AKI persistence at 48 h predicts mortality in patients with acute on chronic liver failure

APASL clinical practice guidelines on the management of acute kidney injury in acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is a syndrome that is characterized by the rapid development of organ failures predisposing these patients to a high risk of short-term early death. The main causes of organ failure in these patients are bacterial infections and systemic inflammation, both of which can be severe. For the majority of these patients, a prompt liver transplant is still the only effective course of treatment. Kidneys are one of the most frequent extrahepatic organs that are affected in patients with ACLF, since acute kidney injury (AKI) is reported in 22.8-34% of patients with ACLF. Approach and management of kidney injury could improve overall outcomes in these patients. Importantly, patients with ACLF more frequently have stage 3 AKI with a low rate of response to the current treatment modalities. The objective of the present position paper is to critically review and analyze the published data on AKI in ACLF, evolve a consensus, and provide recommendations for early diagnosis, pathophysiology, prevention, and management of AKI in patients with ACLF. In the absence of direct evidence, we propose expert opinions for guidance in managing AKI in this very challenging group of patients and focus on areas of future research. This consensus will be of major importance to all hepatologists, liver transplant surgeons, and intensivists across the globe.

Novel prognostic biomarkers in decompensated cirrhosis: a systematic review and meta-analysis

BACKGROUND

Patients with decompensated cirrhosis experience high mortality rates. Current prognostic scores, including the model for end-stage liver disease (MELD), may underperform in settings other than in those they were initially developed. Novel biomarkers have been proposed to improve prognostication accuracy and even to predict development of complications.

METHODS

We performed a systematic review and meta-analysis on novel urine and blood biomarkers and their ability to predict 90-day mortality in patients with decompensated cirrhosis. Secondary outcomes included 28-day and 1-year mortality, and development of acute-on-chronic liver failure, acute kidney injury and other complications. To overcome differences in units, temporal changes in assays and reporting heterogeneity, we used the ratio of means (RoM) as measure of association for assessing strength in predicting outcomes. An RoM>1 implies that the mean biomarker level is higher in those that develop the outcome than in those that do not.

RESULTS

Of 6629 unique references, 103 were included, reporting on 29 different biomarkers, with a total of 31 362 biomarker patients. Most studies were prospective cohorts of hospitalised patients (median Child-Pugh-Turcotte score of 9 and MELD score of 18). The pooled 90-day mortality rate was 0.27 (95% CI 0.24 to 0.29). The RoM for predicting 90-day mortality was highest for interleukin 6 (IL-6) (2.56, 95% CI 2.39 to 2.74), followed by urinary neutrophil gelatinase-associated lipocalin (uNGAL) (2.42, 95% CI 2.20 to 2.66) and copeptin (2.33, 95% CI 2.17 to 2.50). These RoMs were all higher than for MELD (1.44, 95% CI 1.42 to 1.46).

CONCLUSION

Novel biomarkers, including IL-6, uNGAL and copeptin, can probably improve prognostication of patients with decompensated cirrhosis compared with MELD alone.

Determinants of Short-term Mortality in Liver Cirrhosis with Acute Kidney Injury: A Prospective Observational Study

Background: Acute kidney injury (AKI) occurs in 20-50% of patients with cirrhosis and is associated with a poor prognosis. The aim of the study is to identify the baseline factors affecting mortality in these patients at 30 and 90 days. Methods: We enrolled 117 patients with cirrhosis and AKI and followed them up prospectively. Results: Distribution of International club of ascites AKI stages was: 26 (22.03%) stage 1, 59 (50%) stage 2, and 33 (28%) stage 3. Mortalities at 30 and 90 days were 27 (22.8%) and 33 (27.9%) respectively. On multivariate analysis, variables affecting mortality at 30 days were serum creatinine level>2 mg% at 48 hours after AKI development (adjusted OR 7.93, P=0.02) and leukocytosis (total leucocyte count>11000/mm3 ) at admission (adjusted OR 6.54, P=0.002). Only leukocytosis at admission was a predictor of 90 days mortality (adjusted OR 4.76, P=0.01). Though not statistically significant, patients not responding to standard medical treatment had 3 times higher mortality at 30 days, while the maximum AKI stages (2 and 3) had eight times higher mortality at 90 days. Conclusion: In cirrhosis, AKI increases short-term mortality. High serum creatinine at 48 hours affects mortality at 30 days, while leukocytosis at baseline predicts mortality at 30 and 90 days. Progression to a higher AKI stage impacts prognosis.

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.

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

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

INASL-ISN Joint Position Statements on Management of Patients with Simultaneous Liver and Kidney Disease

Renal dysfunction is very common among patients with chronic liver disease, and concomitant liver disease can occur among patients with chronic kidney disease. The spectrum of clinical presentation and underlying etiology is wide when concomitant kidney and liver disease occur in the same patient. Management of these patients with dual onslaught is challenging and requires a team approach of hepatologists and nephrologists. No recent guidelines exist on algorithmic approach toward diagnosis and management of these challenging patients. The Indian National Association for Study of Liver (INASL) in association with Indian Society of Nephrology (ISN) endeavored to develop joint guidelines on diagnosis and management of patients who have simultaneous liver and kidney disease. For generating these guidelines, an INASL-ISN Taskforce was constituted, which had members from both the societies. The taskforce first identified contentious issues on various aspects of simultaneous liver and kidney diseases, which were allotted to individual members of the taskforce who reviewed them in detail. A round-table meeting of the Taskforce was held on 20-21 October 2018 at New Delhi to discuss, debate, and finalize the consensus statements. The evidence and recommendations in these guidelines have been graded according to the Grading of Recommendations Assessment Development and Evaluation (GRADE) system with minor modifications. The strength of recommendations (strong and weak) thus reflects the quality (grade) of underlying evidence (I, II, III). We present here the INASL-ISN Joint Position Statements on Management of Patients with Simultaneous Liver and Kidney Disease.

Prevalence and short-term outcome of acute kidney injury in patients with acute-on-chronic liver failure: A meta-analysis

Acute kidney injury (AKI) in patients with acute-on-chronic liver failure (ACLF) is a distinct syndrome to that in patients with cirrhosis, yet is less characterized. The aim of this meta-analysis was to investigate the impact of AKI on outcome of ACLF. We searched PubMed, Web of Science and Cochrane Library for original articles that evaluated the impact of AKI on outcome of ACLF from 2011 to 2019. Odds ratio (OR) with 95% confidence interval (CI) for 1-month and 3-month mortality was calculated. The response rate of vasoconstrictor for hepatorenal syndrome (HRS)-AKI was assessed. Eight relevant articles with 3610 patients were included. The prevalence of AKI in ACLF patients was 41% (95% CI 32%-50%). The presence of AKI was significantly associated with 1-month mortality of ACLF (OR 3.98, 95% CI 3.09-5.12; P < .001) and 3-month mortality (OR 4.98, 95% CI 3.59-6.92; P < .001). Additionally, patients with AKI stage ≥2 showed a higher 3-month mortality than stage 1 (OR 3.89, 95% CI 2.60-5.82; P < .001), and those of stage 3 had a higher mortality than stage ≤2 (OR 3.77, 95% CI 2.10-6.77; P < .001). The pooled response rate of vasoconstrictors was 32% (95% CI 26%-37%). This meta-analysis indicated that about 40% of ACLF patients complicated with AKI and the presence of AKI substantially increased the short-term mortality, together with a poor response rate of vasoconstrictors for HRS-AKI.

Development of a novel ssDNA aptamer targeting neutrophil gelatinase-associated lipocalin and its application in clinical trials

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a promising biomarker of early diagnosis and prediction for acute kidney injury (AKI). However, the current program for NGAL detection is not extensively applied in clinics due to the high expense of antibodies. Nucleic acid aptamers are single-strand DNAs or RNAs which could bind to targets with high specificity and affinity, and they have been widely used in the diagnosis and therapy for multiple diseases. It is valuable for us to develop a new method for NGAL detection using aptamers instead of antibodies to achieve increased efficiency and decreased cost.

METHODS

Nucleic acid aptamers against NGAL were obtained after SELEX process using magnetic beads, and an enzyme-linked aptamer analysis (ELAA), which can be widely used in clinical diagnosis at low cost, were successfully established. The feasibility of ELAA was further validated with urine samples harvested from 43 AKI patients and 30 healthy people.

RESULTS

Three candidate aptamers, including NA36, NA42 and NA53, were obtained after 8 rounds of SELEX process with magnetic beads and verified by quantitative polymerase chain reaction (qPCR), and the Kd value of each aptamer was 43.59, 66.55 and 32.52 nM, respectively. Moreover, the linear relationship was consistent at the range of 125-4000 ng/mL, and the detection limit of ELAA assay was 30.45 ng/mL. We also found that NGAL could be exclusively detected with NA53, and no cross-reaction between NA53 and human albumin or globulin occurred, the coefficient of variation (CV) between inner-plate and inter-plate was less than 15%, and the recovery rate was between 80 and 110%. Moreover, the sensitivity and specificity of ELAA assay in this study are 100% and 90%, respectively. Consistently, these results could also diagnose whether the occurrence of AKI in lots of patients, which has been demonstrated with the ELAA method we established after using NA53.

CONCLUSIONS

Taken together, NA53, the best candidate aptamer targeting NGAL protein, can be applied in clinical testing.

Acute Kidney Injury at Admission Is a Better Predictor of Mortality than Its Persistence at 48 h in Patients with Acute-on-chronic Liver Failure

Background and Aims: Acute kidney injury (AKI) occurs commonly in patients with acute-on-chronic liver failure (ACLF). However, there are scant data regarding the impact of AKI on survival in ACLF. We performed a prospective study to evaluate the impact of AKI on survival in ACLF.

Methods: This study was conducted in ACLF patients hospitalized in the Gastroenterology Department of Sriram Chandra Bhanja Medical College (India) between October 2016 and February 2018. Demographic, clinical and laboratory parameters were recorded, and outcomes were compared between patients with and without AKI and between patients with persistent AKI and AKI reversal at 48 h.

Results: We screened 439 chronic liver disease patients as per the Asian Pacific Association for the Study of the Liver criteria and found that 113 (25.7%) of them had ACLF and 78 (69%) of them had AKI as per the Acute Kidney Injury Network criteria. ACLF patients with AKI had reduced 28-day survival (44.9% vs. 74.3%; p = 0.004) and 90-day survival (25.6% vs. 51.4%; p = 0.007), in comparison to ACLF patients without AKI. However, when comparison was made between AKI reverters and AKI persisters at 48 h, survival was comparable for both at 28 days and 90 days. Further, about one-tenth of ACLF patients with AKI died within 48 h of hospitalization.

Conclusions: Over two-thirds of ACLF patients had AKI. Although ACLF itself is a predictor of reduced survival, a very small increase in serum creatinine further worsens survival. Importantly, AKI at admission is a better predictor of early mortality in ACLF patients since recovery from AKI at 48 h does not improve survival.

Predictive Value of Serum Creatinine, Blood Urea Nitrogen, Uric Acid, and β2-Microglobulin in the Evaluation of Acute Kidney Injury after Orthotopic Liver Transplantation

Background

As a major complication after orthotopic liver transplantation (OLT), the occurrence of acute kidney injury (AKI) is frequently defined by serum creatinine (Cr); however, the accuracy of commonly used blood urea nitrogen (BUN), uric acid (UA), and β₂-microglobulin (β₂-MG) remains to be explored. This retrospective study compared the accuracy of these parameters for post-OLT AKI evaluation.

Methods

Patients who underwent OLT in three centers between July 2003 and December 2013 were enrolled. The postoperative AKI group was diagnosed by the Kidney Disease Improving Global Outcomes (KDIGO) criteria and classified by stage. Measurement data were analyzed using the t-test or Wilcoxon rank-sum test; enumerated data were analyzed using the Chi-square test or Fisher's exact test. Diagnostic reliability and predictive accuracy were evaluated using receiver operating characteristic (ROC) curve analysis.

Results

This study excluded 976 cases and analyzed 697 patients (578 men and 119 women); the post-OLT AKI incidence was 0.409. Compared with the no-AKI group, the AKI group showed very significant differences in Model for End-stage Liver Disease score (14.74 ± 9.91 vs. 11.07 ± 9.54, Z = 5.404; P < 0.001), hepatic encephalopathy (45 [15.8%] vs. 30 [7.3%], χ² = 12.699; P < 0.001), hemofiltration (28 [9.8%] vs. 0 [0.0%], χ² = 42.171; P < 0.001), and 28-day mortality (23 [8.1%] vs. 9 [2.2%], χ² = 13.323; P <0.001). Moreover, mean values of Cr, BUN, UA, and β₂-MG in the AKI group differed significantly at postoperative days 1, 3, and 7 (all P < 0.001). ROC curve area was 0.847 of Cr for the detection of AKI Stage 1 (sensitivity 80.1%, specificity 75.7%, cutoff value 88.23 μmol/L), 0.916 for Stage 2 (sensitivity 87.6%, specificity 82.6%, cutoff value 99.9 μmol/L), and 0.972 for Stage 3 (sensitivity 94.1%, specificity 88.2%, cutoff value 122.90 μmol/L).

Conclusion

The sensitivity and specificity of serum Cr might be a high-value indicator for the diagnosis and grading of post-OLT AKI.