease (CKD) enrolled in the national predialysis registry. AKIOPT was detected when a 50% increase in serum creatinine level or 35% decline in eGFR was observed in the 180-day period prior to enrollment in the predialysis care program. Outcomes were progression to end-stage renal disease (ESRD) and all-cause mortality. Association analyses were performed using multiple Cox regression and coarsened exact matching (CEM) analysis. Among 6,046 patients, 31.5% (1,905 patients) had developed AKIOPT within the 180-day period before enrollment. The adjusted hazard ratios of the 1-year and overall risk of ESRD among patients with preceding AKIOPT compared with those without AKIOPT were 2.61 (95% CI: 2.15-3.18) and 1.97 (1.72-2.26), respectively. For 1-year and overall risk of all-cause mortality, patients with AKIOPT had respectively a 141% (95% CI: 89-209%) and 84% (56-117%) higher risk than those without AKIOPT. This statistical inference remained robust in CEM analysis. We also discovered a complete reversal in the eGFR slope before and after the AKIOPT from -10.61 ± 0.32 to 0.25 ± 0.30 mL/min/1.73 m2 per year; however, the loss of kidney function is not recovered. The new AKIOPT diagnostic algorithm provides prognostic insight in patients with CKD.

Acute kidney injury in non-critical care setting: elaboration and validation of an in-hospital death prognosis score

Background

Acute kidney injury (AKI) is still characterized by a high mortality rate. While most patients with AKI are admitted in conventional medical units, current available data are still obtained from studies designed for patients admitted in intensive care units (ICU). Our study aimed to elaborate and validate an in-hospital death prognosis score for AKI admitted in conventional medical care units.

Methods

We included two prospective cohorts of consecutive patients with AKI admitted between 2001 and 2004 (elaboration cohort (EC)) and between 2010 and 2014 (validation cohort (VC)). We developed a scoring system from clinical and biological parameters recorded at admission from the EC to predict in-hospital mortality. This score was then tested for validation in the VC.

Results

Three-hundred and twenty-three and 534 patients were included in the EC and VC cohorts, respectively. The proportion of in-hospital death were 15.5% (EC) and 8.9% (VC), mainly due to sepsis. The parameters independently associated with the in-hospital death in the EC were Glasgow score, oxygen requirement, fluid overload, blood diastolic pressure, multiple myeloma and prothrombin time. The in-hospital death prognosis score AUC was 0.845 +/− 0.297 (p < 0.001) after validation in the VC.

Conclusions

Our in-hospital death prognosis score is the first to be prospectively developed and validated for AKI admitted in a conventional medical care unit. Based on current parameters, easily collected at time of admission, this score could be a useful tool for physicians and nephrologists to determine the in-hospital death prognosis of this AKI population.

Clinical Characteristics and Outcomes of Community-Acquired versus Hospital-Acquired Acute Kidney Injury: A Meta-Analysis

BACKGROUND

The different clinical characteristics of community-acquired acute kidney injury (CA-AKI) versus hospital-acquired AKI (HA-AKI) have remained inconclusive, and thus, a meta-analysis was conducted to summarize and quantify the clinical significance distinguishing the 2 types of AKI.

METHODS

We identified observational studies reporting the clinical characteristics and prognosis of HA-AKI and CA-AKI. ORs and mean differences (MDs) were extracted for each outcome and the results aggregated. The primary outcome was defined as the mortality rate; renal recovery, oliguria incidence, dialysis, intensive care unit (ICU) requirement, and length of hospital stay were secondary outcomes.

RESULTS

Fifteen eligible studies involving 46,157 patients (22,791 CA-AKI patients and 23,366 HA-AKI patients) were included. Mortality was significantly lower in CA-AKI than in HA-AKI patients, with an OR of 0.43 (95% CI 0.35-0.53). The incidence of oliguria and need for ICU were also lower in CA-AKI patients (OR 0.58, 95% CI 0.38-0.88; OR 0.24, 95% CI 0.14-0.40, respectively). CA-AKI patients had a shorter hospital stay (MD -9.42, 95% CI -13.73 to -5.12). The renal recovery rate and dialysis need between CA- and HA-AKI were similar (OR 1.27, 95% CI 0.53-3.02; OR 1.05, 95% CI 0.82-1.34, respectively).

CONCLUSIONS

CA-AKI showed better clinical manifestations with a lower incidence of oliguria, reduced risk of ICU treatment, and shorter hospital stay. Mortality associated with CA-AKI was lower compared with HA-AKI, indicating a better prognosis. The rate of renal recovery and need for dialysis showed no significant difference between the 2 groups.

Krt5+ urothelial cells are developmental and tissue repair progenitors in the kidney

Congenital urinary tract obstruction (UTO) is the leading cause of chronic kidney disease in children; however, current management strategies do not safeguard against progression to end-stage renal disease, highlighting the need for interventions to limit or reverse obstructive nephropathy. Experimental UTO triggers renal urothelial remodeling that culminates in the redistribution of basal keratin 5-positive (Krt5⁺) renal urothelial cells (RUCs) and the generation of uroplakin-positive (Upk)⁺ RUCs that synthesize a protective apical urothelial plaque. The cellular source of Upk⁺ RUCs is currently unknown, limiting the development of strategies to promote renal urothelial remodeling as a therapeutic approach. In the present study, we traced the origins of adult Upk⁺ RUCs during normal development and in response to UTO. Fate mapping analysis demonstrated that adult Upk⁺ RUCs derive from embryonic and neonatal Krt5⁺ RUCs, whereas Krt5⁺ RUCs lose this progenitor capacity and become lineage restricted by postnatal day 14. However, in response to UTO, postnatal day 14-labeled adult Krt5⁺ RUCs break their lineage restriction and robustly differentiate into Upk⁺ RUCs. Thus, Krt5⁺ RUCs drive renal urothelial formation during normal ontogeny and after UTO by differentiating into Upk⁺ RUCs in a temporally restricted manner.

Nephrotoxicity and Chinese Herbal Medicine

Chinese herbal medicine has been practiced for the prevention, treatment, and cure of diseases for thousands of years. Herbal medicine involves the use of natural compounds, which have relatively complex active ingredients with varying degrees of side effects. Some of these herbal medicines are known to cause nephrotoxicity, which can be overlooked by physicians and patients due to the belief that herbal medications are innocuous. Some of the nephrotoxic components from herbs are aristolochic acids and other plant alkaloids. In addition, anthraquinones, flavonoids, and glycosides from herbs also are known to cause kidney toxicity. The kidney manifestations of nephrotoxicity associated with herbal medicine include acute kidney injury, CKD, nephrolithiasis, rhabdomyolysis, Fanconi syndrome, and urothelial carcinoma. Several factors contribute to the nephrotoxicity of herbal medicines, including the intrinsic toxicity of herbs, incorrect processing or storage, adulteration, contamination by heavy metals, incorrect dosing, and interactions between herbal medicines and medications. The exact incidence of kidney injury due to nephrotoxic herbal medicine is not known. However, clinicians should consider herbal medicine use in patients with unexplained AKI or progressive CKD. In addition, exposure to herbal medicine containing aristolochic acid may increase risk for future uroepithelial cancers, and patients require appropriate postexposure screening.

The Japanese clinical practice guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention is necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search.

The Japanese Clinical Practice Guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention are necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search.

Acute kidney injury: Epidemiology, outcomes, complications, and therapeutic strategies

Acute kidney injury (AKI) is one of the most common serious complications for all hospital admissions, with its incidence increasing among hospitalized patients, particularly those in the intensive care unit. Despite significant improvements in critical care and dialysis technology, AKI is associated with an increased risk of short- and long-term mortality, prolonged hospital stays, and dialysis dependence. These risks are particularly relevant for critically ill patients with AKI severe enough to require renal replacement therapy (RRT). No specific pharmacologic treatment has been established to treat AKI. Hence, the mainstay treatment for patients with AKI is RRT even though there are still several problematic issues regarding its use including RRT modality, dose, and timing. Recently, the impact of AKI on an increased risk of progression to chronic kidney disease (CKD) and end-stage renal disease requiring dialysis or transplantation is attracting increased attention.

MiR-30c regulates cisplatin-induced apoptosis of renal tubular epithelial cells by targeting Bnip3L and Hspa5

As a common anticancer drug, cisplatin has been widely used for treating tumors in the clinic. However, its side effects, especially its nephrotoxicity, noticeably restrict the application of cisplatin. Therefore, it is imperative to investigate the mechanism of renal injury and explore the corresponding remedies. In this study, we showed the phenotypes of the renal tubules and epithelial cell death as well as elevated cleaved-caspase3- and TUNEL-positive cells in rats intraperitoneally injected with cisplatin. Similar cisplatin-induced cell apoptosis was found in HK-2 and NRK-52E cells exposed to cisplatin as well. In both models of cisplatin-induced apoptosis in vivo and in vitro, quantitative PCR data displayed reductions in miR-30a-e expression levels, indicating that miR-30 might be involved in regulating cisplatin-induced cell apoptosis. This was further confirmed when the effects of cisplatin-induced cell apoptosis were found to be closely correlated with alterations in miR-30c expression, which were manipulated by transfection of either the miR-30c mimic or miR-30c inhibitor in HK-2 and NRK-52E cells. Using bioinformatics tools, including TargetScan and a gene expression database (Gene Expression Omnibus), Adrb1, Bnip3L, Hspa5 and MAP3K12 were predicted to be putative target genes of miR-30c in cisplatin-induced apoptosis. Subsequently, Bnip3L and Hspa5 were confirmed to be the target genes after determining the expression of these putative genes following manipulation of miR-30c expression levels in HK-2 cells. Taken together, our current experiments reveal that miR-30c is certainly involved in regulating the renal tubular cell apoptosis induced by cisplatin, which might supply a new strategy to minimize cisplatin-induced nephrotoxicity.

Predicting AKI in emergency admissions: an external validation study of the acute kidney injury prediction score (APS)

OBJECTIVES

Hospital-acquired acute kidney injury (HA-AKI) is associated with a high risk of mortality. Prediction models or rules may identify those most at risk of HA-AKI. This study externally validated one of the few clinical prediction rules (CPRs) derived in a general medicine cohort using clinical information and data from an acute hospitals electronic system on admission: the acute kidney injury prediction score (APS).

DESIGN, SETTING AND PARTICIPANTS

External validation in a single UK non-specialist acute hospital (2013-2015, 12 554 episodes); four cohorts: adult medical and general surgical populations, with and without a known preadmission baseline serum creatinine (SCr).

METHODS

Performance assessed by discrimination using area under the receiver operating characteristic curves (AUCROC) and calibration.

RESULTS

HA-AKI incidence within 7 days (kidney disease: improving global outcomes (KDIGO) change in SCr) was 8.1% (n=409) of medical patients with known baseline SCr, 6.6% (n=141) in those without a baseline, 4.9% (n=204) in surgical patients with baseline and 4% (n=49) in those without. Across the four cohorts AUCROC were: medical with known baseline 0.65 (95% CIs 0.62 to 0.67) and no baseline 0.71 (0.67 to 0.75), surgical with baseline 0.66 (0.62 to 0.70) and no baseline 0.68 (0.58 to 0.75). For calibration, in medicine and surgical cohorts with baseline SCr, Hosmer-Lemeshow p values were non-significant, suggesting acceptable calibration. In the medical cohort, at a cut-off of five points on the APS to predict HA-AKI, positive predictive value was 16% (13-18%) and negative predictive value 94% (93-94%). Of medical patients with HA-AKI, those with an APS ≥5 had a significantly increased risk of death (28% vs 18%, OR 1.8 (95% CI 1.1 to 2.9), p=0.015).

CONCLUSIONS

On external validation the APS on admission shows moderate discrimination and acceptable calibration to predict HA-AKI and may be useful as a severity marker when HA-AKI occurs. Harnessing linked data from primary care may be one way to achieve more accurate risk prediction.

Community-Acquired Acute Kidney Injury: A Nationwide Survey in China

BACKGROUND

This study aimed to describe the burden of community-acquired acute kidney injury (AKI) in China based on a nationwide survey about AKI.

STUDY DESIGN

Cross-sectional and retrospective study.

SETTING & PARTICIPANTS

A national sample of 2,223,230 hospitalized adult patients from 44 academic/local hospitals in Mainland China was used. AKI was defined according to the 2012 KDIGO AKI creatinine criteria or an increase or decrease in serum creatinine level of 50% during the hospital stay. Community-acquired AKI was identified when a patient had AKI that could be defined at hospital admission.

PREDICTORS

The rate, cause, recognition, and treatment of community-acquired AKI were stratified according to hospital type, latitude, and economic development of the regions in which the patients were admitted.

OUTCOMES

All-cause in-hospital mortality and recovery of kidney function at hospital discharge.

RESULTS

4,136 patients with community-acquired AKI were identified during the 2 single-month snapshots (January 2013 and July 2013). Of these, 2,020 (48.8%) had cases related to decreased kidney perfusion; 1,111 (26.9%), to intrinsic kidney disease; and 499 (12.1%), to urinary tract obstruction. In the north versus the south, more patients were exposed to nephrotoxins or had urinary tract obstructions. 536 (13.0%) patients with community-acquired AKI had indications for renal replacement therapy (RRT), but only 347 (64.7%) of them received RRT. Rates of timely diagnosis and appropriate use of RRT were higher in regions with higher per capita gross domestic product. All-cause in-hospital mortality was 7.3% (295 of 4,068). Delayed AKI recognition and being located in northern China were independent risk factors for in-hospital mortality, and referral to nephrology providers was an independent protective factor.

LIMITATIONS

Possible misclassification of AKI and community-acquired AKI due to nonstandard definitions and missing data for serum creatinine.

CONCLUSIONS

The features of community-acquired AKI varied substantially in different regions of China and were closely linked to the environment, economy, and medical resources.

National Veterans Health Administration inpatient risk stratification models for hospital-acquired acute kidney injury

OBJECTIVE

Hospital-acquired acute kidney injury (HA-AKI) is a potentially preventable cause of morbidity and mortality. Identifying high-risk patients prior to the onset of kidney injury is a key step towards AKI prevention.

MATERIALS AND METHODS

A national retrospective cohort of 1,620,898 patient hospitalizations from 116 Veterans Affairs hospitals was assembled from electronic health record (EHR) data collected from 2003 to 2012. HA-AKI was defined at stage 1+, stage 2+, and dialysis. EHR-based predictors were identified through logistic regression, least absolute shrinkage and selection operator (lasso) regression, and random forests, and pair-wise comparisons between each were made. Calibration and discrimination metrics were calculated using 50 bootstrap iterations. In the final models, we report odds ratios, 95% confidence intervals, and importance rankings for predictor variables to evaluate their significance.

RESULTS

The area under the receiver operating characteristic curve (AUC) for the different model outcomes ranged from 0.746 to 0.758 in stage 1+, 0.714 to 0.720 in stage 2+, and 0.823 to 0.825 in dialysis. Logistic regression had the best AUC in stage 1+ and dialysis. Random forests had the best AUC in stage 2+ but the least favorable calibration plots. Multiple risk factors were significant in our models, including some nonsteroidal anti-inflammatory drugs, blood pressure medications, antibiotics, and intravenous fluids given during the first 48 h of admission.

CONCLUSIONS

This study demonstrated that, although all the models tested had good discrimination, performance characteristics varied between methods, and the random forests models did not calibrate as well as the lasso or logistic regression models. In addition, novel modifiable risk factors were explored and found to be significant.

Epidemiology and Clinical Correlates of AKI in Chinese Hospitalized Adults

BACKGROUND AND OBJECTIVES

Comprehensive epidemiologic data on AKI are particularly lacking in Asian countries. This study sought to assess the epidemiology and clinical correlates of AKI among hospitalized adults in China.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a multicenter retrospective cohort study of 659,945 hospitalized adults from a wide range of clinical settings in nine regional central hospitals across China in 2013. AKI was defined and staged according to Kidney Disease Improving Global Outcomes criteria. The incidence of AKI in the cohort was estimated using a novel two-step approach with adjustment for the frequency of serum creatinine tests and other potential confounders. Risk factor profiles for hospital-acquired (HA) and community-acquired (CA) AKI were examined. The in-hospital outcomes of AKI, including mortality, renal recovery, length of stay, and daily cost, were assessed.

RESULTS

The incidence of CA-AKI and HA-AKI was 2.5% and 9.1%, respectively, giving rise to an overall incidence of 11.6%. Although the risk profiles for CA-AKI and HA-AKI differed, preexisting CKD was a major risk factor for both, contributing to 20% of risk in CA-AKI and 12% of risk in HA-AKI. About 40% of AKI cases were possibly drug-related and 16% may have been induced by Chinese traditional medicines or remedies. The in-hospital mortality of AKI was 8.8%. The risk of in-hospital death was higher among patients with more severe AKI. Preexisting CKD and need for intensive care unit admission were associated with higher death risk in patients at any stage of AKI. Transiency of AKI did not modify the risk of in-hospital death. AKI was associated with longer length of stay and higher daily costs, even after adjustment for confounders.

CONCLUSION

AKI is common in hospitalized adults in China and is associated with significantly higher in-hospital mortality and resource utilization.

A Prospective International Multicenter Study of AKI in the Intensive Care Unit

BACKGROUND AND OBJECTIVES

AKI is frequent and is associated with poor outcomes. There is limited information on the epidemiology of AKI worldwide. This study compared patients with AKI in emerging and developed countries to determine the association of clinical factors and processes of care with outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This prospective observational study was conducted among intensive care unit patients from nine centers in developed countries and five centers in emerging countries. AKI was defined as an increase in creatinine of ≥0.3 mg/dl within 48 hours.

RESULTS

Between 2008 and 2012, 6647 patients were screened, of whom 1275 (19.2%) developed AKI. A total of 745 (58% of those with AKI) agreed to participate and had complete data. Patients in developed countries had more sepsis (52.1% versus 38.0%) and higher Acute Physiology and Chronic Health Evaluation (APACHE) scores (mean±SD, 61.1±27.5 versus 51.1±25.2); those from emerging countries had more CKD (54.3% versus 38.3%), GN (6.3% versus 0.9%), and interstitial nephritis (7.0% versus 0.6%) (all P<0.05). Patients from developed countries were less often treated with dialysis (15.5% versus 30.2%; P<0.001) and started dialysis later after AKI diagnosis (2.0 [interquartile range, 0.75-5.0] days versus 0 [interquartile range, 0-5.0] days; P=0.02). Hospital mortality was 22.0%, and 13.3% of survivors were dialysis dependent at discharge. Independent risk factors associated with hospital mortality included older age, residence in an emerging country, use of vasopressors (emerging countries only), dialysis and mechanical ventilation, and higher APACHE score and cumulative fluid balance (developed countries only). A lower probability of renal recovery was associated with residence in an emerging country, higher APACHE score (emerging countries only) and dialysis, while mechanical ventilation was associated with renal recovery (developed countries only).

CONCLUSIONS

This study contrasts the clinical features and management of AKI and demonstrates worse outcomes in emerging than in developed countries. Differences in variations in care may explain these findings and should be considered in future trials.

Timing of acute kidney injury--does it matter? A single-centre experience from the United Kingdom

BACKGROUND

Acute kidney injury (AKI) requiring renal replacement therapy (RRT) is associated with high mortality and long-term dependence on RRT. However, there is limited information about the difference in outcome between patients who develop AKI in the community (c-AKI), and those who develop AKI in hospital (h-AKI).

AIM

Identify differences in short- and long-term outcomes between patients admitted with c-AKI and h-AKI who require intermittent haemodialysis, and to identify factors that predict poor outcome.

DESIGN & METHODS

Single-centre, retrospective analysis of 306 patients with AKI who received intermittent haemodialysis between 2009 and 2011.

FOLLOW-UP

six months. Primary endpoints: patient and renal survival. Secondary endpoints: time on dialysis, length of hospital stay, and admission to the intensive care unit (ICU).

RESULTS

Survival for patients in the h-AKI group was significantly lower, at 42.9% (compared to 72%). They had a significantly longer length of stay. However, at 6-month follow-up, the survival benefit of the c-AKI group was no longer significant. Patients with h-AKI were more likely to be dialysis independent at discharge and six months although this result did not reach statistical significance. Independent predictors of survival to discharge within the entire group included: renal/post-renal causes of AKI, younger age, pre-existing diabetes, and c-AKI. The only independent predictor for RRT dependence at discharge and six months was pre-existing chronic kidney disease.

CONCLUSIONS

h-AKI is associated with high mortality and longer hospital stays during the acute admission. However, h-AKI patients who survive are more likely to be independent of RRT at discharge and follow-up.

Acute kidney injury in China

China has a large population and bears a heavy burden of kidney diseases. Acute kidney injury (AKI) is increasingly prevalent in China and is associated with severe morbidity and mortality. The inadequacies of early diagnosis and management remain the major challenges to Chinese nephrologists. There is an urgent need for a nationwide, or even a global effort to increase an awareness of the devastating effects of AKI, to develop professional preventive strategies, as well as to achieve early diagnosis and early intervention. In this article, we review the increasing incidence of AKI and complexity behind prevention and management, focusing on differences in various clinical settings in China.

Raising awareness of acute kidney injury: a global perspective of a silent killer

Worldwide, acute kidney injury (AKI) is associated with poor patient outcomes. Over the last few years, collaborative efforts, enabled by a common definition of AKI, have provided a description of the epidemiology, natural history, and outcomes of this disease and improved our understanding of the pathophysiology. There is increased recognition that AKI is encountered in multiple settings and in all age groups, and that its course and outcomes are influenced by the severity and duration of the event. The effect of AKI on an individual patient and the resulting societal burden that ensues from the long-term effects of the disease, including development of chronic kidney disease (CKD) and end-stage renal disease (ESRD), is attracting increasing scrutiny. There is evidence of marked variation in the management of AKI, which is, to a large extent, due to a lack of awareness and an absence of standards for prevention, early recognition, and intervention. These emerging data point to an urgent need for a global effort to highlight that AKI is preventable, its course is modifiable, and its treatment can improve outcomes. In this article, we provide a framework of reference and propose specific strategies to raise awareness of AKI globally, with the goal to ultimately improve outcomes from this devastating disease.

Nephrotoxicity of alternative medicine practice

The use of alternative medicine is highly prevalent around the world; in many areas, this is so because of lack of access to, or trust in, Western medicine, and also because they are considered "natural" and therefore safe. The kidney is an organ vulnerable to toxic insults by virtue of its anatomy and function. Reports of nephrotoxicity associated with alternative medicine use encompass all forms of renal dysfunction, ranging from electrolyte abnormalities and proteinuria to acute and CKD, renal failure, and death. In countries where intensive care and dialysis support are not available, mortality is high. Mechanisms of alternative medicine-associated kidney injury include direct nephrotoxicity, which may be augmented by underlying predisposing conditions such as dehydration; contamination, or adulteration of remedies; inappropriate use or preparation of a remedy; or interactions with other medications. The use of alternative medicines is underreported to clinicians. Because many patients strongly believe in the powers of alternative medicines, it is important that alternative medicines not be demonized as a whole, but that their use and consequences be closely observed and reported to build a more comprehensive understanding of their impact in our clinical practice and to foster research on the potential harm or, in some cases, possible benefits.

Development of inpatient risk stratification models of acute kidney injury for use in electronic health records

OBJECTIVE

Patients with hospital-acquired acute kidney injury (AKI) are at risk for increased mortality and further medical complications. Evaluating these patients with a prediction tool easily implemented within an electronic health record (EHR) would identify high-risk patients prior to the development of AKI and could prevent iatrogenically induced episodes of AKI and improve clinical management.

METHODS

The authors used structured clinical data acquired from an EHR to identify patients with normal kidney function for admissions from 1 August 1999 to 31 July 2003. Using administrative, computerized provider order entry and laboratory test data, they developed a 3-level risk stratification model to predict each of 2 severity levels of in-hospital AKI as defined by RIFLE criteria. The severity levels were defined as 150% or 200% of baseline serum creatinine. Model discrimination and calibration were evaluated using 10-fold cross-validation.

RESULTS

Cross-validation of the models resulted in area under the receiver operating characteristic (AUC) curves of 0.75 (150% elevation) and 0.78 (200% elevation). Both models were adequately calibrated as measured by the Hosmer-Lemeshow goodness-of-fit test chi-squared values of 9.7 (P = 0.29) and 12.7 (P = 0.12), respectively.

CONCLUSIONS

The authors generated risk prediction models for hospital-acquired AKI using only commonly available electronic data. The models identify patients at high risk for AKI who might benefit from early intervention or increased monitoring.

Acute renal failure in hospitalized patients in China: a prospective study

Acute renal failure (ARF) is a common complication in hospitalized patients, but little is known about the epidemiology of ARF in China. In this study, we performed a prospective examination of the cause, prognosis, and risk factors associated with ARF at a hospital in Shanghai, China. We considered all ARF patients who were admitted to our hospital from December 2003 to December 2006. Among the 320 ARF patients, 135 (42.2%) were over the age of 60. Sepsis, heart failure, and nephrotoxic drug use were the leading causes of ARF. The overall mortality rate was 31.9%, and mortality rate was significantly higher among the elderly. Logistic regression indicated that heart failure, respiratory failure, and malignant cancer were risk factors independently associated with poor prognosis. In this Shanghai hospital, there was a high incidence and mortality rate of patients hospitalized with ARF. The prognosis of patients who underwent renal replacement therapy was better than those who were treated more conservatively.

Acute kidney injury in the elderly population

The elderly population is more prone to acute kidney injury (AKI) than younger populations. Older patients have less renal reserve because of reduced glomerular filtration rates due to anatomic/functional changes, and concomitant diseases such as hypertension, diabetes, atherosclerosis, heart failure, ischemic renal disease, and obstructive uropathy. The risk of AKI may also increase as a result of aggressive diagnostic and therapeutic procedures, which include medical agents, radiology, and surgical intervention. AKI in the elderly has a multifactorial physiopathology due to different etiologies. Studies that have specifically compared prognosis of AKI in elderly versus young over the recent years suggest that age is a predictor of long-term outcome. In most cases, the treatment of AKI is similar for all age groups. The majority of critically ill patients with AKI will eventually need renal replacement therapy (RRT). The influence of RRT on renal outcome remains a subject of intense investigation and debate. Avoiding situations that could damage the kidney is an important strategy to prevent AKI development in the elderly, besides medical and interventional therapeutics.

Acute kidney injury predicts outcomes of non-critically ill patients

OBJECTIVE

To evaluate whether acute kidney injury (AKI), defined as an increase in the serum creatinine level of 0.3 mg/dL or more within 48 hours, predicts outcomes of non-critically ill patients.

PATIENTS AND METHODS

Among the adults admitted from June 1, 2005, to June 30, 2007, to the medical wards of a community teaching hospital, 735 patients with AKI and 5089 controls were identified. Demographic and health information, serum creatinine values, and outcomes were abstracted from patients' computerized medical records. Outcomes of patients with AKI were compared with those of controls. In an additional case-control analysis, more detailed clinical information was abstracted from the medical records of 282 pairs of randomly selected, age-matched AKI cases and controls. Conditional multivariate logistic regression analyses were used to adjust for potential confounders of AKI effect on outcomes.

RESULTS

Overall, patients with AKI had higher in-hospital mortality (14.8% vs 1.5%; P<.001), longer lengths of stay (median 7.9 vs 3.7 days; P<.001), and higher rates of transfer to critical care areas (28.6% vs 4.3%; P<.001); survivors were more likely to be discharged to an extended care facility (43.1% vs 20.3%; P<.001). Conditional multivariate logistic regression analyses of the 282 pairs of cases and controls showed that patients with AKI were 8 times more likely to die in hospital (odds ratio [OR], 7.9; 95% CI [confidence interval], 2.9-15.3) and were 5 times more likely to have prolonged (>or=7 days) hospital stays (OR, 5.2; 95% CI, 3.5-7.9) and require intensive care (OR, 4.7; 95% CI, 2.7-8.1), after adjustment for age, comorbidities, and other potential confounders.

CONCLUSION

In this study, AKI was associated with adverse outcomes in non-critically ill patients.

Rapid reversal of acute kidney injury and hospital outcomes: a retrospective cohort study

BACKGROUND

Acute kidney injury (AKI), defined as an increment in serum creatinine level of 0.3 mg/dL or greater in 48 hours, is associated with poor outcomes. The prognosis associated with an increased creatinine level, either on admission or that develops in the hospital (ie, AKI), that rapidly returns to normal is not known.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

6,033 patients admitted to medical wards of a community teaching hospital between 2005 and 2007.

PREDICTOR

AKI was defined as an increase in serum creatinine level of 0.3 mg/dL or greater within 48 hours. Increased serum creatinine level on admission was defined as serum creatinine greater than1.2 mg/dL on hospital admission in patients who did not subsequently meet criteria for AKI. Patients with a serum creatinine level of 1.2 mg/dL or less who had no increase of 0.3 mg/dL or greater within 48 hours during their hospital stay served as controls.

OUTCOMES & MEASUREMENTS

Mortality, length of stay, intensive care unit transfer, and discharge destination were outcomes of interest.

RESULTS

Of 6,033 patients, 735 had AKI. Of these, 443 (60%) had serum creatinine levels that subsequently decreased by 0.3 mg/dL or greater within 48 hours and 197 returned to normal levels within 48 hours. Overall, patients with AKI had significantly greater mortality rates (14.8%) than patients without AKI with increased serum creatinine levels on admission (2.5%) and controls (1.3%; P < 0.001). Patients with AKI with a serum creatinine level that returned to normal within 48 hours had substantially greater mortality rates (14.2%) than those who initially presented with an increased serum creatinine level on admission and subsequent serum creatinine level decrease of 0.3 mg/dL or greater to normal within 48 hours (2.5%; P < 0.01).

LIMITATIONS

Sample sizes of subgroups were small. Causes of AKI and increases in serum creatinine levels on admission were not assessed.

CONCLUSIONS

An increase in serum creatinine level of 0.3 mg/dL or greater during 48 hours of hospitalization predicts outcomes even if the value returns to normal. Patients who present to the hospital with an increased creatinine level that returns rapidly to normal have outcomes approaching those with serum creatinine levels consistently in the normal range.

Community-acquired acute kidney injury in Asia

Asia, the largest continent in the world, is heterogeneous in the ethnic, socioeconomic, and developmental status of its populations. A vast majority of it is poor with no adequate access to modern health care, making an accurate estimation of the nature and extent of acute kidney injury (AKI) difficult. Community-acquired AKI in otherwise healthy individuals is common, and the population developing AKI is younger compared with its counterparts in Europe or North America. The etiologic spectrum varies in different geographic regions of Asia depending on environmental, cultural, and socioeconomic factors. Some of the etiologic factors include AKI in relation to infectious diseases, intravascular hemolysis caused by glucose 6-phosphate dehydrogenase deficiency, poisonings caused by industrial chemicals or copper sulphate, animal venoms, natural medicines, heat stroke, and after complications of pregnancy. Preventive opportunities are missed because of failure to recognize the risk factors and early signs of AKI. Patients often present late for treatment, leading to multi-organ involvement and increased mortality. The exact etiologic diagnosis cannot be established in many instances because of a lack of appropriate laboratory support. Modern methods of renal replacement therapy are not universally available; and intermittent peritoneal dialysis is still widely practiced in many areas.

Acute kidney injury associated with the use of traditional medicines

The use of traditional medicine is common worldwide, with rates of use of over 80% in some populations. Considering the large number of people using traditional remedies throughout the world, it does seem that most do so without major adverse effects. Nevertheless, many folk medicines can cause kidney injury. Drug-induced nephrotoxicity reportedly contributes to up to 26% of cases of hospital-acquired acute kidney injury (AKI) and 18% of cases of community-acquired AKI globally, and folk remedies account for up to 35% of cases of AKI in the developing world. The kidney is highly susceptible to toxic insults because its intrinsic functions expose it to exceptionally high concentrations of any particular toxic substance. Clinical syndromes of nephrotoxicity can be defined according to the predominant regions of the kidney affected by the toxin, and reversibility of the injury is likely related to the severity and nature of the injury and also to the duration of toxin exposure. In countries with well-developed health-care systems, a large proportion of patients with nephrotoxicity will recover at least some renal function with adequate supportive care and dialysis. Health-care practitioners in all countries should be aware of the high prevalence of the use of alternative therapies and should be proactive in obtaining this information from patients. In poorer countries, where large proportions of the population rely on traditional medicine, attempts should be made to integrate traditional healers into the health-care system.

The contrasting characteristics of acute kidney injury in developed and developing countries

Acute kidney injury (AKI) has become increasingly prevalent in both developed and developing countries, and is associated with severe morbidity and mortality, especially in children. Uncertainty regarding the true incidence of AKI limits awareness of the problem, thereby reducing political visibility of the disorder and hampering efforts to prevent its occurrence. In developed countries, AKI occurs predominantly in urban intensive care units and is associated with multiorgan failure and sepsis, high mortality, and occurrence in older populations. While cases of AKI in urban areas of the developing world have similar characteristics to those in the developed world, AKI in rural regions commonly develops in response to a single disease and specific conditions (e.g. gastroenteritis) or infections (e.g. severe malaria, leptospirosis, or hemolytic-uremic syndrome) and in younger otherwise healthy individuals. Many causes of AKI in rural settings, such as diarrhea, poisoning, malaria, or septic abortion, can be prevented by interventions at the individual, community, and regional levels. Treatment with dialysis is often unavailable or too costly in developing regions, so there must be community-wide efforts to eradicate causes of AKI, expedite diagnosis, and aggressively manage prerenal conditions and specific infections. We have reviewed recent literature on AKI, identified differences and similarities in the condition between developed and developing areas, analyzed the practical implications of the identified differences, and made evidence-based recommendations for study and management.