A modified acute kidney injury classification for diagnosis and risk stratification of impairment of kidney function in cirrhosis

Healthcare Resource Utilization and Goals of Care Discussions in Patients with Cirrhosis and Acute Kidney Injury

BACKGROUND

Patients with cirrhosis and acute kidney injury (AKI) are critically ill and have high health care resource utilization (HCRU). The impact and timing of goals of care discussions on HCRU are not well described.

METHODS

221 patients enrolled in a prospective cohort study of patients admitted with AKI and cirrhosis were reviewed. Documentation and timing of a goals of care discussions were analyzed as predictors of HCRU, defined as a composite outcome of intubation, initiation of renal replacement therapy, and/or admission to the intensive care unit.

RESULTS

Median MELD score was 26 [IQR 19, 33]. 29% patients were listed for liver transplant. 90-day mortality was 61%. 51% patients had at least one HCRU episode. Code status changed from admission to discharge from 91%/7%/0% to 68%/14%18% (full code/do not resuscitate/comfort measures, p < 0.001). 28% patients underwent goals of care discussions, with change in code status at a median of 16 [9, 22] days into admission. Only 18% of discussions were within 7 days of admission and all were after an HCRU event. Being listed for liver transplant was not associated with whether goals of care discussions occurred (23% listed vs. 31% non-listed, p = 0.24) but was associated with higher HCRU (69% vs. 43%; p < 0.001).

CONCLUSION

Goals of care discussions occurred late into the hospital course, after episodes of HCRU. Efforts should be made to engage in these discussions earlier in the hospital stay, which may decrease HCRU rates in this critically ill population and align with patients' goals of care.

The hepatocellular carcinoma risk in patients with HBV-related cirrhosis: a competing risk nomogram based on a 4-year retrospective cohort study

Objective

The study aimed to build and validate a competitive risk nomogram to predict the cumulative incidence of hepatocellular carcinoma (HCC) for patients with hepatitis B virus (HBV)-related cirrhosis.

Methods

A total of 1401 HBV-related cirrhosis patients were retrospectively enrolled from January 1, 2011 to December 31, 2014. Application of 20 times imputation dealt with missing data using multiple imputation by chained equations (MICE). The patients were randomly divided into a training set (n = 1017) and a validation set (n = 384) at a ratio of 3:1. A prediction study was carried out using a competing risk model, where the event of interest was HCC and the competing events were death and liver transplantation, and subdistribution hazard ratios (sHRs) with 95% CIs were reported. The multivariate competing risk model was constructed and validated.

Results

There was a negligible difference between the original database and the 20 imputed datasets. At the end of follow-up, the median follow-up time was 69.9 months (interquartile range: 43.8-86.6). There were 31.5% (442/1401) of the patients who developed HCC, with a 5-year cumulative incidence of 22.9 (95%CI, 20.8%-25.2%). The univariate and multivariate competing risk regression and construction of the nomogram were performed in 20 imputed training datasets. Age, sex, antiviral therapy history, hepatitis B e antigen, alcohol drinking history, and alpha-fetoprotein levels were included in the nomogram. The area under receiver operating characteristic curve values at 12, 24, 36, 60, and 96 months were 0.68, 0.69, 0.70, 0.68, and 0.80, and the Brier scores were 0.30, 0.25, 0.23, 0.21, and 0.20 in the validation set. According to the cumulative incidence function, the nomogram effectively screened out high-risk HCC patients from low-risk patients in the presence of competing events (Fine-Gray test p < 0.001).

Conclusion

The competitive risk nomogram was allowed to be used for predicting HCC risk in individual patients with liver cirrhosis, taking into account both the association between risk factors and HCC and the modifying effect of competition events on this association.

Hepatorenal Syndrome in Cirrhosis

Hepatorenal syndrome (HRS) is a form of kidney dysfunction that characteristically occurs in liver cirrhosis. It is characterized by a marked impairment of kidney function in response to circulatory and hemodynamic alterations that occur in advanced stages of liver cirrhosis, aggravated by systemic inflammation and bacterial translocation. The classical definitions of the types of HRS have been recently revisited and 2 forms of HRS have been redefined: the acute form, referred to as acute kidney injury (HRS-AKI), and the chronic form, referred to as chronic kidney disease. HRS-AKI is one of the most severe forms of AKI in patients with cirrhosis and it consists of an abrupt impairment of kidney function, frequently triggered by an infection, appearing in the setting of advanced decompensated cirrhosis. Differential diagnosis with other causes of AKI is crucial because HRS-AKI requires a specific treatment. Differential diagnosis with AKI-acute tubular necrosis may be challenging and kidney biomarkers may be useful in this setting. Treatment of HRS-AKI is based on the administration of vasoconstrictor drugs in combination with volume expansion with albumin. Prognosis of HRS-AKI is poor, and the ideal definitive treatment consists of liver transplantation or simultaneous liver-kidney transplantation. HRS-AKI has a big impact on patients' quality of life. Management of HRS-AKI remains challenging in specific situations such as alcohol-associated hepatitis or metabolic-associated steatotic liver disease cirrhosis. Developing preventive measures for HRS-AKI, improving its early identification, discovering new biomarkers for differential diagnosis, and improving the response to therapy are some of the unmet needs in the field of HRS-AKI.

Prospective validation of the EASL management algorithm for acute kidney injury in cirrhosis

BACKGROUND & AIMS

The management of acute kidney injury (AKI) in cirrhosis is challenging. The EASL guidelines proposed an algorithm for the management of AKI, but this has never been validated. We aimed to prospectively evaluate this algorithm in clinical practice.

METHODS

We performed a prospective cohort study in consecutive hospitalized patients with cirrhosis and AKI. The EASL management algorithm includes identification/treatment of precipitating factors, 2-day albumin infusion in patients with AKI ≥stage 1B, and treatment with terlipressin in patients with hepatorenal syndrome (HRS-AKI). The primary outcome was treatment response, which included both full and partial response. Secondary outcomes were survival and adverse events associated with terlipressin therapy.

RESULTS

A total of 202 AKI episodes in 139 patients were included. Overall treatment response was 80%, while renal replacement therapy was required in only 8%. Response to albumin infusion was achieved in one-third of episodes. Of patients not responding to albumin, most (74%) did not meet the diagnostic criteria of HRS-AKI, with acute tubular necrosis (ATN) being the most common phenotype. The response rate in patients not meeting the criteria for HRS-AKI was 70%. Only 30 patients met the diagnostic criteria for HRS-AKI, and their response rate to terlipressin was 61%. Median time from AKI diagnosis to terlipressin initiation was only 2.5 days. While uNGAL (urinary neutrophil gelatinase-associated lipocalin) could differentiate ATN from other phenotypes (AUROC 0.78), it did not predict response to therapy in HRS-AKI. Ninety-day transplant-free survival was negatively associated with MELD-Na, ATN and HRS-AKI as well as uNGAL. Three patients treated with terlipressin developed pulmonary edema.

CONCLUSIONS

The application of the EASL AKI algorithm is associated with very good response rates and does not significantly delay initiation of terlipressin therapy.

IMPACT AND IMPLICATIONS

The occurrence of acute kidney injury (AKI) in patients with cirrhosis is associated with poor short-term mortality. Improving its rapid identification and prompt management was the focus of the recently proposed EASL AKI algorithm. This is the first prospective study demonstrating that high AKI response rates are achieved with the use of this algorithm, which includes identification of AKI, treatment of precipitating factors, a 2-day albumin challenge in patients with AKI ≥1B, and supportive therapy in patients with persistent AKI not meeting HRS-AKI criteria or terlipressin with albumin in those with HRS-AKI. These findings support the use of this algorithm in clinical practice.

Prognostic significance of acute kidney injury stage 1B in hospitalized patients with cirrhosis: A US nationwide study

Understanding the prognostic significance of acute kidney injury (AKI) stage 1B [serum creatinine (sCr) ≥1.5 mg/dL] compared with stage 1A (sCr < 1.5 mg/dL) in a US population is important as it can impact initial management decisions for AKI in hospitalized cirrhosis patients. Therefore, we aimed to define outcomes associated with stage 1B in a nationwide US cohort of hospitalized cirrhosis patients with AKI. Hospitalized cirrhosis patients with AKI in the Cerner-Health-Facts database from January 2009 to September 2017 (n = 6250) were assessed for AKI stage 1 (≥1.5-2-fold increase in sCr from baseline) and were followed for 90 days for outcomes. The primary outcome was 90-day mortality; secondary outcomes were in-hospital AKI progression and AKI recovery. Competing-risk multivariable analysis was performed to determine the independent association between stage 1B, 90-day mortality (liver transplant as a competing risk), and AKI recovery (death/liver transplant as a competing risk). Multivariable logistic regression analysis was performed to determine the independent association between stage 1B and AKI progression. In all, 4654 patients with stage 1 were analyzed: 1A (44.3%) and 1B (55.7%). Stage 1B patients had a significantly higher cumulative incidence of 90-day mortality compared with stage 1A patients, 27.2% versus 19.7% ( p < 0.001). In multivariable competing-risk analysis, patients with stage 1B (vs. 1A) had a higher risk for mortality at 90 days [sHR 1.52 (95% CI 1.20-1.92), p = 0.001] and decreased probability for AKI recovery [sHR 0.76 (95% CI 0.69-0.83), p < 0.001]. Furthermore, in multivariable logistic regression analysis, AKI stage 1B (vs. 1A) was independently associated with AKI progression, OR 1.42 (95% CI 1.14-1.72) ( p < 0.001). AKI stage 1B patients have a significantly higher risk for 90-day mortality, AKI progression, and reduced probability of AKI recovery compared with AKI stage 1A patients. These results could guide initial management decisions for AKI in hospitalized patients with cirrhosis.

In severe alcohol-related hepatitis, acute kidney injury is prevalent, associated with mortality independent of liver disease severity, and can be predicted using IL-8 and micro-RNAs

BACKGROUND

The prevalence, prediction and impact of acute kidney injury (AKI) in alcohol-related hepatitis (AH) is uncertain.

AIMS

We aimed to determine AKI incidence; association with mortality; evaluate serum biomarkers and the modifying effects of prednisolone and pentoxifylline in the largest AH cohort to date.

METHODS

Participants in the Steroids or Pentoxifylline for Alcoholic Hepatitis trial with day zero (D0) creatinine available were included. AKI was defined by modified International Club of Ascites criteria; incident AKI as day 7 (D7) AKI without D0-AKI. Survival was compared by Kaplan-Meier; mortality associations by Cox regression; associations with AKI by binary logistic regression; biomarkers by AUROC analyses.

RESULTS

D0-AKI was present in 198/1051 (19%) participants; incident AKI developed in a further 119/571 (21%) with available data. Participants with D0-AKI had higher 90-day mortality than those without (32% vs. 25%, p = 0.008), as did participants with incident AKI compared to those without D0-AKI or incident AKI (47% vs. 25%, p < 0.001). Incident AKI was associated with D90 mortality adjusted for age and discriminant function (AHR 2.15, 1.56-2.97, p < 0.001); D0-AKI was not. Prednisolone therapy reduced incident AKI (AOR 0.55, 0.36-0.85, p = 0.007) but not mortality. D0 bilirubin and IL-8 combined, miR-6826-5p, and miR-6811-3p predicted incident AKI (AUROCs 0.726, 0.821, 0.770, p < 0.01).

CONCLUSIONS

Incident AKI is associated with 90-day mortality independent of liver function. Prednisolone therapy was associated with reduced incident AKI. IL-8 and several miRNAs are potential biomarkers to predict AKI. Novel therapies to prevent incident AKI should be evaluated in AH to reduce mortality.

Incidence and outcomes of acute kidney injury including hepatorenal syndrome in hospitalized patients with cirrhosis in the US

BACKGROUND & AIMS

Acute kidney injury (AKI) in cirrhosis is common and associated with high morbidity, but the incidence rates of different etiologies of AKI are not well described in the US. We compared incidence rates, practice patterns, and outcomes across etiologies of AKI in cirrhosis.

METHODS

We performed a retrospective cohort study of 11 hospital networks, including consecutive adult patients admitted with AKI and cirrhosis in 2019. The etiology of AKI was adjudicated based on pre-specified clinical definitions (prerenal/hypovolemic AKI, hepatorenal syndrome [HRS-AKI], acute tubular necrosis [ATN], other).

RESULTS

A total of 2,063 patients were included (median age 62 [IQR 54-69] years, 38.3% female, median MELD-Na score 26 [19-31]). The most common etiology was prerenal AKI (44.3%), followed by ATN (30.4%) and HRS-AKI (12.1%); 6.0% had other AKI, and 7.2% could not be classified. In our cohort, 8.1% of patients received a liver transplant and 36.5% died by 90 days. The lowest rate of death was observed in patients with prerenal AKI (22.2%; p <0.001), while death rates were higher but not significantly different from each other in those with HRS-AKI and ATN (49.0% vs. 52.7%; p = 0.42). Using prerenal AKI as a reference, the adjusted subdistribution hazard ratio (sHR) for 90-day mortality was higher for HRS-AKI (sHR 2.78; 95% CI 2.18-3.54; p <0.001) and ATN (sHR 2.83; 95% CI 2.36-3.41; p <0.001). In adjusted analysis, higher AKI stage and lack of complete response to treatment were associated with an increased risk of 90-day mortality (p <0.001 for all).

CONCLUSION

AKI is a severe complication of cirrhosis. HRS-AKI is uncommon and is associated with similar outcomes to ATN. The etiology of AKI, AKI stage/severity, and non-response to treatment were associated with mortality. Further optimization of vasoconstrictors for HRS-AKI and supportive therapies for ATN are needed.

IMPACT AND IMPLICATIONS

Acute kidney injury (AKI) in cirrhosis carries high morbidity, and management is determined by the etiology of injury. However, a large and well-adjudicated multicenter database from US centers that uses updated AKI definitions is lacking. Our findings demonstrate that acute tubular necrosis and hepatorenal syndrome have similar outcomes (∼50% mortality at 90 days), though hepatorenal syndrome is uncommon (12% of all AKI cases). These findings represent practice patterns at US transplant/tertiary centers and can be used as a baseline, presenting the situation prior to the adoption of terlipressin in the US.

[Hepatorenal Syndrome]

Hepatorenal syndrome (HRS) is a critical and potentially life-threatening complication of advanced liver disease, including cirrhosis. It is characterized by the development of renal dysfunction in the absence of underlying structural kidney pathology. The pathophysiology of HRS involves complex interactions between systemic and renal hemodynamics, neurohormonal imbalances, and the intricate role of vasoconstrictor substances. Understanding these mechanisms is crucial for the timely identification and management of HRS. The diagnosis of HRS is primarily clinical and relies on specific criteria that consider the exclusion of other causes of renal dysfunction. The management of HRS comprises two main approaches: vasoconstrictor therapy and albumin infusion, which aim to improve renal perfusion and mitigate the hyperdynamic circulation often seen in advanced liver disease. Additionally, strategies such as liver transplantation and renal replacement therapy are essential considerations based on individual patient characteristics and disease severity. This review article provides a comprehensive overview of hepatorenal syndrome, focusing on its pathophysiology, diagnostic criteria, and current management strategies.

Hepatorenal syndrome: Current concepts and future perspectives

Hepatorenal syndrome (HRS), a progressive but potentially reversible deterioration of kidney function, remains a major complication in patients with advanced cirrhosis, often leading to death before liver transplantation (LT). Recent updates in the pathophysiology, definition, and classification of HRS have led to a complete revision of the nomenclature and diagnostic criteria for HRS type 1, which was renamed HRS-acute kidney injury (AKI). HRS is characterized by severe impairment of kidney function due to increased splanchnic blood flow, activation of several vasoconstriction factors, severe vasoconstriction of the renal arteries in the absence of kidney histologic abnormalities, nitric oxide dysfunction, and systemic inflammation. Diagnosis of HRS remains a challenge because of the lack of specific diagnostic biomarkers that accurately distinguishes structural from functional AKI, and mainly involves the differential diagnosis from other forms of AKI, particularly acute tubular necrosis. The optimal treatment of HRS is LT. While awaiting LT, treatment options include vasoconstrictor drugs to counteract splanchnic arterial vasodilation and plasma volume expansion by intravenous albumin infusion. In patients with HRS unresponsive to pharmacological treatment and with conventional indications for kidney replacement therapy (KRT), such as volume overload, uremia, or electrolyte imbalances, KRT may be applied as a bridging therapy to transplantation. Other interventions, such as transjugular intrahepatic portosystemic shunt, and artificial liver support systems have a very limited role in improving outcomes in HRS. Although recently developed novel therapies have potential to improve outcomes of patients with HRS, further studies are warranted to validate the efficacy of these novel agents.

Acute Kidney Injury in Liver Cirrhosis

Acute kidney injury (AKI) is common in cirrhotic patients affecting almost 20% of these patients. While multiple etiologies can lead to AKI, pre-renal azotemia seems to be the most common cause of AKI. Irrespective of the cause, AKI is associated with worse survival with the poorest outcomes observed in those with hepatorenal syndrome (HRS) and acute tubular necrosis (ATN). In recent years, new definitions, and classifications of AKI in cirrhosis have emerged. More knowledge has also become available regarding the benefits and drawbacks of albumin and terlipressin use in these patients. Diagnostic tools such as urinary biomarkers and point-of-care ultrasound (POCUS) became available and they will be used in the near future to differentiate between different causes of AKI and direct management of AKI in these patients. In this update, we will review these new classifications, treatment recommendations, and diagnostic tools for AKI in cirrhotic patients.

Neutrophil gelatinase-associated lipocalin predicts the efficacy of tolvaptan for ascites in patients with liver cirrhosis

BACKGROUND

Acute kidney injury (AKI) is associated with liver cirrhosis (LC), water retention, diuretics to treat water retention, and a poor prognosis. Urinary neutrophil gelatinase-associated lipocalin (uNGAL) reportedly predicts a poor prognosis in decompensated LC. This study investigated the usefulness of uNGAL in predicting the short- and long-term effects of tolvaptan (TVP) and the incidence of AKI post-TVP administration.

METHODS

Of the LC cases with water retention, 86 with available pre-treatment uNGAL were analyzed. A short-term response was defined as weight loss of ≥ 1.5 kg within the first week; a long-term response was defined as a short-term response without early recurrence. The uNGAL usefulness in predicting the short- and long-term effects of TVP and AKI incidence post-TVP administration was investigated.

RESULTS

Short-term effects of TVP were observed in 52 patients. Of these, 15 patients had an early recurrence. In multivariate analysis, significant short-term predictive factors were C-reactive protein (CRP) < 1.4 mg/dl, uNa/K ratio ≥ 3.51, and uNGAL < 50.2 ng/ml. Patients were classified according to these three cut-off values, with short-term response rates of 92.9%, 68.8%, 26.7%, and 0% for 0, 1, 2, and 3 points, respectively. CRP < 0.94 mg/dl and uNGAL < 50.2 ng/ml were significant factors for predicting the long-term response of TVP. The AKI incidence post-TVP was 8.1% (n = 7) and was significantly higher among those with uNGAL ≥ 38.1 ng/mL.

CONCLUSION

uNGAL is a useful predictor of the short- and long-term efficacy of TVP and can be useful in predicting AKI incidence post-TVP administration.

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.

Essentials of Liver Transplantation in the Setting of Acute Kidney Injury and Chronic Kidney Disease

Kidney dysfunction is common among liver transplant candidates with decompensated cirrhosis and has a major impact on pre- and post-liver transplant survival. Updated definitions of acute kidney injury and criteria for the diagnosis of hepatorenal syndrome allow for early recognition and intervention, including early initiation of vasoconstrictor therapy for hepatorenal syndrome. The rise of the metabolic syndrome and nonalcoholic fatty liver disease as a cause of cirrhosis has coincided with an increase in intrinsic chronic kidney disease recognized in transplant candidates and recipients. Ultimately, the ability to accurately assess kidney function and associated risk is essential to decision-making in the context of transplantation, including selection of candidates for simultaneous liver and kidney transplantation.

Diagnostic and prognostic performance of urinary neutrophil gelatinase-associated lipocalin in patients with cirrhosis and acute kidney injury

BACKGROUND AND AIMS

Acute kidney injury (AKI) commonly occurs in patients with decompensated cirrhosis. Urinary neutrophil gelatinase-associated lipocalin (uNGAL) could help discriminate between different etiologies of AKI. The aim of this study was to investigate the use of uNGAL in (1) the differential diagnosis of AKI, (2) predicting the response to terlipressin and albumin in patients with hepatorenal syndrome-AKI (HRS-AKI), and (3) predicting in-hospital mortality in patients with AKI.

APPROACH AND RESULTS

One hundred sixty-two consecutive patients with cirrhosis and AKI were included from 2015 to 2020 and followed until transplant, death, or 90 days. Standard urinary markers and uNGAL were measured. Data on treatment, type, and resolution of AKI were collected. Thirty-five patients (21.6%) had prerenal AKI, 64 (39.5%) HRS-AKI, 27 (16.7%) acute tubular necrosis-AKI (ATN-AKI), and 36 (22.2%) a mixed form of AKI. Mean values of uNGAL were significantly higher in ATN-AKI than in other types of AKI (1162 ng/ml [95% CI 423-2105 ng/ml] vs. 109 ng/ml [95% CI 52-192 ng/ml]; p  < 0.001). uNGAL showed a high discrimination ability in predicting ATN-AKI (area under the receiver operating characteristic curve, 0.854; 95% CI 0.767-0.941; p  < 0.001). The best-performing threshold was found to be 220 ng/ml (sensitivity, 89%; specificity, 78%). The same threshold was independently associated with a higher risk of nonresponse (adjusted OR [aOR], 6.17; 95% CI 1.41-27.03; p  = 0.016). In multivariable analysis (adjusted for age, Model for End-Stage Liver Disease, acute-on-chronic liver failure, leukocytes, and type of AKI), uNGAL was an independent predictor of in-hospital mortality (aOR, 1.74; 95% CI 1.26-2.38; p  = 0.001).

CONCLUSIONS

uNGAL is an adequate biomarker for making a differential diagnosis of AKI in cirrhosis and predicting the response to terlipressin and albumin in patients with HRS-AKI. In addition, it is an independent predictor of in-hospital mortality.

Acute kidney injury in patients with acute-on-chronic liver failure: clinical significance and management

Acute-on-chronic-liver failure (ACLF) refers to a phenomenon in which patients with chronic liver disease develop multiple organ failure due to acute exacerbation of underlying liver disease. More than 10 definitions of ACLF are extant around the world, and there is lack of consensus on whether extrahepatic organ failure is a main component or a consequence of ACLF. Asian and European consortiums have their own definitions of ACLF. The Asian Pacific Association for the Study of the Liver ACLF Research Consortium does not consider kidney failure as a diagnostic criterion for ACLF. Meanwhile, the European Association for the Study of the Liver Chronic Liver Failure and the North American Consortium for the Study of End-stage Liver Disease do consider kidney failure as an important factor in diagnosing and assessing the severity of ACLF. When kidney failure occurs in ACLF patients, treatment varies depending on the presence and stage of acute kidney injury (AKI). In general, the diagnosis of AKI in cirrhotic patients is based on the International Club of Ascites criteria: an increase of 0.3 mg/dL or more within 48 hours or a serum creatinine increase of 50% or more within one week. This study underscores the importance of kidney failure or AKI in patients with ACLF by reviewing its pathophysiology, prevention methods, and treatment approaches.

Urine neutrophil gelatinase-associated lipocalin as a biomarker of acute kidney injury and prognosis in decompensated chronic liver disease: A prospective study

BACKGROUND

Acute kidney injury (AKI) heralds deterioration in patients with decompensated chronic liver disease (DCLD). Serum creatinine (sCr), a component of the model for end-stage liver disease-sodium (MELD-Na) prognostic score, has limitations in patients with DCLD. We evaluated the prognostic role of urine neutrophil gelatinase-associated lipocalin (NGAL) in DCLD and its ability to sub-type AKI.

METHODS

Total 147 consecutive patients hospitalized between June 2018 and June 2020 for complications of DCLD were evaluated. Urine NGAL was estimated and demographic, clinical and biochemical parameters recorded at baseline. Participants were followed up till the end of study period or mortality, whichever came earlier. Primary outcomes included all-cause mortality and time to death after index hospitalization. Secondary outcomes included the presence and type of AKI, need for intensive care unit (ICU) stay, length of ICU/hospital stay, in-hospital mortality, development of new-onset/recurrent AKI and recurrent hospitalization after index admission.

RESULTS

Urine NGAL was highest in acute tubular necrosis (ATN), lowest in pre-renal azotemia (PRA) and intermediate in hepatorenal syndrome (HRS-AKI). Urine NGAL (p = 0.0208) was superior to sCr (p = 0.0388) and inferior to fractionated excretion of sodium (FENa) (p = 0.0013) in stratifying AKI. A cut-off of 203.9 ng/mL discriminated between HRS and PRA with sensitivity 77.8% and specificity 68.7%. Urine NGAL correlated with MELD-Na score, need for ICU stay, in-hospital mortality and mortality at three and six months. Two-year survival was significantly lower in patients with urine NGAL > 205 ng/mL. Addition of log-urine-NGAL score did not improve predictive performance of MELD-Na.

CONCLUSION

Urine NGAL could identify AKI sub-types and correlated with short-term clinical outcomes, including mortality.

Renal Insufficiency in Patients with Cirrhosis

Renal failure is one of the most prevalent complications in patients with cirrhosis and is of the utmost prognostic relevance. Acute kidney injury (AKI) in cirrhosis results from a spectrum of etiologies, of which hepatorenal syndrome (HRS) carries the worst prognosis. Correct differentiation of the etiology of AKI in cirrhosis is imperative, as treatment defers substantially. This review summarizes the current diagnostic criteria, pathophysiology, diagnosis, and therapeutic concepts for AKI and HRS-AKI in cirrhosis.

Distinct Subtypes of Hepatorenal Syndrome and Associated Outcomes as Identified by Machine Learning Consensus Clustering

BACKGROUND

The utilization of multi-dimensional patient data to subtype hepatorenal syndrome (HRS) can individualize patient care. Machine learning (ML) consensus clustering may identify HRS subgroups with unique clinical profiles. In this study, we aim to identify clinically meaningful clusters of hospitalized patients for HRS using an unsupervised ML clustering approach.

METHODS

Consensus clustering analysis was performed based on patient characteristics in 5564 patients primarily admitted for HRS in the National Inpatient Sample from 2003-2014 to identify clinically distinct HRS subgroups. We applied standardized mean difference to evaluate key subgroup features, and compared in-hospital mortality between assigned clusters.

RESULTS

The algorithm revealed four best distinct HRS subgroups based on patient characteristics. Cluster 1 patients (n = 1617) were older, and more likely to have non-alcoholic fatty liver disease, cardiovascular comorbidities, hypertension, and diabetes. Cluster 2 patients (n = 1577) were younger and more likely to have hepatitis C, and less likely to have acute liver failure. Cluster 3 patients (n = 642) were younger, and more likely to have non-elective admission, acetaminophen overdose, acute liver failure, to develop in-hospital medical complications and organ system failure, and to require supporting therapies, including renal replacement therapy, and mechanical ventilation. Cluster 4 patients (n = 1728) were younger, and more likely to have alcoholic cirrhosis and to smoke. Thirty-three percent of patients died in hospital. In-hospital mortality was higher in cluster 1 (OR 1.53; 95% CI 1.31-1.79) and cluster 3 (OR 7.03; 95% CI 5.73-8.62), compared to cluster 2, while cluster 4 had comparable in-hospital mortality (OR 1.13; 95% CI 0.97-1.32).

CONCLUSIONS

Consensus clustering analysis provides the pattern of clinical characteristics and clinically distinct HRS phenotypes with different outcomes.

Application of CT contrast medium is not associated with an increased risk for acute kidney injury in patients with decompensated cirrhosis

BACKGROUND

Acute kidney injury (AKI) is a frequent complication in patients with decompensated cirrhosis. Studies reported conflicting results regarding the nephrotoxic potential of iodinated contrast medium (CM) for computer tomography (CT).

AIM

To investigate the impact of diagnostic CM application on kidney function in patients with decompensated cirrhosis.

METHODS

First, we evaluated the impact of diagnostic CM-CT on AKI incidence in a cross-sectional approach. Second, we analysed 28-day AKI incidence post-CM-CT in patients with impaired kidney function (i.e., creatinine >133 μmoL/L). Third, we excluded all patients with relevant interventions besides CM-CT. All remaining patients were matched via propensity score matching (PPSM) and further analysed. Last, we validated the results in an independent dataset of prospectively collected registry data of 118 patients with decompensated cirrhosis. Here, plasma samples were analysed regarding neutrophil-gelatinase-associated-lipocalin (NGAL).

RESULTS

Of the 611 included patients, 98 (16%) received CM-CT. CM-CT was not associated with AKI in the cross-sectional approach (CM-CT:8% vs. no CM-CT:15%; p = 0.08). Furthermore, CM-CT was not associated with higher 28-day AKI incidence among patients with impaired kidney function (HR:0.79; 95% CI 0.45-1.38; p = 0.40). The PPSM cohort revealed no association between CM-CT and AKI or severe AKI (HR:1.28, p = 0.45 and HR:1.62; p = 0.43). Moreover, CM-CT did not result in worsening of kidney function after CM application. In the validation cohort, CM-CT was also not linked to AKI (p = 0.85) and NGAL levels were not increased in those with CM-CT (CM-CT:309 ng/ml vs. No CM-CT:266 ng/ml, p = 0.35).

CONCLUSION

Decompensated cirrhosis per se should not preclude diagnostic CM-CT.

Novel biomarkers of acute kidney injury in chronic liver disease: Where do we stand after a decade of research?

Acute kidney injury (AKI) is a frequently encountered complication in decompensated chronic liver disease (CLD) with an estimated prevalence of 20%-50% among hospitalized patients. AKI often heralds the onset of a downhill course in the natural history of CLD. Serum creatinine has several limitations as a stand-alone marker of AKI in patients with decompensated CLD. The concept of hepatorenal syndrome, the prototype of AKI in decompensated CLD, has evolved tremendously over recent years. There is emerging evidence of an additional "structural" component in the pathophysiology of hepatorenal syndrome-AKI, which was previously identified as a purely "functional" form of renal impairment. Lacunae in the existent biochemical arsenal for diagnosis and prognosis of AKI have fueled enthusiastic research in the field of novel biomarkers of kidney injury in patients with cirrhosis. The advent of these biomarkers provides a crucial window of opportunity to improve the diagnosis and clinical outcomes of this vulnerable cohort of patients. This review summarizes the dynamic concept of renal dysfunction in CLD and the available literature on the role of novel biomarkers of AKI in assessing renal function, identifying AKI subtypes, and predicting prognosis. There is special emphasis on the renal tubular injury marker, neutrophil gelatinase-associated lipocalin, the most exhaustively studied biomarker of AKI in the CLD population.

Impact of acute kidney injury on the risk of mortality in patients with cirrhosis: a systematic review and meta-analysis

Objective

To compare the risk of mortality in patients with cirrhosis with and without the associated acute kidney injury (AKI).

Methods

We performed a systematic search in the PubMed, Embase, and Scopus databases for observational studies that were done on patients with cirrhosis. Eligible studies reported AKI in patients with cirrhosis and compared mortality among patients with and without AKI. We used a random-effects model, using STATA version 16.0, for deriving pooled effect sizes that were reported as odds ratio (OR) with 95% confidence intervals (CIs).

Results

Thirty-two studies were included. In patients with cirrhosis, AKI was significantly associated with higher in-hospital mortality (OR 5.92), and mortality at 30 days (OR 4.78), 90 days (OR 4.34), and at 1 year follow-up (OR 4.82) compared to patients without AKI.

Conclusions

AKI is associated with an increased risk of mortality in patients with cirrhosis. Careful monitoring to identify the development of AKI and early prompt management is necessary.

Natural history, spectrum and outcome of stage 3 AKI in patients with acute-on-chronic liver failure

BACKGROUND AND AIM

There is limited data on natural course and interventions in stage-3 acute kidney injury (AKI-3) in patients with acute-on-chronic liver failure (ACLF). We studied the factors of AKI-3 reversal and outcomes of dialysis in ACLF patients.

METHODS

Consecutive patients with ACLF were prospectively enrolled (n = 1022) and variables determining AKI and its outcomes were analysed.

RESULTS

At 1 month, 337 (33%) patients had AKI-3, of which, 131 had AKI-3 at enrolment and 206 developed AKI-3 during hospital stay. Of patients with AKI-3 at enrolment, 18% showed terlipressin response, 21% had AKI resolution and 59% required dialysis. High MELD (≥35) (model 1), serum bilirubin (≥23 mg/dL) (model 2) and AARC score (≥11) (model 3) were independent risk factors for dialysis. Dialysis was associated with worse survival in all AKI patients but improved outcomes in patients with AKI-3 (p = .022, HR 0.69 [0.50-0.95]). Post-mortem kidney biopsies (n = 61) revealed cholemic nephropathy (CN) in 54%, acute tubular necrosis (ATN) in 31%, and a combination (CN and ATN) in 15%. Serum bilirubin was significantly higher in patients with CN, CN and ATN compared with ATN respectively ([30.8 ± 12.2] vs. [26.7 ± 12.0] vs. [18.5 ± 9.8]; p = .002).

CONCLUSION

AKI-3 rapidly increases from 13% to 33% within 30 days in ACLF patients. Histopathological data suggested cholemic nephropathy as the predominant cause which correlated with high bilirubin levels. AKI-3 resolves in only one in five patients. Patients with AARC grade 3 and MELD >35 demand need for early dialysis in AKI-3 for improved outcomes.

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.

Novel Biomarkers of AKI in Cirrhosis

Acute kidney injury (AKI) is a frequent complication in patients with cirrhosis that is associated with poor outcomes and decreased survival. The definition of AKI in cirrhosis is currently based on changes of serum creatinine levels with respect to baseline values. Differential diagnosis of the causes of AKI is of major relevance, considering that some causes of AKI, such as hepatorenal syndrome, have specific treatment options and different prognosis. Prediction of kidney function recovery and patients' survival is also crucial in this patient population to guide clinical decisions. AKI biomarkers in cirrhosis have emerged as a promising tool for differential diagnosis and prognosis in this situation. There are consistent data showing that some urine biomarkers, particularly neutrophil gelatinase-associated lipocalin, may be useful in daily clinical practice for the differential diagnosis of the cause of AKI in cirrhosis. AKI biomarkers may constitute a useful tool for use in differential diagnosis, prognosis of renal function, and survival in patients with cirrhosis. This review focuses on the current state of knowledge and future perspective of novel biomarkers of AKI in cirrhosis.

Assessment of glomerular filtration rate in patients with cirrhosis: Available tools and perspectives

Renal dysfunction often complicates the course of liver disease, resulting in higher morbidity and mortality. The accurate assessment of kidney function in these patients is essential to early identify, stage and treat renal impairment as well as to better predict the prognosis, prioritize the patients for liver transplantation and decide whether to opt for simultaneous liver-kidney transplants. This review analyses the available tools for direct or indirect assessment of glomerular filtration rate, focusing on the flaws and strengths of each method in the specific setting of cirrhosis. The aim is to deliver a clear-cut view on this complex issue, trying to point out which strategies to prefer in this context, especially in the peculiar setting of liver transplantation. Moreover, a glance is given at future promising tools for glomerular filtration rate assessment, including new biomarkers and new equations specifically modelled for the cirrhotic population.

Albumin administration in patients with cirrhosis: Current role and novel perspectives

Mortality in cirrhosis is mostly associated with the development of clinical decompensation, characterized by ascites, hepatic encephalopathy, variceal bleeding, or jaundice. Therefore, it is important to prevent and manage such complications. Traditionally, the pathophysiology of decompensated cirrhosis was explained by the peripheral arterial vasodilation hypothesis, but it is currently understood that decompensation might also be driven by a systemic inflammatory state (the systemic inflammation hypothesis). Considering its oncotic and nononcotic properties, albumin has been thoroughly evaluated in the prevention and management of several of these decompensating events. There are formal evidence-based recommendations from international medical societies proposing that albumin be administered in individuals with cirrhosis undergoing large-volume paracentesis, patients with spontaneous bacterial peritonitis, those with acute kidney injury (even before the etiological diagnosis), and those with hepatorenal syndrome. Moreover, there are a few randomized controlled trials and meta-analyses suggesting a possible role for albumin infusion in patients with cirrhosis and ascites (long-term albumin administration), individuals with hepatic encephalopathy, and those with acute-on-chronic liver failure undergoing modest-volume paracentesis. Further studies are necessary to elucidate whether albumin administration also benefits patients with cirrhosis and other complications, such as individuals with extraperitoneal infections, those hospitalized with decompensated cirrhosis and hypoalbuminemia, and patients with hyponatremia.

Development and validation of a nomogram for predicting overall survival in cirrhotic patients with acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is a common and severe complication in patients with cirrhosis, and is associated with poor prognosis. Therefore, identifying cirrhotic patients with AKI who are at high risk of mortality is very important and may be helpful for providing timely medical interventions to improve the prognosis of these patients. However, studies focused on investigating the risk factors for the mortality of cirrhotic patients with AKI were scarce.

AIM

To identify risk factors for mortality and establish a nomogram for predicting the prognosis of these patients.

METHODS

Two hundred fifty consecutive patients with cirrhosis and AKI were recruited and randomly divided into training cohort (n = 173) and validation cohort (n = 77). In the training cohort, potential risk factors for death were identified by performing a Cox regression analysis, and a nomogram was established. The predictive performance of the nomogram was internally and externally validated by calculating the area under the receiver operating characteristic curve (AUROC), constructing a calibration curve and performing decision curve analysis.

RESULTS

The serum sodium level, international normalized ratio, peak serum creatinine level > 1.5 mg/dL, the presence of hepatic encephalopathy and diabetes were potential risk factors for mortality of cirrhotic patients with AKI in the training dataset. A prognostic nomogram incorporating these variables was established for predicting the overall survival of these patients. Compared with Child-Turcotte-Pugh, the model for end-stage liver disease (MELD) and the MELD-Na scores, the nomogram in predicting 90- and 180-d mortality exhibited better discriminatory power with AUROCs of 0.792 and 0.801 for the training dataset and 0.817 and 0.862 for the validation dataset, respectively. With a nomogram score of 98, patients were divided into low- and high-risk groups, and high-risk patients had a higher mortality rate.

CONCLUSION

A prognostic nomogram displayed good performance for predicting the overall survival of cirrhotic patients with AKI, and will assist clinicians in evaluating the prognosis of these patients.

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.

Frailty as Tested by the Clinical Frailty Scale Is a Risk Factor for Hepatorenal Syndrome in Patients With Liver Cirrhosis

INTRODUCTION

Frailty is common in patients with cirrhosis and increases the vulnerability to internal and external stressors. This study aimed to investigate the impact of frailty, as defined by the Clinical Frailty Scale (CFS), on the risk of acute kidney injury (AKI) and hepatorenal syndrome (HRS-AKI) in hospitalized patients with liver cirrhosis.

METHODS

We analyzed data of 201 nonelectively hospitalized patients with cirrhosis and without higher-grade chronic kidney disease. Patient characteristics were captured within the first 24 hours of hospital admission, and frailty was assessed using the CFS. Patients were followed for the development of AKI and/or HRS-AKI during the hospital stay.

RESULTS

In the total cohort, median CFS was 3 (interquartile range 3-4), and 34 (16.9%) patients were frail (CFS >4). During the hospital stay, 110 (54.7%) and 49 (24.3%) patients developed AKI or HRS-AKI, respectively. Patients with AKI or HRS-AKI had a significantly higher CFS than patients without kidney injury (P < 0.001 each). In multivariable analyses, a higher CFS was independently associated with the development of AKI (odds ratio [OR] 1.467, 95% confidence interval (CI) 1.065-2.021) in the total cohort and HRS-AKI (OR 1.809, 95% CI 1.263-2.591) in the subcohort of patients with a history of ascites. In addition, there was a strong association between frailty (OR 3.717, 95% CI 1.456-9.491) and HRS-AKI.

DISCUSSION

Frailty in patients with cirrhosis is associated with AKI and HRS-AKI. In this context, CFS appears to be a reliable tool to identify patients at high risk for developing AKI or HRS-AKI on hospital admission.

Prognostic Nomograms for Hospital Survival and Transplant-Free Survival of Patients with Hepatorenal Syndrome: A Retrospective Cohort Study

Hepatorenal syndrome (HRS) is a life-threatening complication of cirrhosis with a poor prognosis. To develop novel and effective nomograms which could numerically predict both the hospital survival and transplant-free survival of HRS, we retrospectively enrolled a cohort of 149 patients. A backward stepwise method based on the smallest Akaike information criterion value was applied to select the covariates to be included in the Cox proportional hazards models. The Harrell C-index, area under the receiver operating characteristic curve (AUC), Brier score, and Kaplan–Meier curves with the log-rank test were used to assess nomograms. The bootstrapping method with 1000 resamples was performed for internal validation. The nomogram predicting hospital survival included prothrombin activity, HRS clinical pattern, Child–Pugh class, and baseline serum creatinine. The C-index was 0.72 (95% confidence interval (CI), 0.65–0.78), and the adjusted C-index was 0.72 (95% CI, 0.66–0.79). The nomogram predicting transplant-free survival included sex, prothrombin activity, HRS clinical pattern, model for end-stage liver disease–Na score, and peak serum creatinine. The C-index of the nomogram was 0.74 (95% CI, 0.69–0.79), and the adjusted C-index was 0.74 (95% CI, 0.68–0.79). The AUC and Brier score at 15, 30, and 45 days calculated from the hospital survival nomogram and those at 6, 12, and 18 months calculated from the transplant-free survival nomogram revealed good predictive ability. The two models can be used to identify patients at high risk of HRS and promote early intervention treatment.

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.

Acute kidney injury in patients with cirrhosis: Prospective longitudinal study in 405 patients

BACKGROUND

Acute kidney injury (AKI) is common in patients with cirrhosis. In 2015, the International Club of Ascites (ICA) proposed new definitions of AKI in order to improve the prediction of outcomes. Our aim was to assess the prevalence and prognostic value of ICA 2015 - AKI criteria in hospitalised patients with cirrhosis.

METHODS

We prospectively collected data from 405 consecutive cirrhotic patients admitted to the hospital between November 2016 and November 2017. AKI was diagnosed at inclusion according to ICA 2015 criteria, and was assessed to predict 30-day and 90-day in-hospital mortality.

RESULTS

AKI was diagnosed in 78 (19.3%) patients. AKI was independently associated with 90-day death (HR 7.61; 95% CI 4.75-12.19; p < 0.001). In hospital, 30-day and 90-day survival was lower in the group of patients with AKI compared to the group with no AKI (72% vs. 98%, p < 0.001; 64% vs. 96%, p < 0.001; and 49% vs. 81%, p < 0.001, respectively). Patients with stage 1a AKI had a lower 30-day and 90-day survival compared to the group of patients who did not develop AKI (71% vs. 96%, p < 0.001, and 71% vs. 91%, p < 0.01, respectively) and better survival than patients with more severe AKI (71% vs. 40%, p < 0.01).

CONCLUSIONS

AKI was independently associated with mortality in patients with cirrhosis, even at the very early 1a stage. Response to treatment improved survival, and was inversely proportional to the stage of AKI, which suggests that treatment should be started at the earliest stage of AKI.

Prognostic Impact of Early Recovering Acute Kidney Injury Following Liver Transplantation: A Multicenter Retrospective Study

BACKGROUND

Acute kidney injury (AKI) is a common complication after liver transplantation (LT), but the specific impact of rapidly resolving AKI is not elucidated. This study investigates the factors associated with early recovery from AKI and its association with post-LT outcomes.

METHODS

Retrospective analysis of 441 liver transplant recipients with end-stage liver disease without pretransplant renal impairment. AKI was defined according to Kidney Disease Improving Global Outcomes criteria and early renal recovery by its disappearance within 7 d post-LT.

RESULTS

One hundred forty-six patients (32%) developed a post-LT AKI, of whom 99 (69%) recovered early and 45 (31%) did not. Factors associated with early recovery were Kidney Disease Improving Global Outcomes stage 1 (odds ratio [OR],14.11; 95% confidence interval [CI], 5.59-40.22; P < 0.0001), minimum prothrombin time >50 % (OR, 4.50; 95% CI, 1.67-13.46; P = 0.003) and aspartate aminotransferase peak value <1000 U/L (OR, 4.07; 95% CI, 1.64-10.75; P = 0.002) within 48 h post-LT. Patients with early recovery had a renal prognosis similar to that of patients without AKI with no difference in estimated glomerular filtration rate between day 7 and 1 y. Their relative risk of developing chronic kidney disease was 0.88 (95% CI, 0.55-1.41; P = 0.6) with survival identical to patients without AKI and better than patients without early recovery (P < 0.0001).

CONCLUSIONS

Most patients with post-LT AKI recover early and have a similar renal prognosis and survival to those without post-LT AKI. Factors associated with early renal recovery are related to the stage of AKI, the extent of liver injury, and the early graft function. Patients at risk of not recovering may benefit the most from perioperative protective strategies, particularly those aimed at minimizing the adverse effects of calcineurin inhibitors.

An Integrated Review of the Hepatorenal Syndrome

Among the complications of cirrhosis, hepatorenal syndrome (HRS) is characterized by having the worst survival rate. HRS is a disorder that involves the deterioration of kidney function caused primarily by a systemic circulatory dysfunction, but in recent years, systemic inflammation and cirrhotic cardiomyopathy have been discovered to also play an important role. The diagnosis of HRS requires to meet the new International Club of Ascites-Acute Kidney Injury (ICA-AKI) and Hepatorenal Syndrome-Acute Kidney Injury (HRS-AKI) criteria after ruling out other causes of kidney injury. At the time of diagnosis, it is important to start the medical treatment as soon as possible where three types of vasoconstrictors have been recognized: vasopressin analogs (ornipressin and terlipressin), alpha-adrenergic agonists (norepinephrine and midodrine) and somatostatin analogues (octreotide); all should be combined with albumin infusion. Among them, terlipressin and albumin are the first lines of treatment in most cases, although terlipressin should be monitor closely due to its adverse events. The best treatment of choice is a liver transplant, because it is the only definitive treatment for this disease.

In-hospital mortality of hepatorenal syndrome in the United States: Nationwide inpatient sample

BACKGROUND

Hepatorenal syndrome (HRS) is a life-threatening condition among patients with advanced liver disease. Data trends specific to hospital mortality and hospital admission resource utilization for HRS remain limited.

AIM

To assess the temporal trend in mortality and identify the predictors for mortality among hospital admissions for HRS in the United States.

METHODS

We used the National Inpatient Sample database to identify an unweighted sample of 4938 hospital admissions for HRS from 2005 to 2014 (weighted sample of 23973 admissions). The primary outcomes were temporal trends in mortality as well as predictors for hospital mortality. We estimated odds ratios from multi-level mixed effect logistic regression to identify patient characteristics and treatments associated with hospital mortality.

RESULTS

Overall hospital mortality was 32%. Hospital mortality decreased from 44% in 2005 to 24% in 2014 (P < 0.001), while there was an increase in the rate of liver transplantation (P = 0.02), renal replacement therapy (P < 0.001), length of hospital stay (P < 0.001), and hospitalization cost (P < 0.001). On multivariable analysis, older age, alcohol use, coagulopathy, neurological disorder, and need for mechanical ventilation predicted higher hospital mortality, whereas liver transplantation, transjugular intrahepatic portosystemic shunt, and abdominal paracentesis were associated with lower hospital mortality.

CONCLUSION

Although there was an increase in resource utilizations, hospital mortality among patients admitted for HRS significantly improved. Several predictors for hospital mortality were identified.

The prognostic impact of different stages of acute kidney injury in patients with decompensated cirrhosis: a prospective cohort study

AIM

To assess the impact of the different stages of acute kidney injury (AKI) on the prognosis of patients hospitalized with decompensated cirrhosis.

METHODS

This was a prospective cohort study of consecutive patients admitted in two tertiary hospitals in southern Brazil. Participants were considered eligible if they were admitted for acute decompensation of cirrhosis. The main exposure factor was the onset of AKI. AKI stages were defined according the European recommendations. The outcomes evaluated were survival time and death rates at 28 and 90 days from hospital admission. A χ2 test was used to compare mortality between groups. Kaplan-Meier survival analyses were undertaken assessing time to event as days from AKI diagnosis to death or liver transplant.

RESULTS

Two hundred and five patients were included in the study, and 121 met the criteria for AKI. Patients with AKI 1b, AKI 2 and AKI 3 had higher 90-day mortality than patients without AKI (P = 0.008, P < 0.001 and P < 0.001, respectively). However, there was no difference in 90-day mortality when patients with AKI 1a were compared with those without AKI (P = 0.742). The mean survival of patients without AKI was higher than that of patients with AKI 1b (591.4 and 305.4 days, respectively, P = 0.015), while there was no significant difference between the mean survival of patients without AKI and that of patients with AKI 1a (591.4 and 373.6 days, respectively, P = 0.198).

CONCLUSION

Only AKI ≥1b seems to substantially impact mortality of patients hospitalized for acute decompensation of cirrhosis.

Plasma Cystatin C Level is a Prognostic Marker of Morbidity and Mortality in Hospitalized Decompensated Cirrhotic Patients

Introduction : Cystatin C (CysC) is biomarker for early detection of acute kidney injury (AKI). However, there is limited evidence in decompensated cirrhotic patients without AKI at admission. This study aimed to assess CysC as a predictor of 90-day mortality. Methods : Decompensated cirrhotic patients without AKI were prospectively enrolled. CysC and creatinine were measured within 24 hours of admission and compared between patients with in-hospital complications (AKI, hepatorenal syndrome (HRS), acute-on-chronic liver failure (ACLF)) vs. those without, and survivors vs. non-survivors. The AUROC and cut-off point of CysC in predicting 90-day mortality were determined. Results : Of 137 decompensated cirrhotic patients, 46 without AKI at admission were included (58.7% male, age 60.8 ± 11.2years, MELD 13.1 ± 5.1, ChildA / B / C 43.5% / 39.1% / 17.4%). The mean CysC level tended to be higher in patients with ACLF (1.52 ± 0.60 vs. 1.11 ± 0.28, p = 0.05), and significantly higher in non-survivors than survivors (1.61 ± 0.53 vs. 1.08 ± 0.28, p = 0.013). The 90-day mortality rate was 21.7%. After adjusting with age and bacterial infection on admission, CysC level  ≥ 1.25 mg / L was significantly associated with 90-day mortality. The CysC cut-off level  ≥ 1.25 mg / L provided 80% sensitivity and 75% specificity for predicting 90-day mortality. Conclusion : Plasma CysC within 24 hours could be used as a predictor for 90-day mortality and development of ACLF in decompensated cirrhotic patients. J. Med. Invest. 68 : 302-308, August, 2021.

Risk and protective factors of acute kidney injury in decompensated cirrhotic patients with ascites on tolvaptan

Background and Aim

Acute kidney injury (AKI) is a life‐threatening complication of liver cirrhosis. Here, we evaluated the risk factors and characteristics of AKI in cirrhosis.

Patients/Methods

This was a single‐center retrospective study. A total of 199 Japanese patients with decompensated liver cirrhosis (104 men, median age 61 years) were enrolled and received tolvaptan orally. Survival rates and new onset of AKI were monitored, and risk factors were evaluated.

Results

Forty‐six patients (23.1%) suffered an AKI complication and exhibited significantly poorer survival (P < 0.01). The rates of hepatic encephalopathy (P < 0.01) and chronic kidney disease (CKD; P = 0.02) were significantly increased in patients with AKI. The rate of proton pump inhibitor (PPI)/H2 blocker treatment (P = 0.04) was significantly lower, whereas that of ascites drainage was significantly higher in the AKI cases (P < 0.01). The AKI risk was significantly increased in patients with hepatic encephalopathy (HR 4.18, 95% CI 1.618–10.771). In contrast, the incidence of AKI was significantly lower in patients with a higher serum albumin level (HR 0.36, 95% CI 0.142–0.914, P = 0.03). Treatment with PPI/H2 blockers (HR 0.30, 95% CI 0.126–0.711, P < 0.01) or kanamycin/rifaximin (HR 0.26, 95% CI 0.075–0.929, P = 0.04) was significantly associated with a reduced risk of AKI development.

Conclusions

AKI incidence was increased in patients with decreased liver function and was associated with poor survival. PPI/H2 blocker or kanamycin/rifaximin treatment may reduce the risk of AKI.

Renal-function change after transjugular intra-hepatic portosystemic shunt placement and its relationship with survival: a single-center experience

Background

The effect of transjugular intra-hepatic portosystemic shunt (TIPS) placement on renal function and the correlation of post-TIPS Cr with mortality remain unclear. This study aimed to assess the effect of TIPS placement on renal function and to examine the relationship between post-TIPS Cr and mortality risk.

Methods

A total of 593 patients who underwent de novo TIPS placement between 2004 and 2017 at a single institution were included in the study. The pre-TIPS Cr level (T0; within 7 days before TIPS placement) and post-TIPS Cr levels, at 1–2 days (T1), 5–12 days (T2), and 15–40 days (T3), were collected. Predictors of Cr change after TIPS placement and the 1-year mortality rate were analysed using multivariable linear-regression and Cox proportional-hazards models, respectively.

Results

Overall, 21.4% of patients (n = 127) had elevated baseline Cr (≥1.5 mg/dL; mean, 2.51 ± 1.49 mg/dL) and 78.6% (n = 466) had normal baseline Cr (<1.5 mg/dL; mean, 0.92 ± 0.26 mg/dL). Patients with elevated pre-TIPS Cr demonstrated a decrease in post-TIPS Cr (difference, −0.60 mg/dL), whereas patients with normal baseline Cr exhibited no change (difference, <0.01 mg/dL). The 30-day, 90-day, and 1-year mortality rates were 13%, 20%, and 32%, respectively. Variceal bleeding as a TIPS-placement indication (hazard ratio = 1.731; P = 0.036), higher T0 Cr (hazard ratio = 1.834; P = 0.012), and higher T3 Cr (hazard ratio = 3.524; P < 0.001) were associated with higher 1-year mortality risk.

Conclusion

TIPS placement improved renal function in patients with baseline renal dysfunction and the post-TIPS Cr level was a strong predictor of 1-year mortality risk.

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.

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.

Impact of acute kidney injury on mortality in patients with acute variceal bleeding

Background

The effect of acute kidney injury (AKI) on patients with acute variceal bleeding (AVB) using the recently proposed International Club of Ascites (ICA) criteria is unclear. This study aimed to evaluate the incidence of AKI using the ICA criteria and factors associated with the outcomes in cirrhotic patients with AVB.

Methods

This retrospective cohort study included data of cirrhotic patients with AVB from two centers in Korea. The association of the ICA criteria for AKI with 6-week mortality was analyzed through univariate and multivariate analyses using the Cox proportional hazard model.

Results

In total, there were 546 episodes of AVB in 390 patients, of which 425 and 121 episodes were due to esophageal and gastric variceal bleeding, respectively. Moreover, 153 patients fulfilled the ICA criteria for AKI, and 64, 30, 39, and 20 patients were diagnosed with stages 1a, 1b, 2, and 3, respectively. Conversely, 97 patients developed AKI within 42 days as per the conventional criteria. The 6-week mortality rate was significantly higher in patients with ICA-AKI than in patients without ICA-AKI; the occurrence of ICA-AKI was an independent factor for predicting the 6-week mortality.

Conclusion

The ICA criteria could help diagnose renal dysfunction earlier, and presence of AKI is a predictor of mortality in patients with cirrhosis and AVB.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01862-x.

New clinical and pathophysiological perspectives defining the trajectory of cirrhosis

Traditionally, the complications of cirrhosis, namely variceal bleeding, ascites and hepatic encephalopathy, were thought to result predominantly from circulatory dysfunction and altered organ perfusion arising as a result of portal hypertension. Over the past 20 years, large, international prospective studies have indicated the importance of systemic inflammation and organ immunopathology as additional determinants of organ dysfunction in cirrhosis, which not only manifests in the liver, brain, circulation and the kidneys, but also the immune system, gut, muscles, adrenal glands, reproductive organs, heart and lungs. This review provides an overview of the traditional and emerging concepts around the initiation and maintenance of organ dysfunction in cirrhosis and proposes a new paradigm based upon a better understanding of acute decompensation of cirrhosis. The interaction between the traditional concepts and the emerging perspectives remains a matter of great interest and the basis for future research.

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.

Position paper on liver and kidney diseases from the Italian Association for the Study of Liver (AISF), in collaboration with the Italian Society of Nephrology (SIN)

Liver and kidney are strictly connected in a reciprocal manner, in both the physiological and pathological condition. The Italian Association for the Study of Liver, in collaboration with the Italian Society of Nephrology, with this position paper aims to provide an up-to-date overview on the principal relationships between these two important organs. A panel of well-recognized international expert hepatologists and nephrologists identified five relevant topics: 1) The diagnosis of kidney damage in patients with chronic liver disease; 2) Acute kidney injury in liver cirrhosis; 3) Association between chronic liver disease and chronic kidney disease; 4) Kidney damage according to different etiology of liver disease; 5) Polycystic kidney and liver disease. The discussion process started with a review of the literature relating to each of the five major topics and clinical questions and related statements were subsequently formulated. The quality of evidence and strength of recommendations were graded according to the GRADE system. The statements presented here highlight the importance of strong collaboration between hepatologists and nephrologists for the management of critically ill patients, such as those with combined liver and kidney impairment.