Un-precipitated acute kidney injury is uncommon among stable patients with cirrhosis and ascites

Incidence and risk factors of acute kidney injury in cirrhosis: a systematic review and meta-analysis of 5,202,232 outpatients, inpatients, and ICU-admitted patients

INTRODUCTION

Acute kidney injury (AKI) is a commonly seen condition in the natural course of cirrhosis. The aim of this study was to evaluate the pooled incidence and risk factors of AKI in different clinical stages and situations in patients with cirrhosis.

METHODS

Search was conducted on 13 December 2023 across MEDLINE (PubMed), Embase, and Cochrane databases. Meta-analysis was performed using a generalized linear mixed model.

RESULTS

In total, 73 studies with 5,202,232 patients were finally enrolled in the meta-analysis. AKI commonly occurs among hospitalized cirrhotics experiencing any decompensation event (29%) as well as among stable outpatients (28%) throughout a 1-year follow-up period. On admission, patients with infection or sepsis/septic shock had the highest AKI rate (47%), followed by those with hepatic encephalopathy (41%). Furthermore, the severity of liver disease proved to be a substantial driver for AKI development, while patients at intensive care unit had the greatest AKI incidence (61%).

CONCLUSIONS

Both hospitalized patients and stable outpatients with cirrhosis exhibited an elevated susceptibility to AKI. Patients at intensive care unit and those with severe liver disease, infection, sepsis/septic shock, hepatic encephalopathy, or acute on chronic liver failure upon admission are at higher risk for AKI.

TRIAL REGISTRATION

PROSPERO, registered 09/12/23, CRD42023487736.

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.

[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.

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.

Race Adjustment in eGFR Equations Does Not Improve Estimation of Acute Kidney Injury Events in Patients with Cirrhosis

BACKGROUND

Accuracy of glomerular filtration rate estimating (eGFR) equations has significant implications in cirrhosis, potentially guiding simultaneous liver kidney allocation and drug dosing. Most equations adjust for Black race, partially accounted for by reported differences in muscle mass by race. Patients with cirrhosis, however, are prone to sarcopenia which may mitigate such differences. We evaluated the association between baseline eGFR and incident acute kidney injury (AKI) in patients with cirrhosis with and without race adjustment.

METHODS

We conducted a retrospective national cohort study of veterans with cirrhosis. Baseline eGFR was calculated using multiple eGFR equations including Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), both with and without race adjustment. Poisson regression was used to investigate the association between baseline eGFR and incident AKI events per International Club of Ascites criteria.

RESULTS

We identified 72,267 patients with cirrhosis, who were 97.3% male, 57.8% white, and 19.7% Black. Over median follow-up 2.78 years (interquartile range 1.22-5.16), lower baseline eGFR by CKD-EPI was significantly associated with higher rates of AKI in adjusted models. For all equations this association was minimally impacted when race adjustment was removed. For example, removal of race adjustment from CKD-EPI resulted in a 0.1% increase in the association between lower eGFR and higher rate of AKI events per 15 mL/min/1.73 m² change (p < 0.001).

CONCLUSIONS

Race adjustment in eGFR equations did not enhance AKI risk estimation in patients with cirrhosis. Further study is warranted to assess the impacts of removing race from eGFR equations on clinical outcomes and policy.

A Review of Hepatorenal Syndrome

The development of acute kidney injury (AKI) is one of the most frequent complications in patients with cirrhosis. AKI due to volume depletion is the most common etiology and hepatorenal syndrome (HRS) is the second most common cause of AKI in these patients. HRS is the extreme form of kidney injury in patients with cirrhosis, which is caused due to a reduction in renal blood flow unresponsive to volume expansion. The literature involving HRS is rapidly evolving and newer tests and updated definitions have been proposed which allows timely identification and treatment. Here, we will discuss the definition, pathophysiology, prevention, diagnosis, and treatment of HRS.

End-stage liver disease: Management of hepatorenal syndrome

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

Kidney Function After Liver Transplantation in a Single Center

Background

Renal dysfunction in the peri-transplant period appears to complicate both short- and long-term outcome of liver transplantation (LT). The aim of this study was to analyze the impact of selected clinical features in the peri-liver transplant period, as well calcineurin inhibitor, particularly tacrolimus given after LT, on kidney function in a single liver transplant center’s experience.

Material/Methods

A total 125 consecutive liver-grafted individuals (82 M, 43 F), mean age 50±13 y (with alcohol-related liver disease in 48 (38%) patients) were included into the study. Their clinical data were collected in the database until 46 months of follow-up, and the Python packages Pandas (version 0.22.0) and scikit-learn (version 0.21.3) were used for data analysis.

Results

More advanced liver disease as judged by Child-Pugh class and MELD score differed significantly patients with preserved (serum creatinine SCr <1.5 mg/dL) and impaired (SCr ≥1.5 mg/dL) kidney function before LT. Older age and higher SCr pre-LT were associated with higher levels of SCr after LT in 2 time-points. SCr before LT was correlated with delta SCr for the highest and last recorded value (P<0.0001). Higher amounts of transfused colloids during surgery were associated with increased delta SCr for the highest value (P=0.019) after grafting in logistic regression analysis. There were no associations between SCr after LT and duration of anhepatic phase, urine output ≤100 mL/h, or post-reperfusion syndrome during transplantation (all P>0.05). There were no associations between SCr after LT and tacrolimus trough levels in analyses of correlations and linear regression analyses (all P>0.05).

Conclusions

We found that pretransplant serum creatinine was the only factor affecting kidney function after LT in our liver transplant center. The restricted fluid policy was safe and effective in terms of long-term renal function. The role of kidney-saving immunosuppressive protocols in preserving renal function long-term after LT was also confirmed.

Early echocardiographic signs of diastolic dysfunction predict acute kidney injury in cirrhotic patients

BACKGROUND

Cardiovascular dysfunction in cirrhotic patients affects survival and the development of cirrhotic complications. We aimed to evaluate potential echocardiographic parameters to predict mortality and acute kidney injury (AKI) in cirrhotic patients.

METHODS

A total of 103 cirrhotic patients who underwent echocardiography between February 2009 and August 2016 in Taipei Veterans General Hospital were retrospectively enrolled. Cardiac function was evaluated using transthoracic two-dimensional echocardiography with tissue Doppler imaging. Cox hazard regression analysis was used for assessing predictors for 1-year mortality and AKI within 1 year.

RESULTS

Baseline echocardiographic parameters were similar between survivors (n = 92) and nonsurvivors (n = 11). Lower serum levels of albumin, as well as higher albumin-bilirubin (ALBI) scores, Child-Pugh scores, and model for end-stage liver disease scores were observed in nonsurvivors. Cox proportional hazard regression analysis revealed Child-Pugh score as the only predictor of 1-year mortality. Baseline serum creatinine (Cr) > 1.5 mg/dL, total bilirubin > 2 mg/dL, and a higher E/e' ratio predict occurrence of AKI within 1 year. Among patients with serum Cr < 1.5 mg/dL, an increased atrial filling velocity and higher ALBI scores predict AKI occurrence within 1 year.

CONCLUSION

Severity of underlying liver disease but not echocardiographic parameters predicts 1-year mortality in cirrhosis. Early echocardiographic signs of diastolic dysfunction and higher ALBI scores may predict development of AKI in cirrhotic patients with serum Cr < 1.5 mg/dL.

Hepatorenal syndrome: pathophysiology, diagnosis, and management

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