New ICA criteria for the diagnosis of acute kidney injury in cirrhotic patients: can we use an imputed value of serum creatinine?

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.

Hepatorenal Syndrome-Acute Kidney Injury in Liver Transplantation

Hepatorenal syndrome (HRS) is a serious complication of cirrhosis. HRS nomenclature has recently changed to HRS-AKI (acute kidney injury). HRS is a complex response to chronic vasodilatory changes brought about by portal hypertension and exacerbated by inflammatory responses that portends poor prognosis to patients with cirrhosis. This syndrome is commonly seen in the setting of infections, particularly spontaneous bacterial peritonitis. Because of the frequency of renal injury in the patient with cirrhosis, HRS-AKI has to be considered high in the differential diagnosis of AKI. Discontinuation of potential triggering agents and elimination of pre-renal AKI, intrinsic renal disease, and structural uropathy as causes of injury are imperative on presentation. Volume expansion with albumin and vasoconstrictive drugs to counteract the underlying splanchnic vasodilation constitutes the most effective medical modality to manage this process. Although the most effective therapy is generally considered to be liver transplantation (LT), the logistic barriers of offering this life-saving therapy on time to all needing it is a major limitation. Terlipressin has been shown to reverse HRS-AKI in a significant proportion of those treated and consequently can lead to increased LT patient survival and freedom from renal replacement therapy. We will review the impact of HRS on the management of patients awaiting LT, present strategies to prevent this significant complication, and discuss major implications of recent therapeutic advances in the setting of LT.

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.

Definition, diagnosis and epidemiology of acute-on-chronic liver failure

This narrative review addresses the definition of acute-on-chronic liver failure, a condition associated with high short-term mortality in patients with chronic liver disease and/or cirrhosis. We provide two major points of view: the East and the West perspective. Both definitions vary regarding the underlying patient population and organ failure(s) definition. Nevertheless, all the definitions have their clinical utility: from the core concept of having the "liver" as a conditio sine qua non, the syndrome cannot exist (Asian Pacific Association for the Study of the Liver); a data-driven, robust definition (European Association for the Study of the Liver); a bedside tool that can quickly identify patients at high risk of dying (North American Consortium for the Study of End-stage Liver Disease [NACSELD]). In each section, we provide the overall definitions, the criteria of organ failure(s), and some epidemiological data illustrating how these apply in each area of the world.

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.

Value of Acute Kidney Injury in Predicting Mortality in Vietnamese Patients with Decompensated Cirrhosis

Background: Acute kidney injury remains a common complication with a poor prognosis, and is a significant predictor of mortality in cirrhosis patients. We aimed to determine the percentage of acute kidney injury in decompensated cirrhosis patients and evaluate the treatment results of acute kidney injury as well as several factors related to the mortality of decompensated cirrhosis patients. Methods: A prospective study was conducted on decompensated cirrhosis patients in Can Tho City, Vietnam, from 2019 to 2020. Decompensated cirrhosis patients were found to have acute kidney injury on admission by a blood creatinine test. They were treated according to ICA 2015 standards, after which they were monitored and evaluated for treatment outcomes during hospitalization. Results: Of 250 decompensated cirrhosis patients, 64 (25.6%) had acute kidney injury and 37.5% died. Several factors were associated with mortality in decompensated cirrhosis patients, such as Child–Pugh C (p = 0.02; OR = 3, 95% CI 1.5–6.3), acute kidney injury (p < 0.0001; OR = 9.5, 95% CI 4.3–21.1), hyponatremia (p = 0.01; OR = 2.5, 95% CI 1.2–5.1), elevated total bilirubin > 51 µmol/L (p = 0.03; OR = 2.2, 95% CI 1.1–4.6), and prothrombin < 70% (p = 0.03; OR = 6.8, 95% CI 1–51.6). Hypoalbuminemia was unrelated to mortality in these patients (p = 0.8; OR = 1.2, 95% CI 0.5–2.7), but gastrointestinal bleeding significantly increased mortality in these patients up to 2.3 times (p = 0.03; OR = 2.3, 95% CI 1.1–4.9). Three independent factors regarding mortality in decompensated cirrhosis patients included acute kidney injury, hepatic encephalopathy, and gastrointestinal bleeding. The rate of acute kidney injury in patients with decompensated cirrhosis was 25.6%; the mortality rate was 37.5%. Conclusions: Acute kidney injury was a valuable predictor of mortality in Vietnamese patients with decompensated cirrhosis.

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.

Estimating Glomerular Filtration Rate in Cirrhosis Using Creatinine-Based and Cystatin C-Based Equations: Systematic Review and Meta-Analysis

Accurate estimation of kidney function in cirrhosis is crucial for prognosis and decisions regarding dual-organ transplantation. We performed a systematic review/meta-analysis to assess the performance of creatinine-based and cystatin C (CysC)-based eGFR equations compared with measured GFR (mGFR) in patients with cirrhosis. A total of 25 studies (n = 4565, 52.0 years, 37.0% women) comprising 18 equations met the inclusion criteria. In all GFR equations, the creatinine-based equations overestimated GFR (standardized mean difference, SMD, 0.51; 95% confidence interval [CI], 0.31-0.71) and CysC-based equations underestimated GFR (SMD, -0.3; 95% CI, -0.60 to -0.02). Equations based on both creatinine and CysC were the least biased (SMD, -0.14; 95% CI, -0.46 to 0.18). Chronic kidney disease-Epi-serum creatinine-CysC (CESC) was the least biased but had low precision and underestimated GFR by -3.6 mL/minute/1.73 m² (95% CI, -17.4 to 10.3). All equations significantly overestimated GFR (+21.7 mL/minute/1.73 m² ; 95% CI, 17.7-25.7) at GFR <60 mL/minute/1.73 m² ; of these, chronic kidney disease-Epi-CysC (10.3 mL/minute/1.73 m² ; 95% CI, 2.1-18.4) and GFR Assessment in Liver Disease (12.6 mL/minute/1.73 m² ; 95% CI, 7.2-18.0) were the least biased followed by Royal Free Hospital (15 mL/minute/1.73 m² ; 95% CI, 5.5-24.6) and Modification of Diet in Renal Disease 6 (15.7 mL/minute/1.73 m² ; 95% CI, 10.6-20.8); however, there was an overlap in the precision of estimates, and the studies were limited. In ascites, overestimation of GFR was common (+8.3 mL/minute/1.73 m² ; 95% CI, -3.1 to 19.7). However, overestimation of GFR by 10 to 20 mL/minute/1.73m² is common in patients with cirrhosis with most equations in ascites and/or kidney dysfunction. A tailored approach is required especially for decisions regarding dual-organ transplantation.

Portal Hypertension and Ascites: Patient-and Population-centered Clinical Practice Guidelines by the Italian Association for the Study of the Liver (AISF)

Portal hypertension and ascites are two crucial events in the natural history of liver cirrhosis, whose appearance marks a downward shift in the prognosis of the disease. Over the years, several international and national societies have issued clinical practice guidelines for the diagnosis and management of portal hypertension and ascites. The present document addresses the needs of an updated guidance on the clinical management of these conditions. Accordingly, the AISF Governing Board appointed a multi-disciplinary committee of experts for drafting an update of the most recent EASL Clinical Practice Guidelines. The aim of this work was to adapt the EASL recommendations to national regulations and resources, local circumstances and settings, infrastructure, and cost/benefit strategies to avoid duplication of efforts and optimize resource utilization. The committee defined the objectives, the key issues and retrieved the relevant evidence by performing a systematic review of the literature. Finally, the committee members (chosen on the basis of their specific expertise) identified the guidelines' key questions and developed them following the PICO format (Population, Intervention, Comparison, Outcomes). For each of the PICO questions, the systematic review of the literature was made on the most important scientific databases (Pubmed, Scopus, Embase).

Natural history of acute kidney disease in patients with cirrhosis

BACKGROUND & AIMS

In 2012, the KDIGO group proposed new definitions for acute kidney injury (AKI), acute kidney disease (AKD) and chronic kidney disease (CKD). According to the definition adapted by the International Club of Ascites, AKI has been extensively investigated in patients with cirrhosis. On the contrary, there are currently no data on the epidemiology and clinical outcomes associated with AKD. The aim of the study was to assess the prevalence and the impact of AKD on the clinical course and survival of patients with cirrhosis.

METHODS

A total of 272 consecutive patients with cirrhosis attending our outpatient clinic were included in the study. Clinical and laboratory data were collected at inclusion. Patients were followed-up until death, liver transplant or the end of follow-up.

RESULTS

During follow-up, 80 patients developed AKD (29.4%). Forty-two (52.5%) recovered from the first episode of AKD and 26 maintained a normal renal function up to the end of follow-up. Sixteen patients developed a second episode of AKD. Globally, 36 patients (45.0%) died with AKD. Finally, AKD progressed to CKD in 11 patients (13.8%). The 5-year survival rate was significantly lower in patients who developed AKD than in those who did not (34.8% vs. 88.8%, p <0.001). The 5-year rates of complications of cirrhosis and of hospitalizations were also higher in patients with AKD than in those without AKD.

CONCLUSIONS

AKD is frequent in patients with cirrhosis. It can be reversible, but it may recur and progress to CKD. AKD has a very negative impact on morbidity and mortality in patients with cirrhosis.

LAY SUMMARY

Renal impairment has a very negative impact on patients with cirrhosis. Renal impairment seems to be characterized by a very dynamic course, which is defined according to renal function and length of the impairment as acute kidney injury, acute kidney disease and chronic kidney disease. The role of acute kidney disease is currently unknown. Our study shows for the first time that acute kidney disease is frequent in patients with cirrhosis and has a very negative impact on survival.

Chinese guidelines on the management of liver cirrhosis (abbreviated version)

Based on reviews of the literature and experts' consensus, the Chinese Society of Hepatology developed guidelines for the diagnosis and treatment of liver cirrhosis, in order to improve clinical practice. In addition to what has been covered in previously published guidelines on the management of cirrhosis complications, these guidelines add new sections and provide updates. The guidelines emphasize the early diagnosis of the cause and assessment of complications. Comprehensive treatments including etiological treatment and complication management should be initiated immediately. In addition, regular monitoring, especially surveillance of hepatocellular carcinoma, is crucial for managing patients.

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

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

Metabolic Acidosis in Critically Ill Cirrhotic Patients with Acute Kidney Injury

Background and Aims: The metabolic acid-base disorders have a high incidence of acute kidney injury (AKI) in critically ill cirrhotic patients (CICPs). The aims of our study were to ascertain the composition of metabolic acidosis of CICPs with AKI and explore its relationship with hospital mortality. Methods: Three-hundred and eighty consecutive CICPs with AKI were eligible for the cohort study. Demographic, clinical and laboratory parameters were recorded and arterial acid-base state was analyzed by the Stewart and Gilfix methodology. Results: Net metabolic acidosis, lactic acidosis, acidosis owing to unmeasured anions, acidemia, and dilutional acidosis were less frequent in the non-survival group compared to the survival group of CICPs. The presence of acidemia, acidosis owing to unmeasured anions, and lactic acidosis were independently associated with increased risk of intensive care unit 30-day mortality, with hazard ratios of 2.11 (95% confidence interval (CI): 1.43-3.12), 3.38 (95% CI: 2.36-4.84), and 2.16 (95% CI: 1.47-3.35), respectively. After full adjustment for confounders, the relationship between acidosis owing to unmeasured anions with hospital mortality was still significant, with hazard ratio of 2.29 (95% CI: 1.22-4.30). Furthermore, arterial lactate concentration in combination with chronic liver failure-sequential organ failure assessment and BE_UMA had the strongest ability to differentiate 30-day mortality (area under the receiver operating characteristic curve: 0.79, 95% CI: 0.74-0.83). Conclusions: CICPs with AKI exhibit a complex metabolic acidosis during intensive care unit admission. Lactic acidosis and BE_UMA, novel markers of acid-base disorders, show promise in predicting mortality rate of CICPs with AKI.

Estimation of renal function in patients with liver cirrhosis: Impact of muscle mass and sex

BACKGROUND & AIMS

Accurate evaluation of renal function in patients with liver cirrhosis is critical for clinical management. However, there are still discrepancies between the measured glomerular filtration rate (mGFR) and creatinine-based estimated GFR (eGFR). In this study, we compared the performance of 2 common eGFR measurements with mGFR and evaluated the impact of low muscle mass on overestimation of renal function in patients with cirrhosis.

METHODS

This study included 779 consecutive cirrhotic patients who underwent ⁵¹Cr-ethylenediamine tetra acetic acid (EDTA) (as a mGFR) and abdominal computed tomography (CT). The eGFR was calculated using creatinine or cystatin C. Muscle mass was assessed in terms of the total skeletal muscle at L3 level using CT.

RESULTS

Modification of diet in renal disease (MDRD)-eGFR was overestimated in 47% of patients. A multivariate analysis showed that female sex (adjusted odds ratio [aOR] 4.91), Child B and C vs. A (aOR 1.69 and 1.84) and skeletal muscle mass (aOR 0.89) were independent risk factors associated with overestimation. Interestingly, the effect of skeletal muscle mass on overestimation varied based on sex. Decreased muscle mass significantly enhanced the risk of overestimation of MDRD-eGFR in male patients, but not in female patients. Cystatin C-based eGFR showed a better correlation with mGFR than MDRD-eGFR; it was also better at predicting overall survival and the incidence of acute kidney injury than MDRD-eGFR.

CONCLUSIONS

The risk factors associated with overestimation included female sex, impaired liver function, and decreased muscle mass in males. In particular, eGFR in male patients with sarcopenia should be carefully interpreted. Creatinine-based eGFR was overestimated more often than cystatin C-based eGFR, with overestimation of eGFR closely related to poor prognostic performance.

LAY SUMMARY

Overestimation of renal function frequently occurs in patients with liver cirrhosis when using serum creatinine. Decreased muscle mass has a great impact on overestimation of kidney function especially in male patients with cirrhosis. Compared with creatinine, cystatin C was more closely correlated with measured glomerular filtration rate and had a higher predictive ability for renal complications and survival than creatinine.

The Japanese clinical practice guideline for acute kidney injury 2016

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

Hepatorenal syndrome in the era of acute kidney injury

Acute kidney injury (AKI) is a frequent complication of patients with advanced cirrhosis that it is associated with increased hospital admissions and decreased survival. The definition of AKI in cirrhosis has been recently modified and the new diagnostic criteria are based on small changes in serum creatinine with respect to previous values, occurring within a short period of time. The use of this new definition may lead to an earlier identification of renal impairment and better prognostic stratification. Hepatorenal syndrome (HRS) is a unique form of AKI developing in patients with end-stage liver disease. Systemic circulatory dysfunction and marked kidney vasoconstriction play a key role in the development of HRS. The modification of the definition of AKI has also led to a change in the diagnostic criteria of HRS. The new diagnostic criteria are based on AKI stages and there is no need to reach a specific serum creatinine threshold. According to these new criteria, treatment with vasoconstrictors and albumin for the management of HRS will be started at lower serum creatinine values, with expected higher response rates. Finally, there are consistent data showing that some urine biomarkers, particularly NGAL (neutrophil gelatinase-associated lipocalin), may be useful in daily clinical practice for the differential diagnosis of the cause of AKI in cirrhosis.

Beyond serum creatinine: which tools to evaluate renal function in cirrhotic patients?

In cirrhotic patients, a high serum creatinine value is an independent mortality factor. Similarly, it is predictive of renal insufficiency after liver transplantation. In these cases, chronic kidney disease is also an independent mortality factor. A relevant evaluation of glomerular filtration rate is crucial, particularly in cases of end-stage liver disease or liver transplantation, and is key for the decision to undertake dual liver-kidney transplantation. Serum creatinine or creatinine-based equations are the most used tools in clinical practice but they significantly overestimate renal function. Equilibrium inulin renal clearance remains the gold standard but is time consuming and expensive. Cystatin C and cystatin C-based equations are less influenced by muscle mass or bilirubin value, but their dosage is not standardized and they are expensive. Pharmacological models using exogenous markers, new kidney biomarkers, Doppler coupled with ultrasounds, and kidney histology could be interesting tools but their indications need to be specified.

The Japanese Clinical Practice Guideline for acute kidney injury 2016

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

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

BACKGROUND/AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Why and how to measure renal function in patients with liver disease

Patients with advanced liver disease frequently have impaired renal function. Both acute kidney injury (AKI) and chronic kidney disease (CKD) are quite common in patients with cirrhosis and both are associated with a worse prognosis in these patients. A careful assessment of renal function is highly important in these patients to help physicians determine their diagnosis, prognosis and therapeutic management and to define transplantation strategies (liver transplantation alone vs simultaneous liver and kidney transplantation). Although they are still widely used in clinical practice, conventional biomarkers of renal function such as serum creatinine have several limitations in these patients. Recent progress has been made in the evaluation of renal function and new diagnostic criteria for AKI have been proposed. However, certain issues such as the noninvasive assessment of the glomerular filtration rate and/or improvement in the differential diagnosis between hepatorenal syndrome and acute tubular necrosis must still be addressed. The purposes of this paper are: (i) to highlight the importance of the evaluation of renal function in patients with cirrhosis; (ii) to review the state of the art in the assessment of renal function in these patients as well as advances that we expect will be made to improve the accuracy of available tools.

The evolving concept of acute kidney injury in patients with cirrhosis

Renal dysfunction is prevalent in patients with advanced cirrhosis and decompensation. The presence of type 1 hepatorenal syndrome (HRS) has traditionally been defined by a set of stringent criteria based on serum creatinine levels. These diagnostic criteria have been found to be too stringent to be widely applicable to patients with cirrhosis, leading to underdiagnosis of renal failure in this population. Acute kidney injury (AKI) has now been proposed to characterize renal dysfunction in patients with cirrhosis and is defined as an increase in serum creatinine by 0.3 mg/dl in <48 h or an increase in serum creatinine by 50% from a stable baseline reading within 3 months. Type 1 HRS is renamed HRS-AKI. Stage 1 AKI is defined by 0.3 mg/dl serum creatinine or a 50% increase, stages 2 and 3 AKI are defined by a two-fold and three-fold increase in serum creatinine levels, respectively. Data collected so far suggests that even stage 1 AKI is associated with worse prognosis in patients with cirrhosis. The progression of AKI usually indicates substantially worse outcomes. A panel of biomarkers, including inflammatory markers, are envisaged to complement and enhance our current diagnostic criteria in the future and provide aetiology of the AKI.