Acute kidney injury in patients with cirrhosis: perils and promise

Early prediction of acute kidney injury in patients with gastrointestinal bleeding admitted to the intensive care unit based on extreme gradient boosting

Background

Acute kidney injury (AKI) is a common and important complication in patients with gastrointestinal bleeding who are admitted to the intensive care unit. The present study proposes an artificial intelligence solution for acute kidney injury prediction in patients with gastrointestinal bleeding admitted to the intensive care unit.

Methods

Data were collected from the eICU Collaborative Research Database (eICU-CRD) and Medical Information Mart for Intensive Care-IV (MIMIC-IV) database. The prediction model was developed using the extreme gradient boosting (XGBoost) model. The area under the receiver operating characteristic curve, accuracy, precision, area under the precision-recall curve (AUC-PR), and F1 score were used to evaluate the predictive performance of each model.

Results

Logistic regression, XGBoost, and XGBoost with severity scores were used to predict acute kidney injury risk using all features. The XGBoost-based acute kidney injury predictive models including XGBoost and XGBoost+severity scores model showed greater accuracy, recall, precision AUC, AUC-PR, and F1 score compared to logistic regression.

Conclusion

The XGBoost model obtained better risk prediction for acute kidney injury in patients with gastrointestinal bleeding admitted to the intensive care unit than the traditional logistic regression model, suggesting that machine learning (ML) techniques have the potential to improve the development and validation of predictive models in patients with gastrointestinal bleeding admitted to the intensive care unit.

Update on Assessment of Estimated Glomerular Filtration Rate in Patients With Cirrhosis

Kidney disease is associated with adverse outcomes in patients with cirrhosis including increased post-liver transplantation (LT) mortality. Therefore, diagnosis and staging of kidney disease are critical to timely implementation of treatment and have important implications for transplant eligibility. Serum creatinine (sCr) is a key component of the Model for End-Stage Liver Disease score in LT candidates, and sCr-based estimated glomerular filtration rate (eGFR) values play an important role in determining medical urgency for LT. However, the use of sCr to assess kidney function may be limited in the cirrhotic milieu due to decreased creatinine production, interference of bilirubin with some laboratory assays for sCr, and expansion of the volume of distribution of creatinine. Therefore, conventional eGFR equations perform poorly in patients with cirrhosis and may overestimate kidney function leading to delayed diagnosis of acute kidney injury or lower priority for LT in patients with a truly low glomerular filtration rate. In this review, we will provide an update on the use of sCr for diagnosis and staging of kidney disease in patients with cirrhosis, discuss the limitations of sCr-based eGFR equations, and discuss novel eGFR equations that have been developed in patients with cirrhosis.

Liver-HERO: hepatorenal syndrome-acute kidney injury (HRS-AKI) treatment with transjugular intrahepatic portosystemic shunt in patients with cirrhosis-a randomized controlled trial

BACKGROUND

Patients with cirrhosis and ascites (and portal hypertension) are at risk of developing acute kidney injury (AKI). Although many etiologies exist, hepatorenal AKI (HRS-AKI) remains a frequent and difficult-to-treat cause, with a very high mortality when left untreated. The standard of care is the use of terlipressin and albumin. This can lead to reversal of AKI, which is associated to survival. Nevertheless, only approximately half of the patients achieve this reversal and even after reversal patients remains at risk for new episodes of HRS-AKI. TIPS is accepted for use in patients with variceal bleeding and refractory ascites, which leads to a reduction in portal pressure. Although preliminary data suggest it may be useful in HRS-AKI, its use in this setting is controversial and caution is recommended given the fact that HRS-AKI is associated to cardiac alterations and acute-on-chronic liver failure (ACLF) which represent relative contraindications for transjugular intrahepatic portosystemic shunt (TIPS). In the last decades, with the new definition of renal failure in patients with cirrhosis, patients are identified at an earlier stage. These patients are less sick and therefore more likely to not have contraindications for TIPS. We hypothesize that TIPS could be superior to the standard of care in patients with HRS-AKI.

METHODS

This study is a prospective, multicenter, open, 1:1-randomized, controlled parallel-group trial. The main end-point is to compare the 12-month liver transplant-free survival in patients assigned to TIPS compared to the standard of care (terlipressin and albumin). Secondary end-point include reversal of HRS-AKI, health-related Quality of Life (HrQoL), and incidence of further decompensation among others. Once patients are diagnosed with HRS-AKI, they will be randomized to TIPS or Standard of Care (SOC). TIPS should be placed within 72 h. Until TIPS placement, TIPS patients will be treated with terlipressin and albumin. Once TIPS is placed, terlipressin and albumin should be weaned off according to the attending physician.

DISCUSSION

If the trial were to show a survival advantage for patients who undergo TIPS placement, this could be incorporated in routine clinical practice in the management of patients with HRS-AKI.

TRIAL REGISTRATION

Clinicaltrials.gov NCT05346393 . Released to the public on 01 April 2022.

Acute kidney injury defined by cystatin C may be superior for predicting the outcomes of liver cirrhosis with acute gastrointestinal bleeding

BACKGROUND & AIMS

Acute kidney injury (AKI) is conventionally evaluated by a dynamic change of serum creatinine (Scr). Cystatin C (CysC) seems to be a more accurate biomarker for assessing kidney function. This retrospective multicenter study aims to evaluate whether AKI re-defined by CysC can predict the in-hospital outcomes of patients with liver cirrhosis and acute gastrointestinal bleeding.

METHODS

Overall, 677 cirrhotic patients with acute gastrointestinal bleeding, in whom both Scr and CysC levels were detected at admissions, were screened. eGFR_Scr, eGFR_CysC, and eGFR_Scr-CysC were calculated. MELD-Na score and AKI were re-evaluated by CysC instead of Scr. Odds ratios (ORs) were calculated in the logistic regression analyses. The receiver operating characteristic (ROC) curve analyses were performed.

RESULTS

Univariate logistic regression analyses demonstrated that baseline Scr and CysC levels, eGFR_Scr, eGFR_CysC, eGFR_Scr-CysC, original MELD-Na score defined by Scr, MELD-Na score re-defined by CysC, and AKI re-defined by CysC, but not conventional AKI defined by Scr, were significantly associated with in-hospital death. ROC analyses showed that baseline CysC level, eGFR_Scr, eGFR_CysC, eGFR_Scr-CysC, original MELD-Na score defined by Scr, and MELD-Na score re-defined by CysC, but not baseline Scr level, could significantly predict the risk of in-hospital death.

CONCLUSIONS

AKI re-defined by CysC may be superior for predicting the in-hospital mortality of cirrhotic patients with acute gastrointestinal bleeding.

Acute Kidney Injury in Patients with Liver Disease

AKI is commonly encountered in patients with decompensated cirrhosis, and it is associated with unfavorable outcomes. Among factors specific to cirrhosis, hepatorenal syndrome type 1, also referred to as hepatorenal syndrome-AKI, is the most salient and unique etiology. Patients with cirrhosis are vulnerable to traditional causes of AKI, such as prerenal azotemia, acute tubular injury, and acute interstitial nephritis. In addition, other less common etiologies of AKI specifically related to chronic liver disease should be considered, including abdominal compartment syndrome, cardiorenal processes linked to cirrhotic cardiomyopathy and portopulmonary hypertension, and cholemic nephropathy. Furthermore, certain types of GN can cause AKI in cirrhosis, such as IgA nephropathy or viral hepatitis related. Therefore, a comprehensive diagnostic approach is needed to evaluate patients with cirrhosis presenting with AKI. Management should be tailored to the specific underlying etiology. Albumin-based volume resuscitation is recommended in prerenal AKI. Acute tubular injury and acute interstitial nephritis are managed with supportive care, withdrawal of the offending agent, and, potentially, corticosteroids in acute interstitial nephritis. Short of liver transplantation, vasoconstrictor therapy is the primary treatment for hepatorenal syndrome type 1. Timing of initiation of vasoconstrictors, the rise in mean arterial pressure, and the degree of cholestasis are among the factors that determine vasoconstrictor responsiveness. Large-volume paracentesis and diuretics are indicated to relieve intra-abdominal hypertension and renal vein congestion. Direct-acting antivirals with or without immunosuppression are used to treat hepatitis B/C-associated GN. In summary, AKI in cirrhosis requires careful consideration of multiple potentially pathogenic factors and the implementation of targeted therapeutic interventions.

Patterns of kidney dysfunction in acute-on-chronic liver failure: Relationship with kidney and patients' outcome

Impairment of kidney function is common in acute-on-chronic liver failure (ACLF). Patterns of kidney dysfunction and their impact on kidney and patient outcomes are ill-defined. Aims of the current study were to investigate patterns of kidney dysfunction and their impact on kidney and patient outcomes in patients with acute decompensation (AD) of cirrhosis, with or without ACLF. This prospective study includes 639 admissions for AD (232 with ACLF; 407 without) in 518 patients. Data were collected at admission and during hospitalization, and patients were followed up for 3 months. Urine samples were analyzed for kidney biomarkers. Most patients with ACLF (92%) had associated acute kidney injury (AKI), in most cases without previous chronic kidney disease (CKD), whereas some had AKI-on-CKD (70% and 22%, respectively). Prevalence of AKI in patients without ACLF was 35% (p < 0.001 vs. ACLF). Frequency of CKD alone was low and similar in both groups (4% and 3%, respectively); only a few patients with ACLF (4%) had no kidney dysfunction. AKI in ACLF was associated with poor kidney and patient outcomes compared with no ACLF (AKI resolution: 54% vs. 89%; 3-month survival: 51% vs. 86%, respectively; p < 0.001 for both). Independent predictive factors of 3-month survival were Model for End-Stage Liver Disease-Sodium score, ACLF status, and urine neutrophil gelatinase-associated lipocalin (NGAL). AKI is almost universal in patients with ACLF, sometimes associated with CKD, whereas CKD alone is uncommon. Prognosis of AKI depends on ACLF status. AKI without ACLF has good prognosis. Best predictors of 3-month survival are MELD-Na, ACLF status, and urine NGAL.

Serum IL-6 as a marker of disease progression in interstitial nephritis

OBJECTIVE

To investigate the mechanism of serum interleukin-6 (IL-6) change in disease progression of interstitial nephritis.

METHODS

This is a retrospective study. From November 2017 to November 2019, 87 patients with interstitial nephritis treated in our hospital were enrolled and divided into an acute group (n=42) and a chronic group (n=45) based on pathological results of renal biopsies. Forty healthy individuals after physical examination during the same period were enrolled into the reference group. Serum IL-6 levels were determined using the enzyme-linked immunosorbent assay (ELISA).

RESULTS

Among the three groups, patients in the acute group showed the highest IL-6 level (P<0.001). The acute group obtained higher serum advanced oxidation protein products (AOPP) levels and glomerular filtration rate (GFR) than the other two groups (P<0.05). The acute group showed lower levels of CD34⁺ [number of positive microvessels (MVs)/HP], a smaller type III collagen positive area, and a larger type IV collagen positive area than the chronic group (P<0.05). The acute group obtained higher levels of IL-27 and tumor necrosis factor-α (TNF-α) than the chronic group (P<0.001). The acute group had higher levels of serum creatinine (SCr), erythrocyte sedimentation rate (ESR), estimated glomerular filtration rate (eGFR), and 24-hour urine protein quantity (24 h UPQ) than the other groups (P<0.001). The combined detection of serum IL-6, TNF-α, and micro-albumin (mALB) outperformed the stand-alone approach (P<0.05). Serum IL-32 and kidney injury molecule-1 (KIM-1) levels in the acute and chronic group were positively correlated with SCr and 24 h UPQ (P<0.05).

CONCLUSIONS

Serum IL-6 shows a great potential as an important marker of disease progression in interstitial nephritis.

Characteristics of acute kidney injury and its impact on outcome in patients with acute-on-chronic liver failure

OBJECTIVE

Acute kidney injury (AKI) is a common and life-threatening complication of liver failure. The purpose of this study is to construct a nomogram and online calculator to predict the development of hospital-acquired acute kidney injury (HA-AKI) in patients with acute-on-chronic liver failure (ACLF), which may contribute to the prognosis of ACLF.

METHODS

574 ACLF patients were evaluated retrospectively. AKI was defined by criteria proposed by International Club of Ascites (ICA) and divided into community-acquired and hospital-acquired AKI (CA-AKI and HA-AKI). The difference between CA-AKI and HA-AKI, factors associated with development into and recovered from AKI periods. The risk factors were identified and nomograms were developed to predict the morbidity of HA-AKI in patients with ACLF.

RESULTS

Among 574 patients, 217(37.8%) patients had AKI, CA-AKI and HA-AKI were 56 (25.8%) and 161 (74.2%) respectively. The multivariate logistic regression model (KP-AKI) for predicting the occurrence of HA-AKI were age, gastrointestinal bleeding, bacterial infections, albumin, total bilirubin, blood urea nitrogen and prothrombin time. The AUROC of the KP-AKI in internal and external validations were 0.747 and 0.759, respectively. Among 217 AKI patients, 81(37.3%), 96(44.2%) and 40(18.4%) patients were with ICA-AKI stage progression, regression and fluctuated in-situ, respectively. The 90-day mortality of patients with AKI was 55.3% higher than non-AKI patients 21.6%. The 90-day mortality of patients with progression of AKI was 88.9%, followed by patients with fluctuated in-situ 40% and regression of AKI 33.3%.

CONCLUSIONS

The nomogram constructed by KP-AKI can be conveniently and accurately in predicting the development of HA-AKI, and AKI can increase the 90-day mortality significantly in ACLF patients. Trial registration Chinese clinical trials registry: ChiCTR1900021539.

Cirrosis hepática o falla hepática crónica agudizada: definición y clasificación

La cirrosis se considera el estadio crónico e irreversible de la lesión hepática. Su etiología es diversa y abarca causas como las infecciones víricas, tóxicos como el alcohol, medicamentos, patologías autoinmunes y otras. La descompensación de la cirrosis hepática es consecuencia de cambios fisiopatológicos que se dan con el tiempo como ascitis, peritonitis bacteriana espontánea, hemorragia del tubo digestivo, síndrome hepatorrenal, encefalopatía hepática o hipertensión portopulmonar, mientras que la falla hepática crónica agudizada debe considerarse como una entidad que debe diferenciarse de la anterior, ya que es una falla multiorgánica de curso rápido, por lo regular en pacientes hospitalizados en unidad de cuidado intensivo, a menudo secundaria a desencadenantes como estados de choque. El clínico debe identificarlas para su abordaje y evaluación. El método actual adecuado para estadificar esta entidad es el puntaje CLIFF SOFA, que evalúa la mortalidad a 28 y 90 días, permitiendo intervenciones adecuadas en cada caso.

Baseline serum cystatin C as a marker of acute kidney injury in patients with acute-on-chronic liver failure

BACKGROUND

A creatinine-based estimation of the renal function lags behind the onset of disease process. Cystatin C is a new marker for acute kidney injury (AKI). However, data are limited in patients with acute-on-chronic liver failure (ACLF). We evaluated serum cystatin C as an early predictor of AKI in patients with ACLF.

METHODS

In a prospective observational study, patients with ACLF and normal serum creatinine level were included in the study. Serum cystatin C was analyzed with the development of AKI and the disease outcome.

RESULT

Forty-seven patients (mean age: 43.26±16.34 years; male:female: 2.35:1) were included in the study. AKI developed in 34% of patients during the hospital stay. Receiver operating characteristic (ROC) curve analysis revealed that the best cutoff for baseline cystatin C was 1.47 mg/L with a sensitivity of 0.94 and specificity of 0.68. The cystatin C ((area under the curve [AUC]=0.853) performance was better than that of the creatinine (AUC=0.699), Child-Turcotte-Pugh (CTP) (AUC=0.661), and model for end-stage liver disease-sodium (MELD-Na) (AUC=0.641). In the univariate analysis, age, platelet count, creatinine, estimated glomerular filtration rate (eGFR)-modification of diet in renal disease (MDRD), cystatin C, and estimated glomerular filtration rate-serum cystatin C (eGFRcysC) were significantly associated with AKI in ACLF patients. Cystatin C was an independent positive predictor of AKI. Cystatin C was positively correlated with the MELD-Na scores (r=0.374 and p=0.009).

CONCLUSION

Our study supports previous studies reporting that serum cystatin C is a better predictor for AKI development compared to serum creatinine. Cystatin C may be used as an early marker for new-onset AKI in hospitalized patients with ACLF.

Serum Copeptin and Zinc-α2-glycoprotein Levels Are Novel Biomarkers of Tolvaptan Treatment in Decompensated Cirrhotic Patients with Ascites

Objective The efficacy of tolvaptan, an orally active vasopressin V2-receptor antagonist, has recently been reported in patients with massive ascites unresponsive to conventional diuretics. However, the effect of tolvaptan varies among patients. Recently, the prognostic role of the tolvaptan response in cases of decompensated liver cirrhosis (LC) has been attracting increasing attention. Using serum copeptin (vasopressin precursor), zinc-α2-glycoprotein (ZAG), cystatin C (renal biomarker), neutrophil gelatinase-associated lipocalin (NGAL) and liver-type fatty acid-binding protein (L-FABP), we explored which factors portend a good response to tolvaptan in LC patients with ascites. Methods We enrolled 113 LC patients and divided them into the tolvaptan treatment group and non-treatment group. Tolvaptan (3.75 or 7.5 mg/day) was administrated to 38 LC patients with ascites, and a follow-up assessment was performed after a 7-day tolvaptan treatment regimen. Results We determined the predictive ability for kidney and/or liver damage of serum copeptin, ZAG, cystatin C, NGAL and L-FABP levels in all patients. After 7-day tolvaptan treatment, 19 patients had lost more than 1.5 kg of body weight (Responders), while 19 showed no marked change in their body weight (Non-responders). Basal blood urea nitrogen (BUN) (p=0.0014), serum copeptin (p=0.0265) and serum ZAG levels (p=0.0142) were significantly higher in the Non-responders than in the Responders. BUN (odds ratio 7.43, p=0.0306), copeptin (odds ratio 9.12, p=0.0136) and ZAG (odds ratio 7.43, p=0.0306) were determined to be predictive factors of drug responsiveness using a multivariate logistic regression analysis. Conclusion Serum BUN, copeptin and ZAG levels predict the patient response to tolvaptan, even when measured prior to treatment.

Update on blood-based biomarkers for chronic liver diseases prognosis: Literature review and institutional experience

Liver cirrhosis is the final stage of chronic liver disease (CLD) and is associated with high morbidity and mortality. Various complications such as portal hypertension, ascites retention, hepatic encephalopathy, and hepatorenal syndrome deeply affect patient outcome. The most common tools to predict the outcome of a CLD patient include the following: assessing severity of portal hypertension; scoring systems such as the model of end-stage liver disease and Child-Pugh score and blood biomarkers related to complications and/or survival rate. In this article, we summarize recent studies of noninvasive markers for predicting impending complications related to CLD and discuss the clinical value of currently available blood biomarkers based on evidence from the literature. In addition, noninvasive blood biomarker assays for different prognostic functions were validated on 113 liver cirrhosis patients at our institution using Kaplan-Meier curve analysis to confirm that these markers can satisfactorily predict CLD-related patient death.

Cystatin C: best biomarker for acute kidney injury and estimation of glomerular filtration rate in childhood cirrhosis

The objective of the study was to evaluate the diagnostic and prognostic role of serum cystatin C, urinary neutrophil gelatinase-associated lipocalin (NGAL), and renal resistive index (RRI) in AKI among pediatric cirrhotics. The study included cirrhotic children under 18 years of age. AKI was diagnosed as per Kidney Diseases-Improving Global Outcomes (KDIGO) guidelines. All patients underwent measurement of serum cystatin C, urinary NGAL, and RRI at baseline, 3 months, and 6 months. eGFR was calculated using both creatinine- and cystatin-based equations. Of the 247 cirrhotics admitted during the study, 100 gave consent and were included. Forty-one fulfilled the KDIGO definition of AKI of whom 22 showed resolution. Two of these children had a repeat AKI at 2 and 4 months after initial AKI; both resolved with medical management. On logistic regression analysis, serum cystatin C (OR: 544.8, 95% CI: 24.4-12170, p < 0.0005) and urinary NGAL (OR: 1.006, 95% CI: 1001-1.012, p = 0.019) were found to be significantly associated with AKI. Cystatin C alone was the best biomarker for diagnosing AKI in children with decompensation (OR: 486.7, p < 0.0005) or spontaneous bacterial peritonitis (p = 0.02). eGFR calculated by serum cystatin C-based formulas was more reliable than that calculated by creatinine-based equations.Conclusion: Serum cystatin C is the best biomarker for diagnosis of AKI in pediatric cirrhotics, especially with decompensation and SBP. eGFR calculated on serum cystatin C-based equations is more reliable than creatinine-based ones. What is Known: • Acute kidney injury (AKI) is a common complication in cirrhotic adults. • Newer biomarkers have diagnostic and prognostic role in adult cirrhotics. What is New: • Serum cystatin C is a useful biomarker to identify acute kidney injury in cirrhotic children with decompensation. • Glomerular filtration rate calculation is more accurate by cystatin-based equations than creatinine-based equations.

Prevalence, risk factors, and short-term outcomes of postparacentesis acute kidney injury using revised criteria of the international club of ascites

Acute kidney injury (AKI) can become complicated after paracentesis due to extrarenal fluid loss and inadequate blood flow to the kidneys. The objective of this study was to explore the incidence and clinical implications of postparacentesis AKI.A retrospective cohort of 137 liver cirrhosis patients (mean age: 61.3 ± 11.8 years, male: 100 [73.0%], viral hepatitis: 93 [67.9%]) who underwent paracentesis was analyzed. The incidence of AKI as defined by the international club of ascites (ICA) criteria, the risk factors, and its impact on early mortality were all assessed.Thirty two patients (23.4%) developed AKI after paracentesis. In multivariate analysis, the Model for end-stage liver disease (MELD)-Na score was an independent factor associated with AKI development (odds ratio [OR], 1.14; 95% confidence interval [CI], 1.07-1.23) after paracentesis. The incidence of early mortality was significantly higher for those with AKI than without AKI (71.9% [23/32 patients] vs 11.4% [12/105 patients], P < .001). AKI (hazard ratio [HR], 7.56; 95% CI, 3.40-16.8) and MELD-Na score (HR, 1.08; 95% CI, 1.02-1.14) were independent factors associated with early mortality. In subgroup analysis, AKI after paracentesis was associated with significantly higher early mortality in both MELD-Na groups, that is, patients with a MELD-Na score >26 (87.5% vs 22.2%, P < .001) and those with a MELD-Na score ≤26 (56.3% vs 9.2%, P < .001).Postparacentesis AKI occurred frequently in cirrhotic patients. Furthermore, it was associated with early mortality. Baseline MELD-Na score was associated with AKI, indicating that careful attention is required for those with a higher MELD-Na score who are being considered for therapeutic paracentesis.

Comparison of tenofovir and entecavir in the development of acute kidney injury in cirrhotic chronic hepatitis B patients with refractory ascites

BACKGROUND AND AIM

Tenofovir disoproxil fumarate (TDF) and entecavir are effective antiviral medications that are recommended as first-line monotherapies for the treatment of chronic hepatitis B (CHB) infection, including decompensated liver cirrhosis with ascites. Acute kidney injury (AKI) commonly occurs in patients with cirrhosis and ascites. The aim of this study was to compare the development of AKI during TDF and entecavir treatment of CHB patients with cirrhotic refractory ascites.

METHODS

From January 2011 to April 2017, we identified patients who were diagnosed with cirrhosis with refractory ascites and received TDF or entecavir treatments at Kaohsiung Chang Gung Memorial Hospital. AKI was defined as an increase in serum creatinine of more than 0.3 mg/dL or 1.5-fold from baseline. All episodes of AKI were recorded and compared between those who received TDF and entecavir.

RESULTS

A total of 111 patients were enrolled in this retrospective study, of which 22 patients were treated with TDF and 89 were treated with entecavir. Patients with AKI episodes had a higher proportion of TDF treatment (P = 0.01), male (P = 0.023), hepatocellular carcinoma (P = 0.007), admission (P = 0.045), and mortality (P = 0.018). Logistic regression analysis illustrated that TDF treatment of patients with comorbidity was an independent risk factor for the development of AKI [odds ratio (OR), 3.756; 95% confidence interval (CI), 1.293-10.912; P = 0.015] and hepatorenal syndrome (OR, 7.651; 95% CI, 1.697-34.508; P = 0.008).

CONCLUSIONS

TDF treatment is a risk factor for AKI and HRS development in cirrhotic patients with refractory ascites in comparison with entecavir treatment, especially in patients with comorbidity.

Admission Serum Urea is a Better Predictor of Mortality than Creatinine in Patients With Acute-On-Chronic Liver Failure and Acute Kidney Injury

BACKGROUND

The occurrence of acute kidney injury (AKI) in acute-on-chronic liver failure (ACLF) negatively impacts the survival of patients. There are scant data on the impact of serum urea on outcomes in these patients. We performed this study to evaluate the relationship between admission serum urea and the survival in patients with ACLF and AKI.

METHODS

A prospective study was conducted on patients with ACLF (as per Asian Pacific Association for the Study of the Liver criteria) and AKI (as per Acute Kidney Injury Network criteria) hospitalized in the gastroenterology ward between October 2016 and May 2018. Demographic, clinical and laboratory parameters were recorded, and outcomes were compared in patients with respect to the admission serum urea level.

RESULTS

A total of 103 of 143 hospitalized patients with ACLF had AKI and were included as study subjects. The discrimination ability between survivors and the deceased was similar for serum urea levels (area under the receiver operating characteristic curve [AUROC] [95% confidence interval {CI}]: 28 days survival, 0.76 [0.67-0.85]; 90 days survival, 0.81 [0.72-0.91]) and serum creatinine levels (AUROC [95% CI]: 28 days survival, 0.75 [0.66-0.84]; 90 days survival: 0.77 [0.67-0.88]) in patients with ACLF and AKI. However, on multivariate analysis, admission serum urea (not serum creatinine) was an independent predictor of mortality in these patients both at 28 days (p = 0.001, adjusted hazard ratio [AHR]: 1.013 [1.005-1.021]) and 90 days (p = 0.001, AHR: 1.014 [1.006-1.022]).

CONCLUSION

Over two-thirds of patients with ACLF had AKI. The discrimination ability between survivors and the deceased was similar for both serum urea and serum creatinine levels. However admission serum urea was found to be a better predictor of mortality than serum creatinine in patients with ACLF and AKI.

Development of chronic kidney disease after acute kidney injury in patients with cirrhosis is common and impairs clinical outcomes

BACKGROUND & AIMS

Acute kidney injury (AKI) is common in cirrhosis and is associated with poor prognosis. In patients who survive after AKI, it is not known whether the acute injury leads to chronic impairment of kidney function (chronic kidney disease [CKD]). The aim of the study was to determine the frequency of CKD at 3 months after an AKI episode and its effects on patient outcomes.

METHODS

Patients admitted for complications of cirrhosis during a 6.5-year period were evaluated using the same protocol, with assessment of kidney function at regular intervals during and after hospitalization. CKD was defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73m² at 3 months after AKI.

RESULTS

A total of 409 patients (168 with AKI and 241 without AKI) were included. After 3 months, 97 patients with AKI and 188 patients without AKI had survived. Of the 97 patients with AKI, 24 had developed CKD at 3 months compared to only 2 of the 188 patients without AKI (25% vs. 1%, odds ratio 31; p <0.0001). Risk factors independently associated with CKD were nosocomial AKI and severity of AKI (stage ≥1B). At diagnosis of CKD, all patients had stage 3A CKD and one-quarter of them progressed to stages 3B and 4 after 1 year. The transition from AKI to CKD was associated with an increased rate of 3-month hospital readmission, increased frequency of AKI, bacterial infections, ascites, and refractory ascites and a trend towards a higher need for liver transplantation. Transplant-free survival was not impaired.

CONCLUSIONS

CKD frequently develops in patients with cirrhosis who survive AKI and has a negative impact on relevant clinical outcomes. The transition from AKI to CKD is common and should be considered a high-risk condition in patients with cirrhosis.

LAY SUMMARY

Episodes of acute impairment of kidney function are common in patients with cirrhosis. This study shows that the development of chronic impairment of kidney function is frequent in patients surviving these acute episodes and that it is associated with a higher risk of developing other complications of cirrhosis and to a higher rate of 3-month hospital readmissions.

Clinical Significance of Urinary Neutrophil Gelatinase-associated Lipocalin Levels in Defining the Various Etiologies of Acute Kidney Injury in Liver Cirrhosis Patients

Background/Aims

A diagnosis of hepatorenal syndrome (HRS) is based on a differential evaluation of acute kidney injury (AKI), which may aggravate the clinical course. This study assessed the clinical significance of the urinary neutrophil gelatinase- associated lipocalin (u-NGAL) levels in a differential diagnosis of AKI in patients with liver cirrhosis (LC).

Methods

Patients with LC who developed AKI were enrolled prospectively. Clinically, patients with AKI were classified into prerenal azotemia (PRA), HRS, and acute tubular necrosis (ATN) groups.

Results

Fifty-five patients (male, 74.5%) with LC who exhibited AKI upon admission were enrolled; 28, 9, and 18 patients were included in the PRA, HRS, and ATN groups, respectively. The baseline model for end-stage liver disease (MELD) scores was similar in the subgroups. The median event creatinine level, measured at the time of the AKI diagnosis, was similar in the HRS and ATN subgroups. On the other hand, the median event u-NGAL level differed significantly between the three subgroups (PRA, HRS, and ATN: 37 vs. 134 vs. 2,625 ng/mL, p=0.003). In particular, the median u-NGAL level of the HRS group was clearly different from those of the PRA (p<0.001) and ATN (p<0.001) groups. Multivariable analysis revealed the natural logarithm of the u-NGAL level (hazard ratio [HR] 1.77, p=0.031) and the MELD score (HR 1.17, p=0.027) to be independent prognostic factors for in-hospital mortality in patients with LC and AKI.

Conclusions

The median u-NGAL level differentiated HRS from ATN and served as a clinical indicator of in-hospital mortality for patients with LC and AKI.

Utility of Urinary Neutrophil gelatinase associated lipocalin (NGAL) in decompensated cirrhosis

Background and Aims:

Renal failure occurring in the setting of cirrhosis increases mortality by more than threefold. Serum creatinine, the conventional marker for renal dysfunction has inherent limitations in identifying and categorizing renal dysfunction in patients with chronic liver disease (CLD). Neutrophil gelatinase associated lipocalin (NGAL) is a novel biomarker which gets upregulated as early as 2-6 hours following the insult to renal tubules. In this study, we aim to check the utility of uNGAL to identify the different phenotypes of renal dysfunction in patients with CLD. We also intend to assess the utility of NGAL to predict 90-day transplant-free survival in patients with CLD.

Methods:

A total number of 120 adult patients, with cirrhosis of liver were recruited. Those with pre-existing renal parenchymal disease, receiving nephrotoxic medications, spontaneous bacterial peritonitis, septic shock, proteinuria, hematuria, urinary tract infection and anuria were excluded. Urine samples for NGAL was measured at admission and at 48 hours thereafter. Patients were followed up for 90 days post admission.

Results:

Among the study population, 16 patients (13.3%) had normal kidney function, 43 (35.8%) had prerenal azotemia and 54 (45%) had Hepatorenal Syndrome (HRS - AKI) and 7 (5.8%) had acute tubular necrosis (ATN). Urinary NGAL (uNGAL) levels were considerably lower in patients with normal kidney function and prerenal azotemia. An uNGAL level of 124 ng/ml on admission could distinguish severe forms of renal injury, with a sensitivity of 86% and specificity of 84%. The non survivors had higher uNGAL levels at admission [209.6 ng/ml (118.7-376.8) vs. 123 (33.6-344.3); P = 0.013].The receiver operated curves for uNGAL and serum creatinine at admission did not show any significant difference for predicting 90 day mortality (AUC for uNGAL: 0.632 vs 0.580 for serum creatinine; difference in AUC 0.053, P value 0.17).

Conclusion:

uNGAL levels are elevated in patients with HRS-AKI and ATN. A higher uNGAL level at admission was suggestive of severe renal dysfunction. An elevated uNGAL on admission is associated with inferior survival. However, uNGAL is not superior to serum creatinine in predicting 90-day mortality.

Paracentesis-induced acute kidney injury in decompensated cirrhosis - prevalence and predictors

AIM OF THE STUDY

A subgroup of cirrhotic patients undergoing therapeutic paracentesis develop acute kidney injury (AKI) despite adequate colloidal replacement.The aim of the study was to determine the prevalence and predictors of paracentesis-induced AKI in cirrhotic patients with normal baseline renal parameters and adequate colloidal replacement.

MATERIAL AND METHODS

This prospective, observational analytical study was undertaken between April 2015 and April 2017. All patients undergoing therapeutic paracentesis were enrolled as per inclusion and exclusion criteria. Based on Acute Kidney Injury Network (AKIN) criteria for AKI, comparative analysis was performed between those developing and not developing AKI for demography, renal parameters, frequency and quantity of paracentesis per session. Univariate and multivariate regression analyses were performed to determine the predictors of AKI.

RESULTS

Altogether, 177 patients underwent 859 therapeutic paracenteses. Ninety-four paracentesis sessions resulted in an AKI (10.9%). The median number of paracenteses was 10 (range 1-25) and the median volume of fluid drained per paracentesis was 6 l (1-20 l). In univariate analysis, younger age (p < 0.02), higher MELD (Model For End-Stage Liver Disease) score (p < 0.0001), CTP (Child-Turcotte-Pugh) class C (p < 0.017) and prior history of renal dysfunction (p < 0.0001) were significantly associated with AKI. For each liter of fluid drained, the risk of AKI increased by 1.24 times. Frequency of paracentesis did not influence the AKI. In multivariate logistic regression, the significant predictors of AKI were past renal dysfunction, a higher MELD and volume of fluid tapped at paracentesis.

CONCLUSIONS

Post-paracentesis AKI occurs in 10.9% of cases, despite adequate colloid replacement. For each 1 l of fluid drained during paracentesis, the risk of AKI increased by 1.24 times.

Renal impairment is associated with increased risk of mortality in patients with cirrhosis: A retrospective cohort study

Although renal impairment is a frequent complication in cirrhosis that is associated with a poor prognosis, little has been reported on the clinical significance of renal impairment in cirrhosis in Japan. This retrospective study assessed the impact of renal impairment on mortality in Japanese cirrhosis patients taking conventional diuretics.A total of 157 patients with cirrhosis receiving diuretic treatment were evaluated for the presence and status of renal impairment, defined as an increase in serum creatinine of ≥ 0.3 mg/dL or by ≥ 50%, and then classified according to the International Club of Ascites (ICA)-Acute Kidney Injury (AKI) staging system.Eighty of 157 (51%) patients fulfilled the criteria for renal impairment. Thirty-four (43%) patients had ICA-AKI stage 1, 32 (40%) stage 2, and 14 (18%) stage 3. Multivariate analysis revealed female gender (hazard ratio [HR] = 0.407, 95% confidence interval = 0.193-0.857; P = .018), ALT ≥35 IU/L (HR = 3.841, 95% confidence interval = 1.785-8.065; P = .001), and the presence of renal impairment (HR = 4.275, 95% confidence interval = 1.962-9.312; P < .001) as independent factors significantly increasing the risk of mortality. Cumulative survival rates increased significantly with ICA-AKI stage (log-rank test, P = .009).Renal impairment was a predictive marker of mortality in Japanese patients with cirrhosis. Stratification according to ICA-AKI criteria of kidney function impairment may be a good prognostic indicator of cirrhosis outcome.

The Use of Selected Urine Chemistries in the Diagnosis of Kidney Disorders

Urinary chemistries vary widely in both health and disease and are affected by diet, volume status, medications, and disease states. When properly examined, these tests provide important insight into the mechanism and therapy of various clinical disorders that are first detected by abnormalities in plasma chemistries. These tests cannot be interpreted in isolation, but instead require knowledge of key clinical information, such as medications, physical examination, and plasma chemistries, to include kidney function. When used appropriately and with knowledge of limitations, urine chemistries can provide important insight into the pathophysiology and treatment of a wide variety of disorders.

A Validated Score Predicts Acute Kidney Injury and Survival in Patients With Alcoholic Hepatitis

Identifying patients at high risk for acute kidney injury (AKI) during hospitalization among patients admitted with severe alcoholic hepatitis (AH) is an unmet clinical need. We performed a multicentric prospective cohort study using data from 4 different cohorts on well-characterized patients hospitalized with severe AH. Data collected on 773 AH patients from 4 cohorts across the globe were randomly split into test (n = 390) and validation (n = 383) cohorts. We found that 32% of the patients developed inpatient AKI in the test cohort. Approximately 60% of patients met criteria for systemic inflammatory response syndrome (SIRS) at admission. Hepatic encephalopathy, SIRS, and Model for End-Stage Liver Disease score at admission predicted inpatient AKI with odds ratios of 3.86, 2.24, and 1.14, respectively. The AKI risk score developed using these predictors stratified risk of inpatient AKI to low (score <3), moderate (3-4), and high (>4). These findings were replicated in the validation cohort. In the whole study cohort, patients with AKI had a lower 90-day survival (53% versus 77%; P < 0.001). Those with AKI risk score of >4 had significantly lower 90-day survival as compared with those with risk scores between 3 and 4 and <3 (47% versus 68% versus 88%; P < 0.001). In conclusion, AKI occurs frequently in AH patients and negatively impacts short-term mortality. The AKI risk score is useful in identifying patients at high risk for inpatient AKI and may be useful for developing new therapeutic strategies to prevent AKI in patients with AH.

Acute Kidney Injury in Patients Undergoing Chronic Hepatitis C Virus Treatment With Ledipasvir/Sofosbuvir

Ledipasvir-sofosbuvir, a once-a-day, oral combination pill, was approved in 2014 for the treatment of chronic hepatitis C infection. Initial trials did not comment on nephrotoxicity; however, recent data suggest a risk of acute kidney injury (AKI) with the use of the medication. We assessed the rates of AKI in patients undergoing ledipasvir-sofosbuvir in a large, urban tertiary care center. This single-center retrospective observation study included all patients undergoing therapy from October 1, 2014, to October 1, 2015. Rates of AKI, defined by more than a 0.3 mg/dL increase in serum creatinine level, were calculated. Patients were followed 12 weeks after therapy to assess for sustained viral response as well as to assess for improvement of AKI after completion of therapy, defined by less than 0.2 mg/dL above baseline serum creatinine. In total, 197 patients were included in the final analysis who had completed ledipasvir-sofosbuvir therapy and completed laboratory values. Among the patients treated, 38 (19%) had AKI during therapy. An additional 4 (2%) had AKI at the end of therapy. Of the 38 patients who experienced AKI, 20 (53%) had improvement in serum creatinine to less than 0.2 mg/dL above their baseline. When comparing for chronic kidney disease (CKD) stage, those with CKD I or II experienced AKI 17% of the time compared with 47% of the time in CKD III or worse (P = 0.005). Conclusion: AKI was seen in nearly one-fifth of our patients, and patients with CKD stage III or worse are at increased risk. Although ledipasvir-sofosbuvir is generally safe in the general population, close monitoring of renal function is recommended.

Cystatin C predicts acute kidney injury and mortality in cirrhotics: A prospective cohort study

BACKGROUND & AIMS

Acute kidney injury is a frequent and ominous complication in cirrhosis. An episode of AKI damages the functional nephron mass, compromising the renal functional reserve. We aimed to study the incidence of AKI, probability of subsequent episodes, whether AKI itself predisposes to future AKI and the reliability of serum cystatin C(sCyC) as a biomarker in a prospective cohort of cirrhotics.

PATIENTS AND METHODS

Five hundred and thirty-one cirrhotics without ongoing AKI were followed for development/resolution of AKI. Predictive models for AKI and mortality were developed and validated (Gr. A, Derivative cohort [n = 273], Gr. B, Validation Cohort [n = 258]).

RESULTS

365 episodes of AKI occurred in 233 patients; yielding a mean of 1.56 episodes of AKI per patient. In Gr. A and B, 97 (35.5%) and 78 (30%) patients had prior AKI episodes and were predisposed to further attacks (Gr. A, HR 3.9, 95% CI 2.7-5.6, Gr. B, HR 3.6, 95% CI 2.5-5.4). AKI was thus an independent predictor of the development of new AKI(P < .05) and this risk increased significantly with increase in the number of AKI episodes (P < .001). S.CysC but not s.Cr was an independent predictor of new AKI on multivariate analysis. "AKI-Score" incorporating CysC; and the addition of Cyst into components of MELD, that is the "MELD-Cystatin" score predicted the development of AKI and mortality, respectively, and performed significantly better than the MELD and CTP scores.

CONCLUSIONS

An episode of AKI itself predisposes to subsequent attacks of AKI in cirrhotics. Scores incorporating CysC can accurately predict the development of AKI and mortality in these patients.

Plasma cystatin C is a predictor of renal dysfunction, acute-on-chronic liver failure, and mortality in patients with acutely decompensated liver cirrhosis

The development of acute-on-chronic liver failure (ACLF) in patients with liver cirrhosis is associated with high mortality rates. Renal failure is the most significant organ dysfunction that occurs in ACLF. So far there are no biomarkers predicting ACLF. We investigated whether cystatin C (CysC) and neutrophil gelatinase-associated lipocalin (NGAL) can predict development of renal dysfunction (RD), hepatorenal syndrome (HRS), ACLF, and mortality. We determined the plasma levels of CysC and NGAL in 429 patients hospitalized for acute decompensation of cirrhosis in the EASL-CLIF Acute-on-Chronic Liver Failure in Cirrhosis (CANONIC) study. The patients were followed for 90 days. Patients without RD or ACLF at inclusion but with development of either had significantly higher baseline concentrations of CysC and NGAL compared to patients without. CysC, but not NGAL, was found to be predictive of RD (odds ratio, 9.4; 95% confidence interval [CI], 1.8-49.7), HRS (odds ratio, 4.2; 95% CI, 1.2-14.8), and ACLF (odds ratio, 5.9; 95% CI, 1.3-25.9). CysC at day 3 was not found to be a better predictor than baseline CysC. CysC and NGAL were both predictive of 90-day mortality, with hazard ratios for CysC of 3.1 (95% CI, 2.1-4.7) and for NGAL of 1.9 (95% CI, 1.5-2.4).

CONCLUSION

Baseline CysC is a biomarker of RD, HRS, and ACLF and an independent predictor of mortality in patients with acutely decompensated liver cirrhosis, though determining CysC at day 3 did not provide any benefit; while NGAL is also associated with short-term mortality, it fails to predict development of RD, HRS, and ACLF. Baseline CysC may help to identify patients at risk earlier and improve clinical management. (Hepatology 2017;66:1232-1241).

Beneficial and harmful effects of nonselective beta blockade on acute kidney injury in liver transplant candidates

Nonselective beta-blockers (NSBBs) have played an important role in the prevention of portal hypertensive bleeding in patients with cirrhosis. However, recent studies have suggested that NSBBs may be harmful in some patients with end-stage liver disease. The purpose of this article is to evaluate the association between use of NSBB and the incidence of acute kidney injury (AKI). We conducted a nested case-control study in a cohort of liver transplant wait-list registrants. Each patient with AKI was matched to a control by the Model for End-Stage Liver Disease-Na score, age, serum creatinine, and follow-up duration. Out of a total of 2361 wait-list registrants, 205 patients developed AKI after a median follow-up duration of 18.2 months. When compared with matched controls, ascites (79.0% versus 51.7%) and non-Caucasian race (16.6% versus 7.8%) were more common among the cases. The frequency of NSBB use was higher among the cases than controls, albeit insignificantly (45.9% versus 37.1%; P = 0.08). In multivariate analyses, the impact of nonselective beta blockade on the development of AKI was dependent on the presence of ascites: nonselective beta blockade in patients with ascites significantly increased the risk of AKI (hazard ratio [HR], 3.31; 95% confidence interval [CI], 1.57-6.95), whereas in patients without ascites, NSBB use reduced it (HR, 0.19; 95% CI, 0.06-0.60). Potential benefits and harms of a NSBB in terms of AKI depend on the presence of ascites in liver transplant candidates. NSBB therapy in patients with cirrhosis may need to be individualized. Liver Transplantation 23 733-740 2017 AASLD.

Evaluation of Absolute Serum Creatinine Changes in Staging of Cirrhosis-Induced Acute Renal Injury and its Association with Long-term Outcomes

BACKGROUND/AIMS

To assess the prognostic accuracy of absolute serum creatinine (sCr) changes ('Delta-sCr') on the long-term outcomes in cirrhotic patients, and evaluate the performance of the 'Delta-sCr' approach to stage acute kidney injury (AKI), compared with the Kidney Disease Improving Global Outcomes (KDIGO) criteria.

METHODS

We conducted a retrospective analysis of 333 hospitalized patients. We classified AKI stages using two methods: 1) KDIGO AKI criteria; 2) 'Delta-sCr' system, defined by the difference between the baseline and the peak sCr value during the hospitalization. The end point was the hazard of 1-year death.

RESULTS

The prevalence of AKI in cirrhotic patients was 18.01% by the KDIGO criteria, and 25.22% by the 'Delta-sCr' system. On multivariable Cox hazard analysis, both of the two methods were independent predictive factors of death ('Delta-sCr' system: OR=2.911, p<0.001), (KDIGO criteria: OR=2.065, p<0.001). However, the 'Delta-sCr' system provided a modest improvement in classification over the KDIGO criteria with a net reclassification improvement (NRI) of 28.7% (p<0.001) and integrated discrimination improvement (IDI) of 7.5% (p=0.03). And the predictive value of the 'Delta-sCr' system could be significantly improved (p=0.006), when combined with age and MELD score.

CONCLUSION

The Delta-sCr is associated with the 1-year mortality. And the 'Delta-sCr' system may optimize the discrimination of risk prediction.

Reduced impact of renal failure on the outcome of patients with alcoholic liver disease undergoing liver transplantation

BACKGROUND & AIMS

Pretransplant renal failure is commonly reported to be a poor prognostic indicator affecting survival after liver transplantation (LT). However, whether the impact of renal failure on patient outcome varies according to the aetiology of the underlying liver disease is largely unknown.

METHODS

We investigated the association between renal failure at the time of LT and patient outcome in patients with alcoholic liver disease (ALD) (n = 6920), non-alcoholic steatohepatitis (NASH) (n = 2956) and hepatitis C (HCV) (n = 14 922) using the United Network for Organ Sharing (UNOS) database between February 2002 and December 2013. A total of 24 798 transplant recipients were included.

RESULTS

The presence of renal failure was more frequently seen in patients with ALD (23.95%) and NASH (23.27%) compared to patients with HCV (19.38%) (P < 0.001). In multivariate analysis, renal failure was an independent predictor of poor survival. Renal failure showed detrimental effect on patient survival in the overall series (HR = 1.466, P < 0.0001). Importantly, the impact of renal failure was less marked in patients with ALD (HR = 1.31, P < 0.0001) than in patients with NASH (HR = 1.73, P < 0.0001) or HCV (HR = 1.52, P < 0.0001). Despite a higher model for end-stage liver disease (MELD) score at the time of LT, ALD patients with renal failure had better long-term prognosis than non-ALD patients.

CONCLUSIONS

Renal failure at the time of LT conferred a lower patient and graft survival post-LT. However, renal failure has less impact on the outcome of patients with ALD than that of patients with non-alcoholic liver disease after LT.

Neutrophil gelatinase-associated lipocalin and cystatin C in cirrhosis and portal hypertension: Relations to organ extraction and dysfunction

BACKGROUND AND AIMS

Early detection of renal dysfunction in cirrhosis is important, and several renal biomarkers have been put forward. Neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C are markers of renal dysfunction, but relations to splanchnic and systemic hemodynamics and kinetics are sparsely studied in cirrhosis. In patients with cirrhosis and portal hypertension, we studied plasma levels and renal, hepatic, and peripheral extraction of NGAL and cystatin C and relations to patients characteristics, liver dysfunction, and hemodynamics.

METHODS

Forty-five cirrhotic patients (Child class A/B/C:15/15/15) and 15 controls were evaluated with a full clinical, biochemical, and hemodynamic assessment. Urine and regional plasma concentrations of NGAL and cystatin C were measured.

RESULTS

There was no significant difference in circulating or hepatic NGAL or cystatin C between all patients and controls but a trend towards increased levels with increasing Child class. In addition, there was a significant renal but no hepatic or systemic extraction of both NGAL and cystatin C (P < 0.001). Plasma NGAL correlated with glomerular filtration rate (r = -0.56, P < 0.0001), and hepatic venous pressure gradient (r = 0.34,P = 0.02) and urinary NGAL correlated with heart rate (r = 0.58, P= 0.007), blood pressure (r = -0.46, P < 0.05), cardiac output (r = 0.45, P < 0.05), and systemic vascular resistance (SVR) (r = -0.48, p < 0.05). Plasma cystatin C correlated with hepatic venous pressure gradient (r = 0.45, P < 0.005), blood pressure (-0.40, P < 0.01), and glomerular filtration rate (r = 0.98, P < 0.000).

CONCLUSIONS

Extractions of NGAL and cystatin C levels seem largely unaffected by the severity of liver disease in cirrhosis with a renal extraction. These biomarkers therefore have the potential of being both valuable in diagnosing renal failure and reflecting the degree of portal hypertension and systemic haemodynamic changes.

Clinical characteristics and long-term outcome of acute kidney injury in patients with HBV-related acute-on-chronic liver failure

Acute kidney injury (AKI) is a common complication in patients with decompensated cirrhosis and is also an important cause for poor outcome. This study aimed at investigating the clinical characteristics and long-term prognosis of AKI in patients with hepatitis B virus (HBV)-related acute-on-chronic liver failure (ACLF). A total of 1167 patients with HBV-related ACLF from January 2010 to January 2015 were enrolled and divided into two groups, AKI group (n=308) and non-AKI group (n=859). All patients were followed up to investigate clinical characteristics, long-term overall survival (OS) and risk factors. AKI occurrence was found to be 26.4% in patients with HBV-related ACLF. The patients in the AKI group and the non-AKI group had a 30-day OS of 44.8% and 70.3%, 90-day OS of 17.9% and 55.4%, and 1-year OS of 15.6% and 51.2%, respectively. Significant differences were observed in the 30-day, 90-day and 1-year OS among subgroups with different AKI stages. It was found that high WBC, neutrophil, ALT and MELD score were risk factors for 30-day mortality, whereas hepatic encephalopathy, high MELD score, mean arterial pressure and PLT were risk factors for 90-day mortality. Two criteria, the KDIGO and AKIN, showed parallel results in staging AKI in patients with HBV-related ACLF (κ=0.807, P<.001). AKI is closely associated with increased short-term mortality in Chinese HBV-related ACLF patients, particularly in those with infection and high MELD score. Both KDIGO and AKIN criteria can be used for staging AKI in patients with HBV-related ACLF.

Relevance of New Definitions to Incidence and Prognosis of Acute Kidney Injury in Hospitalized Patients with Cirrhosis: A Retrospective Population-Based Cohort Study

BACKGROUND

The implementation of new serum creatinine (SCr)-based criteria for acute kidney injury (AKI) has brought to light several areas of uncertainty in patients with cirrhosis.

STUDY DESIGN

Population-based cohort study.

SETTING & PARTICIPANTS

Adults with cirrhosis hospitalized between 2002-2012.

PREDICTOR

We aimed to address the prognostic implications of the new AKI criteria in cirrhosis.

OUTCOMES

Baseline kidney function was defined from all outpatient SCr within 3 months before hospitalization. Cox proportional hazards models were fit to examine associations between AKI, renal recovery and all-cause mortality.

RESULTS

4,733 patients were studied. The 30-day mortality was higher for participants with AKI (43.9% vs 8.5%; p-value<0.001), and increased with AKI severity. The highest incidence of AKI occurred when the lowest SCr within the three months prior to admission was used to define baseline. The hazard ratio for mortality using the lowest SCr within 3 months and the closest pre-admission SCr (definition suggested by the recent consensus guideline) were similar, validating the use of the latter measure. As compared to patients without AKI, stage 1 AKI with maximum SCr ≤132 mmol/L remained associated with a 3.5-fold increased hazard of death at 30 days (95% CI 2.6 to 4.7).

LIMITATIONS

As an observational study, the results were vulnerable to residual confounding and ascertainment bias in the use of laboratory data to identify AKI. We did not have access to liver function or disease etiology variables and were unable to adjust for these in our analyses.

CONCLUSIONS

These results confirm the graded relationship between AKI severity, renal recovery, and mortality and further clarify previously discordant reports about the prognostic relevance of new AKI criteria in patients with cirrhosis.

Urine biochemistry assessment in critically ill patients: controversies and future perspectives

In the past, urine biochemistry was a major tool in acute kidney injury (AKI) management. Classic papers published some decades ago established the values of the urine indices which were thought to distinguish "pre-renal" (functional) AKI attributed to low renal perfusion and "renal" (structural) AKI attributed to acute tubular necrosis (ATN). However, there were a lot of drawbacks and limitations in these studies and some recent articles have questioned the utility of measuring urine electrolytes especially because they do not seem to adequately inform about renal perfusion nor AKI duration (transient vs. persistent). At the same time, the "pre-renal" paradigm has been consistently criticized because hypoperfusion followed by ischemia and ATN does not seem to explain most of the AKI developing in critically ill patients and distinct AKI durations do not seem to be clearly related to different pathophysiological mechanisms or histopathological findings. In this new context, other possible roles for urine biochemistry have emerged. Some studies have suggested standardized changes in the urine electrolyte composition preceding increases in serum creatinine independently of AKI subsequent duration, which might actually be due to intra-renal microcirculatory changes and activation of sodium-retaining mechanisms even in the absence of impaired global renal blood flow. In the present review, the points of controversy regarding urine biochemistry assessment were evaluated as well as future perspectives for its role in AKI monitoring. An alternative approach for the interpretation of measured urine electrolytes is proposed which needs further larger studies to be validated and incorporated in daily ICU practice.

Changes in Kidney Function After Transjugular Intrahepatic Portosystemic Shunts Versus Large-Volume Paracentesis in Cirrhosis: A Matched Cohort Analysis

BACKGROUND

Patients with cirrhosis and refractory ascites have physiologic and hormonal dysregulation that contributes to decreased kidney function. Placement of a transjugular intrahepatic portosystemic shunt (TIPS) can reverse these changes and potentially improve kidney function. We sought to evaluate change in estimated glomerular filtration rate (eGFR) following TIPS placement.

STUDY DESIGN

Retrospective, matched cohort analysis.

SETTINGS & PARTICIPANTS

Patients who underwent first-time TIPS placement for refractory ascites in 1995 to 2014. Frequency matching was used to generate a comparator group of patients with cirrhosis and ascites treated with serial large-volume paracentesis (LVP) in a 1:1 fashion.

PREDICTOR

TIPS placement compared to serial LVP.

OUTCOME

Change in eGFR over 90 days' follow-up.

MEASUREMENTS

Multivariable regression stratified by baseline eGFR<60 versus ≥60mL/min/1.73m(2); analysis of effect modification between TIPS placement and baseline eGFR.

RESULTS

276 participants (TIPS, n=138; serial LVP, n=138) were analyzed. After 90 days, eGFRs increased significantly after TIPS placement in participants with baseline eGFRs<60mL/min/1.73m(2) compared to treatment with serial LVP (21 [95% CI, 13-29] mL/min/1.73m(2); P<0.001) and was no different in those with eGFRs≥60mL/min/1.73m(2) (1 [95% CI, -9 to 12] mL/min/1.73m(2); P=0.8). There was significant effect modification between TIPS status and baseline eGFR (P=0.001) in a model that included all participants.

LIMITATIONS

Outcomes restricted by clinically recorded data; clinically important differences may still exist between the TIPS and LVP cohorts despite good statistical matching.

CONCLUSIONS

TIPS placement was associated with significant improvement in kidney function. This was most prominent in participants with baseline eGFRs<60mL/min/1.73m(2). Prospective studies of TIPS use in populations with eGFRs<60mL/min/1.73m(2) are needed to evaluate these findings.

Cirrhotic Multiorgan Syndrome

Patients with cirrhosis and portal hypertension are at an increased risk of the development of circulatory dysfunction that may potentially result in multiple organ failure. Apart from the liver, this may involve the heart, lungs, kidneys, the immune system, the adrenal glands, and other organ systems. As the disease progresses, the circulation becomes hyperdynamic, and signs of cardiac, pulmonary, and renal dysfunction are observed, in addition to reduced survival. Infections and an altered cardiac function known as cirrhotic cardiomyopathy may be precipitators for the development of other complications such as hepatorenal syndrome. In patients with chronic organ dysfunction, various precipitating events may induce an acute-on-chronic renal failure and acute-on-chronic liver failure that negatively affect the prognosis. Future research on the pathophysiologic mechanisms of the complications and the precipitating factors is essential to understand the basics of the treatment of these challenging conditions. The aim of the present review is to focus on the development and precipitating factors of various organ failures in patients with decompensated cirrhosis.

Creatinine Change on Vasoconstrictors as Mortality Surrogate in Hepatorenal Syndrome: Systematic Review & Meta-Analysis

BACKGROUND AND AIMS

Hepatorenal syndrome is a severe complication of cirrhosis and associates with significant mortality. Vasoconstrictor medications improve renal function in patients with hepatorenal syndrome. However, it is unclear to what extent changes in serum creatinine during treatment may act as a surrogate for changes in mortality. We have performed a meta-analysis of randomized trials of vasoconstrictors assessing the association between changes in serum creatinine, taken as a continuous variable, and mortality, both while on treatment and during the follow-up period for survivors.

METHODS

The electronic databases of PubMed, Web of Science and Embase were searched for randomized trials evaluating the efficacy of vasoconstrictor therapy for treatment of HRS type 1 or 2. The relative risk (RR) for mortality was calculated against delta creatinine. The proportion of treatment effect explained (PTE) was calculated for delta creatinine.

RESULTS

Seven trials enrolling 345 patients were included. The correlation between delta creatinine and ln (RR) was moderately good (R2 = 0.61). The intercept and parameter estimate indicated a fall in creatinine while on treatment of 1 mg/dL resulted in a 27% reduction in RR for mortality compared to the control arm. In patients surviving the treatment period, a fall in creatinine while on treatment of 1 mg/dL resulted in a 16% reduction in RR for post-treatment mortality during follow-up. The PTE of delta creatinine for overall mortality was 0.91 and 0.26 for post-treatment mortality.

CONCLUSIONS

Changes in serum creatinine in response to vasoconstrictor therapy appear to be a valid surrogate for mortality, even in the period following the completion of treatment.

Neutrophil Gelatinase-Associated Lipocalin: A New Marker of Renal Function in C-Related End Stage Liver Disease

Background/Aims. Renal impairment is a common complication of cirrhosis. Serum creatinine is less sensitive in these patients. Measurement of the glomerular filtration rate (GFR) is the gold standard but time consuming. The aim is to validate plasma NGAL (pNGAL) and urinary NGAL (uNGAL) as markers of renal function in patients with HCV related cirrhosis. Patient and Methods. One hundred HCV related end stage liver cirrhosis patients were randomized into two groups: Group I (n = 35), patients with GFR < 60 mL/m measured by isotope scanning of the kidney (Renogram), and Group II (n = 65), patients with GFR ≥ 60 mL/m. The pNGAL and uNGAL were measured within 2 days of the Renogram. Results. Both groups were matched with age, sex, and Child Pugh score. There was statistically significant difference between both groups regarding serum creatinine (1.98 ± 1.04 versus 1.38 ± 0.88 mg/dL; p = 0.003) and pNGAL level (5.79 ± 2.06 versus 7.25 ± 3.30 ng/dL; p = 0.019). Both groups were comparable (p > 0.05) for the uNGAL (6.00 ± 0.78 versus 6.03 ± 0.96 ng/mL). Unlike uNGAL, the pNGAL positively correlated with total GFR by Renogram (r = 0.3; p = 0.001). With a cutoff ≥4 ng/mL, pNGAL had 94.3% sensitivity and 1.5% specificity and PPV = 34, NPV = 33.3, LR+ = −175.1, and LR− = −60.6. Conclusion. The pNGAL is a promising marker of the renal function in patients with cirrhosis.

Acute kidney injury in patients with chronic liver disease

Acute kidney injury (AKI) is a frequent clinical event in patients with liver disease, compounding their prognosis. Furthermore, it is likely that the occurrence of AKI has a detrimental impact on the subsequent renal function and the long-term survival of these patients. Recently, some authors advocated the use of new diagnostic criteria for detecting acute kidney injury in patients with cirrhosis. These criteria are based on the rapidity and extent of the creatinine increase comparing to the basal creatinine and also on the kinetics of diuresis decrease. Although their validity in this population requires further studies to be clearly established, these new criteria could have two advantages: (1) to allow earlier diagnosis of AKI and, thus, hepatorenal syndrome for which earlier intervention could improve patients’ survival; and (2) to promote more intensive monitoring of renal function in these patients with high risk of AKI. Finally, recent practice guidelines about the prevention and treatment of general AKI have been published which should be useful in optimising the management of AKI in cirrhotic patients.

Renal dysfunction in cirrhosis

PURPOSE OF REVIEW

Renal dysfunction causes significant morbidity in cirrhotic patients. Diagnosis is challenging because it is based on serum creatinine, which is used to calculate estimated glomerular filtration rate, which itself is not an ideal measure of renal function in patients with cirrhosis. Finding the exact cause of renal injury in patients with cirrhosis remains problematic due to the limitations of the current diagnostic tests. The purpose of this review is to highlight studies used to diagnose renal dysfunction in patients with renal dysfunction and review current treatments.

RECENT FINDINGS

New diagnostic criteria and classification of renal dysfunction, especially for acute kidney injury (AKI), have been proposed in hopes of optimizing treatment and improving outcomes. New biomarkers that help to differentiate structural from functional AKI in cirrhotic patients have been developed, but require further investigation. Vasoconstrictors are the most commonly recommended treatment of hepatorenal syndrome (HRS). Given the high mortality in patients with type 1 HRS, all patients with HRS should be evaluated for liver transplantation. When renal dysfunction is considered irreversible, combined liver-kidney transplantation is advised.

SUMMARY

Development of new biomarkers to differentiate the different types of AKI in cirrhosis holds promise. Early intervention in cirrhotic patients with renal dysfunction offers the best hope of improving outcomes.

Neutrophil Gelatinase-Associated Lipocalin: A New Marker of Renal Function in C-Related End Stage Liver Disease

Background/Aims. Renal impairment is a common complication of cirrhosis. Serum creatinine is less sensitive in these patients. Measurement of the glomerular filtration rate (GFR) is the gold standard but time consuming. The aim is to validate plasma NGAL (pNGAL) and urinary NGAL (uNGAL) as markers of renal function in patients with HCV related cirrhosis.Patient and Methods. One hundred HCV related end stage liver cirrhosis patients were randomized into two groups: Group I (n=35), patients with GFR < 60 mL/m measured by isotope scanning of the kidney (Renogram), and Group II (n=65), patients with GFR ≥ 60 mL/m. The pNGAL and uNGAL were measured within 2 days of the Renogram.Results. Both groups were matched with age, sex, and Child Pugh score. There was statistically significant difference between both groups regarding serum creatinine (1.98 ± 1.04 versus 1.38 ± 0.88 mg/dL;p=0.003) and pNGAL level (5.79 ± 2.06 versus 7.25 ± 3.30 ng/dL;p=0.019). Both groups were comparable (p>0.05) for the uNGAL (6.00 ± 0.78 versus 6.03 ± 0.96 ng/mL). Unlike uNGAL, the pNGAL positively correlated with total GFR by Renogram (r=0.3;p=0.001). With a cutoff ≥4 ng/mL, pNGAL had 94.3% sensitivity and 1.5% specificity and PPV = 34, NPV = 33.3, LR+ = −175.1, and LR− = −60.6.Conclusion. The pNGAL is a promising marker of the renal function in patients with cirrhosis.

Neutrophil Gelatinase-Associated Lipocalin: A New Marker of Renal Function in C-Related End Stage Liver Disease

Background/Aims. Renal impairment is a common complication of cirrhosis. Serum creatinine is less sensitive in these patients. Measurement of the glomerular filtration rate (GFR) is the gold standard but time consuming. The aim is to validate plasma NGAL (pNGAL) and urinary NGAL (uNGAL) as markers of renal function in patients with HCV related cirrhosis.Patient and Methods. One hundred HCV related end stage liver cirrhosis patients were randomized into two groups: Group I (n=35), patients with GFR < 60 mL/m measured by isotope scanning of the kidney (Renogram), and Group II (n=65), patients with GFR ≥ 60 mL/m. The pNGAL and uNGAL were measured within 2 days of the Renogram.Results. Both groups were matched with age, sex, and Child Pugh score. There was statistically significant difference between both groups regarding serum creatinine (1.98 ± 1.04 versus 1.38 ± 0.88 mg/dL;p=0.003) and pNGAL level (5.79 ± 2.06 versus 7.25 ± 3.30 ng/dL;p=0.019). Both groups were comparable (p>0.05) for the uNGAL (6.00 ± 0.78 versus 6.03 ± 0.96 ng/mL). Unlike uNGAL, the pNGAL positively correlated with total GFR by Renogram (r=0.3;p=0.001). With a cutoff ≥4 ng/mL, pNGAL had 94.3% sensitivity and 1.5% specificity and PPV = 34, NPV = 33.3, LR+ = −175.1, and LR− = −60.6.Conclusion. The pNGAL is a promising marker of the renal function in patients with cirrhosis.

Kidney injury in cirrhosis: pathophysiological and therapeutic aspects of hepatorenal syndromes

Acute kidney injury (AKI) is frequent in patients with cirrhosis. AKI and hyponatraemia are major determinants of the poor prognosis in advanced cirrhosis. The hepatorenal syndrome (HRS) denotes a functional and potential reversible impairment of renal function. Type 1 HRS, a special type of AKI, is a rapidly progressive AKI, whereas the renal function in type 2 HRS decreases more slowly. HRS is precipitated by factors such as sepsis that aggravate the effective hypovolaemia in decompensated cirrhosis, by lowering arterial pressure and cardiac output and enhanced sympathetic nervous activity. Therefore, attempts to prevent and treat HRS should seek to improve liver function and to ameliorate arterial hypotension, central hypovolaemia and cardiac output, and to reduce renal vasoconstriction. Ample treatment of HRS is important to prevent further progression and death, but as medical treatment only modestly improves long-term survival, these patients should always be considered for liver transplantation. Hyponatraemia, defined as serum sodium <130 mmol/L, is common in patients with decompensated cirrhosis. From a pathophysiological point of view, hyponatraemia is related to an impairment of renal solute-free water excretion most likely caused by an increased vasopressin secretion. Patients with cirrhosis mainly develop hypervolaemic hyponatraemia. Current evidence does not support routine use of vaptans in the management of hyponatraemia in cirrhosis.

Renal dysfunction in end-stage liver disease and post-liver transplant

Renal dysfunction is a frequent complication in patients with end-stage liver disease awaiting orthotopic liver transplantation and in the post-liver transplant period. Although the stereotypical form of renal dysfunction is the hepatorenal syndrome, other causes of acute kidney injury in this population include prerenal azotemia and acute tubular necrosis. Renal injury in a patient with cirrhosis is associated with a poor prognosis.

Non-hemorrhagic acute complications associated with cirrhosis and portal hypertension

Timely recognition and management of acute complications of cirrhosis is of significant importance in order to reduce morbidity and mortality, especially in the hospitalized patient. In this review, we present a practical approach to the identification and management of non-hemorrhagic acute complications of cirrhosis, specifically bacterial infections, acute kidney injury, and acute exacerbation of hepatic encephalopathy, focusing on patient stratification.