Neutrophil Gelatinase-Associated Lipocalin for Assessment of Acute Kidney Injury in Cirrhosis: A Prospective Study

Practice patterns and outcomes associated with intravenous albumin in patients with cirrhosis and acute kidney injury

BACKGROUND & AIMS

Guidelines recommend albumin as the plasma-expander of choice for acute kidney injury (AKI) in cirrhosis. However, the impact of these recommendations on patient outcomes remains unclear. We aimed to determine the practice-patterns and outcomes associated with albumin use in a large, nationwide-US cohort of hospitalized cirrhotics with AKI.

METHODS

A retrospective cohort study was performed in hospitalized cirrhotics with AKI using Cerner-Health-Facts database from January 2009 to March 2018. 6786 were included for analysis on albumin-practice-patterns, and 4126 had available outcomes data. Propensity-score-adjusted model was used to determine the association between albumin use, AKI-recovery and in-hospital survival.

RESULTS

Median age was 61-years (60% male, 70% white), median serum-creatinine was 1.8 mg/dL and median Model for End-stage Liver Disease Sodium (MELD-Na) score was 24. Albumin was given to 35% of patients, of which 50% received albumin within 48-hours of AKI-onset, and 17% received appropriate weight-based dosing. Albumin was used more frequently in patients with advanced complications of cirrhosis, higher MELD-Na scores and patients admitted to urban-teaching hospitals. After propensity-matching and multivariable adjustment, albumin use was not associated with AKI-recovery (odds ratio [OR] 0.70, 95% confidence-interval [CI]: 0.59-1.07, P = .130) or in-hospital survival (OR 0.76 [95% CI: 0.46-1.25], P = .280), compared with crystalloids. Findings were unchanged in subgroup analyses of patients with varying cirrhosis complications and disease severity.

CONCLUSIONS

USA hospitalized patients with cirrhosis and AKI frequently do not receive intravenous albumin, and albumin use was not associated with improved clinical outcomes. Prospective randomised trials are direly needed to evaluate the impact of albumin in cirrhotics with AKI.

Hepatorenal syndrome in acute-on-chronic liver failure with acute kidney injury: more questions requiring discussion

In cirrhosis with ascites, hepatorenal syndrome (HRS) is a specific prerenal dysfunction unresponsive to fluid volume expansion. Acute-on-chronic liver failure (ACLF) comprises a group of clinical syndromes with multiple organ failure and early high mortality. There are differences in the characterization of ACLF between the Eastern and Western medical communities. Patients with ACLF and acute kidney injury (AKI) have more structural injuries, contributing to confusion in diagnosing HRS-AKI. In this review, we discuss progress in the pathogenesis, diagnosis, and management of HRS-AKI, especially in patients with ACLF. Controversy regarding HRS-AKI in ACLF and acute liver failure, hepatic carcinoma, shock, sepsis, and chronic kidney disease is also discussed. Research on the treatment of HRS-AKI with ACLF needs to be more actively pursued to improve disease prognosis.

Value of shear wave elastography in predicting hepatorenal syndrome in patients with liver cirrhosis and ascites

BACKGROUND

Early detection of renal damage in cirrhosis is critical to prevent hepatorenal syndrome (HRS). Although shear wave elastography (SWE) is useful for the assessment of kidney stiffness, no study has yet investigated the clinical feasibility of SWE for predicting HRS.

OBJECTIVE

The aim of this study was to evaluate the value of SWE in predicting HRS in patients with cirrhosis and ascites.

METHODS

A total of 131 patients with liver cirrhosis and ascites were recruited and followed them for 30 days for the development of AKI. Ultrasonographic examination was performed on all patients at hospital admission. The baseline clinical characteristics, renal biomarkers, renal resistive index (RI) and Young's modulus (YM) were recorded, and their relationship with development HRS was investigated.

RESULTS

Sixty-eight patients developed AKI, 23 of them were HRS. Compared with patients in the non-AKI group and non-HRS group, the values of serum cystatin C (CystC), urine neutrophil gelatinase-associated lipocalin (NGAL) and renal RI were significantly increased, while the YM value was significantly decreased in the AKI group and HRS group. Correlation analysis showed that YM was significantly and negatively associated with serum creatinine, serum CystC, urinary NGAL and renal RI in addition to the significant association with the AKI stage. Logistic regression and ROC analysis showed that urine NGAL, renal RI and YM were closely related to the development of HRS. Among them, YM had a good predictive ability in predicting the occurrence of HRS, and the predictive value (AUC = 0.894) was improved when combined with renal RI.

CONCLUSION

SWE can indicate renal injury in patients with cirrhosis and ascites. The combination of YM and RI has a good predictive value for the occurrence of HRS.

Sequential changes in urinary biomarker levels in patients with cirrhosis and severe hepatorenal syndrome

Whether tubular injury develops in patients with acute kidney injury owing to hepatorenal syndrome (AKI-HRS) is controversial. We performed repeated measurements of biomarkers of tubular injury during a 14-day period in 60 patients with cirrhosis and AKI (34 with AKI-HRS meeting the classical definition of type 1 HRS and 26 with AKI owing to acute tubular necrosis, AKI-ATN). Nineteen of 34 patients had resolution of AKI-HRS, while the remainder had persistent AKI-HRS. The persistence of AKI-HRS was associated with remarkably high short-term mortality. There were no significant differences in urinary NGAL or IL-18 between patients with resolution vs those with persistent AKI-HRS throughout the 14-day period. By contrast, biomarker levels were significantly lower in AKI-HRS, even if persistent, compared to AKI-ATN. These findings are highly suggestive of lack of significant tubular injury in AKI-HRS and could be of value in the clinical decision between combined liver-kidney or liver transplantation alone in patients with cirrhosis and AKI candidates to transplantation.

Urinary neutrophil gelatinase-associated lipocalin: Acute kidney injury in liver cirrhosis

Acute kidney injury (AKI) in liver cirrhosis is associated with poor clinical outcomes including an increased long and short-term mortality. The common type of AKI observed in patients with cirrhosis are prerenal AKI (PRA), hepatorenal syndrome (HRS) and acute tubular necrosis (ATN). Despite the growing knowledge and uniform definition for the diagnosis of AKI, there are several challenges including, early diagnosis and management. Precisely differentiating the type of AKI is critical, as therapies differ significantly. In this review, we summarize AKI in liver cirrhosis, their definition, pathophysiology and deficiencies of using the existing biomarker, serum creatinine. We outline the current clinical evidence on the novel biomarker urinary neutrophil gelatinase-associated lipocalin (uNGAL) and its potential role as a biomarker in the early detection, differentiation and prognostication of AKI. This review also briefly talks about other forthcoming biomarkers which hold promise in the management of AKI in liver cirrhosis.

Early kidney injury in immunoglobulin A vasculitis: Role of renal biomarkers

BACKGROUND

We aimed to determine whether urine kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) can be used as early noninvasive biomarkers of kidney injury in immunoglobulin A vasculitis.

METHODS

Patients who were diagnosed with immunoglobulin A vasculitis were included in the study. Urine samples were collected for determination of urine KIM-1 and NGAL levels. The control group consisted of age-matched healthy children.

RESULTS

Sixty-one patients who were diagnosed with immunoglobulin A vasculitis were included in the study; 37.7% of these patients were determined to have renal involvement. Median KIM-1 was found to be significantly higher in the patient group (69.59 pg/mL) than the control group (40.84 pg/mL) (P = 0.001). Median NGAL was determined to be statistically significantly higher in the patient group (59.87 ng/mL) compared with the control group (44.87 ng/mL) (P = 0.013). In 23.6% of the patients without renal involvement at admission renal involvement developed within the following 6 months. When median KIM-1 and NGAL at admission of these patients were compared with the control group, they were determined to be statistically significantly higher (P = 0.001, P = 0.003).

CONCLUSIONS

The fact that our patients with late-term nephropathy had no hematuria and / or proteinuria and that KIM-1 and NGAL levels were determined to be high indicates that these biomarkers might be potentially reliable, noninvasive and early determinants of kidney injury.

The Role of Urinary N-Acetyl-β-d-glucosaminidase in Cirrhotic Patients with Acute Kidney Injury: Multicenter, Prospective Cohort Study

Background and Aims: Currently, it is difficult to predict the reversibility of renal function and to discriminate renal parenchymal injury in cirrhotic patients with acute kidney injury (AKI). The aim of this study is to evaluate whether urine N-acetyl-β-d-Glucosaminidase (NAG) can predict the survival and response to terlipressin in cirrhotic patients with AKI. Methods: Two hundred sixty-two cirrhotic consecutive patients who developed AKI were prospectively enrolled from 11 tertiary medical centers in Korea between 2016 to 2019. AKI was defined as an increase in serum Cr (SCr) of 0.3 mg/dL or a 50% increase in baseline SCr. Patients diagnosed with hepatorenal syndrome (HRS-AKI) were treated with terlipressin plus albumin. Results: The patients were 58.8 ± 12.9 years old on average and were predominantly male (72.5%). The mean MELD score was 25.3 ± 9.1. When classified according to the AKI phenotype, there were 119 pre-renal, 52 acute tubular necrosis, 18 miscellaneous, and 73 HRS-AKI patients. However, the urine NAG was not effective at discriminating AKI phenotypes, except for HRS-AKI. The baseline urine NAG increased as the baseline AKI stage increased (p < 0.001). In addition, within the same AKI stage, the urine NAG values were significantly lower in the AKI-resolved group than in the unresolved group. The urine NAG level was significantly lower in living patients compared with those who died or who underwent a liver transplant within 3 months (p = 0.005). In the multivariate analysis, the increased urine NAG was a significant risk factor for the 3-month transplant-free survival (TFS) rate, especially in patients with Child–Pugh class ≤ B or MELD < 24. The urine NAG did not predict the response to terlipressin treatment in patients with HRS. Conclusions: Urine NAG is strongly associated with the severity of AKI in patients with liver cirrhosis and is useful for predicting the 3-month TFS.

Clinical Implementation and Initial Experience of Neutrophil Gelatinase-Associated Lipocalin Testing for the Diagnostic and Prognostic Assessment of Acute Kidney Injury Events in Hospitalized Patients

INTRODUCTION

The use of novel kidney injury biomarkers has been shown to improve diagnostic assessment and prognostic prediction in various populations with acute kidney injury (AKI), but their use in a standard clinical practice have been rarely reported.

METHODS

We reported the clinical implementation of neutrophil gelatinase-associated lipocalin (NGAL) measurement for routine AKI diagnostic workup of patients receiving nephrology consultation in a tertiary academic centre. Specific focus was made on the diagnostic performance to discriminate functional ("pre-renal") from intra-renal AKI and to predict AKI progression.

RESULTS

Forty-five urine NGAL (uNGAL) and 25 plasma NGAL (pNGAL) samples in the first 50 consecutive patients were analysed. KDIGO Stage 1, 2, 3 AKI, and renal replacement therapy occurred in 10%, 40%, 50%, and 24% of cases, respectively. The uNGAL was lower in patients with transient AKI (<48 h) and no sign of urinary tract infections (37 [25-167] ng/mL) than sustained or progressive AKI (298 [74-1,308] ng/mL) (p = 0.016), while pNGAL did not discriminate transient (264 [100-373] ng/mL) from persistent AKI (415 [220-816] ng/mL) (p = 0.137). The median uNGAL level was 63 (35-1,123) ng/mL for functional/pre-renal AKI and 451 (177-1,315) ng/mL for intra-renal AKI (p = 0.043), while the pNGAL was 264 (114-468) and 415 (230-816) ng/mL (p = 0.235), respectively.

CONCLUSION

NGAL, as part of the routine workup, is useful for diagnostic and prognostic assessment of new-onset AKI in clinical practice. Interpretation of an increased NGAL level should be clinically evaluated in its clinical context, particularly considering concomitant infection (urinary or systemic). Clinical adoption of emerging AKI biomarkers as diagnostic tests in clinical practice should be further encouraged.

Current knowledge about biomarkers of acute kidney injury in liver cirrhosis

Acute kidney injury (AKI) is common in advanced cirrhosis. Prerenal azotemia, hepatorenal syndrome, and acute tubular necrosis are the main causes of AKI in patients with cirrhosis. Evaluation of renal function and differentiation between functional and structural kidney injury are important issues in the management of cirrhosis. However, AKI in cirrhosis exists as a complex clinical spectrum rather than concrete clinical entity. Based on current evidence, changes in serum creatinine (Cr) levels remain the most appropriate standard for defining AKI in cirrhosis. However, serum Cr has a limited role in assessing renal function in this population. This review examines previous studies that investigated the ability of recent biomarkers for AKI in cirrhosis from the perspective of earlier and accurate diagnosis, classification of AKI phenotype, and prediction of clinical outcomes. Serum cystatin C and urine neutrophil gelatinase-associated lipocalin have been extensively studied in cirrhosis, and have facilitated improved diagnosis and prognosis prediction in patients with AKI. In addition, urine N-acetyl-β-D-glucosaminidase, interleukin 18, and kidney injury molecule 1 are other promising biomarkers for advanced cirrhosis. However, the clinical significance of these markers remains unclear because there are no cut-off values defining the normal range and differentiating phenotypes of AKI. In addition, AKI has been defined in terms of serum Cr, and renal biopsy-the gold standard-has not been carried out in most studies. Further discovery of innovate biomarkers and incorporation of various markers could improve the diagnosis and prognosis prediction of AKI, and will translate into meaningful improvements in patient outcomes.

Acute kidney injury and hepatorenal syndrome in cirrhosis

Acute kidney injury (AKI) in cirrhosis, including hepatorenal syndrome (HRS), is a common and serious complication in cirrhotic patients, leading to significant morbidity and mortality. AKI is separated into two categories, non-HRS AKI and HRS-AKI. The most recent definition and diagnostic criteria of AKI in cirrhosis and HRS have helped diagnose and prognosticate the disease. The pathophysiology behind non-HRS-AKI and HRS is more complicated than once theorized and involves more processes than just splanchnic vasodilation. The common biomarkers clinicians use to assess kidney injury have significant limitations in cirrhosis patients; novel biomarkers being studied have shown promise but require further studies in clinical settings and animal models. The overall management of non-HRS AKI and HRS-AKI requires a systematic approach. Although pharmacological treatments have shown mortality benefit, the ideal HRS treatment option is liver transplantation with or without simultaneous kidney transplantation. Further research is required to optimize pharmacologic and nonpharmacologic approaches to treatment. This article reviews the current guidelines and recommendations of AKI in cirrhosis.

Recent advances in the understanding and management of hepatorenal syndrome

Renal dysfunction occurs frequently in hospitalized patients with advanced chronic liver disease (ACLD)/cirrhosis and has profound prognostic implications. In ACLD patients with ascites, hepatorenal syndrome (HRS) may result from circulatory dysfunction that leads to reduced kidney perfusion and glomerular filtration rate (in the absence of structural kidney damage). The traditional subclassification of HRS has recently been replaced by acute kidney injury (AKI) type of HRS (HRS-AKI) and non-AKI type of HRS (HRS-NAKI), replacing the terms “HRS type 1” and “HRS type 2”, respectively. Importantly, the concept of absolute serum creatinine (sCr) cutoffs for diagnosing HRS was partly abandoned and short term sCr dynamics now may suffice for AKI diagnosis, which facilitates early treatment initiation that may prevent the progression to HRS-AKI or increase the chances of AKI/HRS-AKI reversal. Recent randomized controlled trials have established (a) the efficacy of (long-term) albumin in the prevention of complications of ascites (including HRS-AKI), (b) the benefits of transjugular intrahepatic portosystemic shunt placement in patients with recurrent ascites, and (c) the superiority of terlipressin over noradrenaline for the treatment of HRS-AKI in the context of acute-on-chronic liver failure. This review article aims to summarize recent advances in the understanding and management of HRS.

End-stage liver disease: Management of hepatorenal syndrome

Hepatorenal syndrome (HRS) is a serious complication of cirrhosis with high morbidity and mortality rates. Recently, the definition of HRS type 1 has been updated and is now called HRS-AKI. This new definition reduces the risk of delaying HRS treatment and eliminates the need to establish a minimum creatinine cut-off for the diagnosis of HRS-AKI. From a pathophysiological point of view, newly identified mechanisms involved in the development of HRS are related to the inflammatory response, conditioning the development of extrahepatic organ dysfunction in patients with cirrhosis. One of the main challenges for the diagnosis of HRS is the validation of new biomarkers to obtain an early and differential diagnosis of kidney injury (eg HRS vs. ATN). Treatment of HRS is based on the use of vasoconstrictive agents in combination with albumin and terlipressin is the most widely used vasoconstrictor drug, with a high response rate. The effects of a continuous infusion of terlipressin at a dose of 2-12 mg/day was similar to bolus administration, but with lower rates of adverse events. Finally, MELD/MELD-Na which includes creatinine as one of its main determinants gives AKI-HRS patients priority on the waiting list (WL) for liver transplant (LT). However, the MELD and MELD-Na scores are reduced in responding patients, resulting a longer waiting time in these patients than in non-responders. Thus, the initial MELD/MELD-Na score (pre-treatment value) should be used to prioritize patients on the WL for LT in these cases.

Global strategy for the diagnosis and management of acute kidney injury in patients with liver cirrhosis

Acute kidney injury (AKI) is a clinical syndrome that complicates the course and worsens clinical outcomes in patients with chronic liver diseases. It is a common complication in hospitalised patients with liver cirrhosis, especially those with decompensated cirrhosis, associated with a high mortality rate. Considering its impact on patient prognosis, efforts should be made to diagnose and tailor therapeutic interventions for AKI at an early stage. In the past decade, a significant progress has been made to understand the key events and define major prognostic factors for the onset and progression of AKI in the cirrhotic population leading hepatologists to redefine the classic definition of hepatorenal syndrome and renal failure in this specific population.

Impact of acute kidney injury on prognosis and the effect of tolvaptan in patients with hepatic ascites

BACKGROUND

In hepatic cirrhosis, ascites and acute kidney injury (AKI) portend poor prognosis. We examined the incidence and characteristics of AKI in patients with hepatic ascites and the impact of diuretics on AKI onset.

METHODS

This study included 337 patients with hepatic ascites treated with oral diuretics during September 2013-June 2019. Incidence of AKI, cumulative survival by AKI status, and prognostic factors were investigated. Patients were divided into those treated with tolvaptan (TLV) [TLV group (n = 244)] and those not treated with TLV [control group (n = 93)]. After propensity score matching, the incidence of AKI and changes in renal function and doses of diuretics were compared.

RESULTS

The incidence of AKI overall was 35% (n = 118). Patients with AKI had a significantly worse survival than those without AKI (P = 0.001), indicating that AKI is an independent prognostic factor for hepatic ascites (P = 0.025). After adjustment for background factors in the two groups (n = 77 each), the TLV group had a significantly lower incidence of AKI (27.6% vs. 44.7%, P = 0.028). While renal function worsened with higher natriuretic agent doses in the control group, no significant change was observed in the TLV group, suggesting that TLV is an independent prognostic factor for AKI onset.

CONCLUSIONS

Our study suggests that concomitant AKI significantly worsens survival in Japanese patients with hepatic ascites, and TLV and natriuretic agent combination therapy might lead to an excellent synergistic therapeutic effect of hepatic ascites and inhibition of AKI onset.

Effectiveness of Plasma and Urine Neutrophil Gelatinase-Associated Lipocalin for Predicting Acute Kidney Injury in High-Risk Patients

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a useful biomarker for acute kidney injury (AKI) prediction. However, studies on whether using both plasma NGAL (PNGAL) and urine NGAL (UNGAL) can improve AKI prediction are limited. We investigated the best approach to predict AKI in high-risk patients when using PNGAL and UNGAL together.

METHODS

We enrolled 151 AKI suspected patients with one or more AKI risk factors. We assessed the diagnostic performance of PNGAL and UNGAL for predicting AKI according to chronic kidney disease (CKD) status by determining the areas under the receiver operating curve (AuROC). Independent predictors of AKI were assessed using univariate and multivariate logistic regression analyses.

RESULTS

In the multivariate logistic regression analysis for all patients (N=151), Model 2 and 3, including PNGAL (P=0.012) with initial serum creatinine (S-Cr), showed a better AKI prediction power (R2=0.435, both) than Model 0, including S-Cr only (R2=0.390). In the non-CKD group (N=135), the AuROC of PNGAL for AKI prediction was larger than that of UNGAL (0.79 vs 0.66, P=0.010), whereas in the CKD group (N=16), the opposite was true (0.94 vs 0.76, P=0.049).

CONCLUSIONS

PNGAL may serve as a useful biomarker for AKI prediction in high-risk patients. However, UNGAL predicted AKI better than PNGAL in CKD patients. Our findings provide guidance for selecting appropriate specimens for NGAL testing according to the presence of CKD in AKI high-risk patients.

Prognosis predictability of serum and urine renal markers in patients with decompensated cirrhosis: A multicentre prospective study

BACKGROUND AND AIMS

This prospective observational study aimed to evaluate the best serum and urine markers to assess predictability for the prognosis of patients with decompensated cirrhosis.

METHODS

Serum creatinine and cystatin C (CysC), and urinary N-acetyl-beta-D glucosaminidase (uNAG) and neutrophil gelatinase-associated lipocalin (uNGAL) levels were measured from hospitalized patients with decompensated cirrhosis.

RESULTS

In total, 328 patients (mean age, 57.2 ± 12.0 years; 237 men) with decompensated cirrhosis were included. Alcoholic liver disease was the most frequent underlying liver disease (68.0%). Acute kidney injury (AKI) was concomitantly present in 41 patients (12.5%) at baseline. INR, serum creatinine and CysC levels, and uNAG and uNGAL levels were significantly higher in patients with AKI. During hospitalization, AKI had progressed in 37 patients (11.3%). In 287 patients without AKI, the incidence of AKI at 3, 6, 9 and 12 months was 15.4%, 22.2%, 28.6% and 32.5% respectively. On multivariate analysis, serum CysC and uNAG levels were independent predictors of AKI, and their optimal cut-off values were 1.055 mg/L and 23.1 U/g urinary Cr respectively. When patients were classified into three groups with these cut-off values of serum CysC and uNAG levels (group 1, both low; group 2, one of two high; and group 3, both high), progression of AKI during hospitalization (P = .001), incidence of AKI in patients without AKI at baseline (P = .001) and mortality rate (P < .001) differed significantly according to serum CysC and uNAG levels.

CONCLUSION

Serum CysC and uNAG levels are useful prognostic markers for renal outcomes and mortality in patients with decompensated cirrhosis.

Hepatorenal syndrome: pathophysiology, diagnosis, and management

Hepatorenal syndrome (HRS), the extreme manifestation of renal impairment in patients with cirrhosis, is characterized by reduction in renal blood flow and glomerular filtration rate. Hepatorenal syndrome is diagnosed when kidney function is reduced but evidence of intrinsic kidney disease, such as hematuria, proteinuria, or abnormal kidney ultrasonography, is absent. Unlike other causes of acute kidney injury (AKI), hepatorenal syndrome results from functional changes in the renal circulation and is potentially reversible with liver transplantation or vasoconstrictor drugs. Two forms of hepatorenal syndrome are recognized depending on the acuity and progression of kidney injury. The first represents an acute impairment of kidney function, HRS-AKI, whereas the second represents a more chronic kidney dysfunction, HRS-CKD (chronic kidney disease). In this review, we provide critical insight into the definition, pathophysiology, diagnosis, and management of hepatorenal syndrome.

Management of Hepatorenal Syndrome: A Review

Acute kidney injury (AKI) occurs frequently in patients with cirrhosis, and hepatorenal syndrome (HRS) is second most common etiology of AKI after volume responsible pre-renal etiology. AKI in these patients negatively impacts pre- and post-transplant patient survival and healthcare burden. Reduced effective blood volume with consequent reduced renal blood flow, along with systemic inflammation in patients with decompensated cirrhosis, result in susceptibility to HRS. In this article, we will review updates over the last 5 years on the changing definition with diagnostic criteria and nomenclature of AKI and HRS, data on medical treatment with vasoconstrictors, and urinary biomarkers in diagnosis of etiology of AKI. We will also discuss the significance of liver transplantation evaluation once the diagnosis of HRS is established and the post-transplant immunosuppression management. We will also review one of the challenging issues that remains among transplant-eligible patients, that of allocation of simultaneous liver kidney transplant. Finally, we will review the new implemented policy from the Organ Procurement Transplant Network on simultaneous liver kidney allocation.

Urine Neutrophil Gelatinase-associated Lipocalin (NGAL) for Prediction of Persistent AKI and Major Adverse Kidney Events

We aimed to determine whether urinary neutrophil gelatinase-associated lipocalin (uNGAL) can accurately predict persistent AKI, major adverse kidney events at 30 days (MAKE30) and 365 days (MAKE365) in hospitalized AKI patients. This is a retrospective study of adult patients who were admitted at King Chulalongkorn Memorial Hospital. We performed multivariable logistic regression for persistent AKI, MAKE30, and MAKE365. We developed equations for predicting MAKE30 and MAKE365 and divided the dataset into derivation and validation cohorts. uNGAL performance and predictive models were assessed using the area under the receiver operating characteristic curve (AROC). Among 1,322 patients with AKI, 76.9%, 45.1%, and 61.7% had persistent AKI, MAKE30, and MAKE365. The AROC were 0.75 (95% confidence interval[CI] 0.70–0.80), 0.66 (95%CI 0.61–0.71), and 0.64 (95%CI 0.59–0.70) for prediction of persistent AKI, MAKE30, and MAKE365 by uNGAL. The AROC in the validation dataset combining uNGAL with clinical covariates were 0.74 (95%CI 0.69–0.79) and 0.72 (95%CI 0.67–0.77) for MAKE30 and MAKE365. We demonstrated an association between uNGAL and persistent AKI, MAKE30, and MAKE365. Prediction models combining uNGAL can modestly predict MAKE30 and MAKE365. Therefore, uNGAL is a useful tool for improving AKI risk stratification.

The value of ascitic neutrophil gelatinase-associated lipocalin in decompensated liver cirrhosis with spontaneous bacterial peritonitis

Background

Spontaneous bacterial peritonitis (SBP) is one of the most critical complications of decompensated liver cirrhosis. This study aimed to assess whether ascitic neutrophil gelatinase‐associated lipocalin (NGAL), a reliable inflammation biomarker, can be used to detect SBP in decompensated cirrhosis patients and to predict mortality from decompensated cirrhosis‐related SBP.

Methods

This study included 204 hospitalized patients with ascites of decompensated liver cirrhosis and follow‐up of 28 days. We measured ascitic NGAL levels by the latex‐enhanced immunoturbidimetric method. Simultaneously, we observed the patterns of ascitic NGAL levels in the SBP group after 7 days of anti‐infection treatment with third‐generation cephalosporins.

Results

The ascitic NGAL levels significantly increased in the SBP group compared with that in the non‐SBP group, 111(83.9, 178) ng/mL vs 48(35.4, 63) ng/mL, P < .001. Likewise, the ascitic NGAL levels of SBP were higher than non‐SBP with or without renal dysfunction. There was a positive relationship between ascitic NGAL and ascitic polymorphonuclear (PMN) leukocyte and a negative relationship between ascitic NGAL and ascitic albumin in the SBP group. An ascitic NGAL cutoff of 108.95 ng/mL was used for predicting a poor prognosis for SBP patients. Ascitic NGAL and the model for end‐stage liver disease score were independent risk factors in decompensated liver cirrhosis patients with SBP through multivariate Cox regression. A dynamic trend of ascitic NGAL in SBP patients was consistent with the clinical prognosis.

Conclusion

Ascitic NGAL may not only be a biomarker for monitoring SBP but also a predictor for more severe outcomes in decompensated cirrhosis‐related SBP.

Reappraising the spectrum of AKI and hepatorenal syndrome in patients with cirrhosis

The occurrence of acute kidney injury (AKI) in patients with end-stage liver disease constitutes one of the most challenging clinical scenarios in in-hospital and critical care medicine. Hepatorenal syndrome type 1 (HRS-1), which is a specific type of AKI that occurs in the context of advanced cirrhosis and portal hypertension, is associated with particularly high mortality. The pathogenesis of HRS-1 is largely viewed as a functional derangement that ultimately affects renal vasculature tone. However, new insights suggest that non-haemodynamic tubulo-toxic factors, such as endotoxins and bile acids, might mediate parenchymal renal injury in patients with cirrhosis, suggesting that concurrent mechanisms, including those traditionally associated with HRS-1 and non-traditional factors, might contribute to the development of AKI in patients with cirrhosis. Moreover, histological evidence of morphological abnormalities in the kidneys of patients with cirrhosis and renal dysfunction has prompted the functional nature of HRS-1 to be re-examined. From a clinical perspective, a diagnosis of HRS-1 guides utilization of vasoconstrictive therapy and decisions regarding renal replacement therapy. Patients with cirrhosis are at risk of AKI owing to a wide range of factors. However, the tools currently available to ascertain the diagnosis of HRS-1 and guide therapy are suboptimal. Short of liver transplantation, goal-directed haemodynamically targeted pharmacotherapy remains the cornerstone of treatment for this condition; improved understanding of the underlying pathogenic mechanisms might lead to better clinical outcomes. Here, we examine our current understanding of the pathophysiology of HRS-1 and existing challenges in its diagnosis and treatment.

News in pathophysiology, definition and classification of hepatorenal syndrome: A step beyond the International Club of Ascites (ICA) consensus document

Renal dysfunction is a common, life-threatening complication occurring in patients with liver disease. Hepatorenal syndrome (HRS) has been defined as a purely "functional" type of renal failure that often occurs in patients with cirrhosis in the setting of marked abnormalities in arterial circulation, as well as overactivity of the endogenous vasoactive systems.^4,5 In 2007, the International Club of Ascites (ICA) classified HRS into types 1 and 2 (HRS-1 and HRS-2).⁵ HRS-1 is characterised by a rapid deterioration of renal function that often occurs because of a precipitating event, while HRS-2 is a moderate and stable or slowly progressive renal dysfunction that often occurs without an obvious precipitant. Clinically, HRS-1 is characterised by acute renal failure while HRS-2 is mainly characterised by refractory ascites. Nevertheless, after these two entities were first described, new concepts, definitions, and diagnostic criteria have been developed by nephrologists for renal dysfunction in the general population and hospitalised patients. In particular, the definitions and characterisation of acute kidney injury (AKI), acute kidney disease and chronic kidney disease have been introduced/refined.⁶ Accordingly, a debate among hepatologists of the ICA led to a complete revision of the nomenclature and diagnosistic criteria for HRS-1, which was renamed HRS-AKI.⁷ Additionally, over recent years, greater granularity has been gained regarding the pathogenesis of HRS; it is now increasingly recognised that it is not a purely "functional" entity with haemodynamic derangements, but that systemic inflammation, oxidative stress and bile salt-related tubular damage may contribute significantly to its development. That is, HRS has an additional structural component that would not only make traditional diagnostic criteria less reliable, but would explain the lack of response to pharmacological treatment with vasoconstrictors plus albumin that correlates with a progressive increase in inflammation. Because classification, nomenclature, diagnostic criteria and pathogenic theories have evolved over the years since the traditional classification of HRS-1 and HRS-2 was first described, it was considered that all these novel aspects be reviewed and summarised in a position paper. The aim of this position paper authored by two hepatologists (members of ICA) and two nephrologists involved in the study of renal dysfunction in cirrhosis, is to complete the re-classification of HRS initiated by the ICA in 2012 and to provide an update on the definition, classification, diagnosis, pathophysiology and treatment of HRS.