Psychometric methods for diagnosing and monitoring minimal hepatic encephalopathy -current validation level and practical use

Working Memory in Patients with Varying Degree of Hepatic Encephalopathy (HE): A Pilot EEG-fNIRS Study

It is known that patients with covert hepatic encephalopathy (CHE) exhibit working memory abnormalities, but to date there is no study comparing patients with cirrhosis with/without CHE and controls with both electrophysiological and hemodynamic data collected at the same time.Here we collected behavioral [accuracy and reaction times (RTs), electrophysiological (evoked potentials) and hemodynamic (oxygenated and deoxygenated haemoglobin) correlates of an n-back task [formed by a control (0-back) condition, a low (1-back) and a high (2-back) working memory load conditions] in patients with cirrhosis with/without CHE: (1) at baseline (n = 21, males = 15, 58±8 yrs), and by comparison with controls (n = 21, males = 15, 57±11 yrs) and (2) after a 3-month course of rifaximin (n = 18, males = 12, 61±11 yrs), and by comparison to baseline.All patients showed slower RTs (p < 0.0001) and lower P2 amplitude compared with controls (p = 0.018); moreover, patients with CHE showed reduced accuracy (p < 0.0001) compared with controls, and patients without CHE showed higher oxygenated haemoglobin in the central dorsolateral prefrontal cortex in the 2-back compared with patients with CHE. Post-rifaximin, oxygenated haemoglobin increased in the central frontopolar cortex. In addition, in patients without CHE the RTs of the 2-back became comparable to those of the 0-back and P3 showed higher amplitude.In conclusion, the presence of cirrhosis seemed to have more effects than CHE on working memory at baseline. A course of treatment with rifaximin was more beneficial to patients without CHE, who probably had more room for improvement in this complex task.

Prevalence and Characteristics of Covert/Minimal Hepatic Encephalopathy in Patients With Liver Cirrhosis: A Systematic Review and Meta-Analysis

INTRODUCTION

Covert/minimal hepatic encephalopathy (C/MHE) is the mildest form of hepatic encephalopathy (HE), but it is closely related to the quality of life and prognosis of patients with cirrhosis. Currently, the epidemiological data of C/MHE have not been well described.

METHODS

We searched the PubMed, Embase, and Cochrane Library databases for relevant articles. We performed a random-effects meta-analysis of proportions to estimate the pooled prevalence of C/MHE in patients with cirrhosis. We also examined potential risk factors for C/MHE by comparing characteristics of patients with and without C/MHE.

RESULTS

Finally, a total of 101 studies were included. The prevalence of C/MHE was 40.9% (95% confidence interval, 38.3%-43.5%) among patients with cirrhosis worldwide. The pooled C/MHE prevalence was 39.9% (95% confidence interval 36.7%-43.1%) based on studies using the psychometric HE score as a diagnostic tool. Meta-regression models showed that geographic region, sample size, mean age, sex ratio, and Child-Pugh classification were influencing factors for the heterogeneity of C/MHE prevalence. The presence of C/MHE was found to be associated with various factors including age, level of education, alcoholic etiology, Child-Pugh classification, MELD score, history of overt HE, presence of other complications, and laboratory tests related to impaired liver function.

DISCUSSION

This study reports detailed data on the prevalence of C/MHE as well as clinical features associated with C/MHE, suggesting that C/MHE is one of the most common complications of liver cirrhosis.

Comparison of 6 tests for diagnosing minimal hepatic encephalopathy and predicting clinical outcome: A prospective, observational study

BACKGROUND AND AIMS

Current guidelines recommend the assessment for minimal HE in patients with liver cirrhosis. Various efforts were made to find tools that simplify the diagnosis. Here, we compare the 6 most frequently used tests for their validity and their predictive value for overt hepatic encephalopathy (oHE), rehospitalization, and death.

APPROACH AND RESULTS

One hundred thirty-two patients with cirrhosis underwent the Portosystemic Encephalopathy-Syndrome-Test yielding the psychometric hepatic encephalopathy score (PHES), Animal Naming Test (ANT), Critical Flicker Frequency (CFF), Inhibitory Control Test (ICT), EncephalApp (Stroop), and Continuous Reaction Time Test (CRT). Patients were monitored for 365 days regarding oHE development, rehospitalization, and death. Twenty-three patients showed clinical signs of HE grade 1-2 at baseline. Of the remaining 109 neurologically unimpaired patients, 35.8% had abnormal PHES and 44% abnormal CRT. Percentage of abnormal Stroop (79.8% vs. 52.3%), ANT (19.3% vs. 51.4%), ICT (28.4% vs. 36.7%), and CFF results (18.3% vs. 25.7%) changed significantly when adjusted norms were used for evaluation instead of fixed cutoffs. All test results correlated significantly with each other ( p <0.05), except for CFF. During follow-up, 24 patients developed oHE, 58 were readmitted to the hospital, and 20 died. Abnormal PHES results were linked to oHE development in the multivariable model. No other adjusted test demonstrated predictive value for any of the investigated endpoints.

CONCLUSIONS

Where applicable, the diagnosis of minimal HE should be made based on adjusted norm values for the tests, exclusively. The minimal HE tests cannot be equated with one another and have an overall limited value in predicting clinical outcomes.

Quantitative susceptibility mapping in rats with minimal hepatic encephalopathy: Does iron overload aggravate cognitive impairment by promoting neuroinflammation?

BACKGROUND AND AIMS

Minimal hepatic encephalopathy (MHE) is a mild form of hepatic encephalopathy that lacks observable signs and symptoms. Nevertheless, MHE can cause neurocognitive dysfunction, although the neurobiological mechanisms are not fully understood. Here, the effects of hippocampal iron deposition on cognitive function and its role in MHE were investigated.

MATERIALS AND METHODS

Eighteen rats were assigned to experimental and control groups. MHE was induced by thioacetamide. Spatial memory and exploratory behavior were assessed by the Morris water and elevated plus mazes. Hippocampal susceptibility was measured by quantitative susceptibility mapping, iron deposition in the hippocampus and liver by Prussian blue staining, and inflammatory cytokine and ferritin levels in the hippocampus were measured by ELISA.

RESULTS

MHE rats showed impaired spatial memory and exploratory behavior (P < 0.05 for all parameters). The bilateral hippocampal susceptibility values were significantly raised in MHE rats, together with evidence of neuroinflammation (increased pro-inflammatory and reduced anti-inflammatory cytokine levels (all P < 0.05). Further analysis indicated good correlations between hippocampal susceptibility values with latency time and inflammatory cytokine levels in MHE but not in control rats.

CONCLUSION

MHE induced by thioacetamide was associated with hippocampal iron deposition and inflammation, suggesting that iron overload may be an important driver of neuroinflammatory responses.

Development and validation of the AMMON-OHE model to predict risk of overt hepatic encephalopathy occurrence in outpatients with cirrhosis

BACKGROUND & AIMS

Neuropsychological and psychophysical tests are recommended to assess the risk of overt hepatic encephalopathy (OHE), but their accuracy is limited. Hyperammonaemia is central in the pathogenesis of OHE, but its predictive utility is unknown. In this study, we aimed to determine the role of neuropsychological or psychophysical tests and ammonia, and to develop a model (AMMON-OHE) to stratify the risk of subsequent OHE development in outpatients with cirrhosis.

METHODS

This observational, prospective study included 426 outpatients without previous OHE from three liver units followed for a median of 2.5 years. Psychometric hepatic encephalopathy score (PHES) <-4 or critical flicker frequency (CFF) <39 was considered abnormal. Ammonia was normalized to upper limit of normal (AMM-ULN) at the respective reference laboratory. Multivariable frailty competing risk and random survival forest analyses were performed to predict future OHE and to develop the AMMON-OHE model. External validation was carried out using 267 and 381 patients from two independent units.

RESULTS

Significant differences were found in time-to-OHE (log-rank p <0.001) according to PHES or CFF and ammonia, with the highest risk in patients with abnormal PHES plus high AMM-ULN (hazard ratio 4.4; 95% CI 2.4-8.1; p <0.001 compared with normal PHES and AMM-ULN). On multivariable analysis, AMM-ULN but not PHES or CFF was an independent predictor of the development of OHE (hazard ratio 1.4; 95% CI 1.1-1.9; p = 0.015). The AMMON-OHE model (sex, diabetes, albumin, creatinine and AMM-ULN) showed a C-index of 0.844 and 0.728 for the prediction of a first episode of OHE in two external validation cohorts.

CONCLUSIONS

In this study, we developed and validated the AMMON-OHE model, comprising readily available clinical and biochemical variables that can be used to identify outpatients at the highest risk of developing a first episode of OHE.

IMPACT AND IMPLICATIONS

In this study, we aimed to develop a model to predict which patients with cirrhosis are at risk of developing overt hepatic encephalopathy (OHE). Using data from three units and including 426 outpatients with cirrhosis, we developed the AMMON-OHE model - comprising sex, diabetes, albumin, creatinine and ammonia levels - which demonstrated good predictive ability. The AMMON-OHE model performs better than PHES and CFF to predict the first episode of OHE in outpatients with cirrhosis. This model was validated in 267 and 381 patients from two independent liver units. The AMMON-OHE model is available online for clinical use.

Predicting overt hepatic encephalopathy after TIPS: Value of three minimal hepatic encephalopathy tests

Background & Aims

Hepatic encephalopathy (HE) is a frequent and severe complication in patients after transjugular intrahepatic portosystemic shunt (TIPS) insertion. However, risk factors for post-TIPS HE remain poorly defined. Minimal HE (mHE) is a well-known risk factor for overt HE in patients with cirrhosis without TIPS. We aimed to evaluate three tools frequently used for diagnosing mHE for their dynamic changes and their predictive value for overt HE after TIPS.

Methods

We prospectively recruited 84 consecutive patients before TIPS insertion and monitored them for 180 days for post-TIPS HE. Before TIPS insertion, the patients underwent the portosystemic encephalopathy (PSE) syndrome test, the animal naming test (ANT), and the critical flicker frequency (CFF). Patients were retested after TIPS insertion.

Results

The majority of patients were male (67.9%), and the predominant indication for TIPS was refractory ascites (75%). Median age was 59 years, model for end-stage liver disease score was 12, and 66.3%, 64.6%, and 28.4% patients had evidence for mHE according to the PSE syndrome test, ANT, and CFF, respectively. Overall, 25 patients developed post-TIPS HE within 180 days after TIPS insertion. Post-TIPS incidence of overt HE was 22.2, 28.6, 45.5, and 55.6% in those with no, one, two, and three pathological tests at baseline, respectively. However, none of the three tests was significantly associated with post-TIPS HE. Of note, mean performance in all tests remained stable over time after TIPS insertion.

Conclusions

PSE syndrome test, ANT and CFF, which are frequently used for diagnosing mHE have limited value for predicting HE after TIPS insertion. We could not find evidence that TIPS insertion leads to a psychometric decline in the long term.

Impact and implications

This prospective observational study compared three diagnostic tests for mHE and showed the limited value of these tests for predicting overt HE in patients with cirrhosis undergoing TIPS insertion. In addition, the results suggest that cognitive performance generally remains stable after TIPS insertion. These results are important for physicians and researchers involved in the management of patients with cirrhosis undergoing TIPS procedures. The study's findings serve as a starting point for further investigations on the development of more effective strategies for predicting and managing post-TIPS HE.

Clinical trial number

ClinicalTrials.gov NCT04801290.

Clinical study of probiotics combined with lactulose for minimal hepatic encephalopathy treatment

OBJECTIVE

This study aimed to investigate the clinical effect of probiotics combined with lactulose for minimal hepatic encephalopathy (MHE) treatment.

METHODS

A total of 88 patients with MHE were randomly divided into the control ( n  = 44) and combined groups ( n  = 44). The control group was treated with lactulose, while the combined group was treated with probiotics and lactulose. Serum ammonia, liver function [alanine aminotransferase (ALT) and aspartate transaminase (AST)], intestinal mucosal barrier markers [fatty acid-binding protein 2 (FABP2) and advanced glycation end-products (AGEs)] and number connection test A (NCT-A) and digit symbol test (DST) scores were tested and compared between the two groups.

RESULTS

The post-treatment in the control and combined groups shows decreased serum ammonia levels, ALT and AST levels, FABP2 and AGEs levels and NCT-A score and increased DST score compared with pre-treatment, with a significant difference ( P  < 0.05). Post-treatment, the serum ammonia level, ALT and AST levels, FABP2 and AGEs levels, NCT-A score decreased and DST score increased in the combined group compared with the control group, with a significant difference ( P  < 0.05).

CONCLUSION

Probiotics can promote lactulose in MHE treatment.

Prediction and prevention of the first episode of overt hepatic encephalopathy in patients with cirrhosis

Hepatic encephalopathy (HE) is one of the most important complications of patients with liver cirrhosis. In addition, HE is associated with a dismal prognosis and has detrimental effects on patients' quality of life. Thus, it is of pivotal importance to identify patients at high risk for overt HE (OHE) in whom primary prophylaxis may be justified. In this narrative review, we aim to provide insight into predictors and prediction tools for a first-time episode of OHE and to scrutinize the current level of evidence of primary prophylaxis. In recent decades, several cognitive tests, composite scores, and blood-based biomarkers have been demonstrated to be predictive of a first-time episode of OHE. Among the best validated are the established tests for minimal HE, such as the Psychometric Hepatic Encephalopathy Score, determination of the critical flicker frequency, Stroop EncephalApp, or the Animal Naming Test. Individualized risk stratification using blood-based biomarkers and cross-sectional imaging (sarcopenia and spontaneous portosystemic shunts) is coming to the fore, but validation in larger multicenter cohorts is often lacking. On the basis of current evidence, a recommendation for primary prophylaxis of a first episode of OHE cannot be made in general. Only 2 studies have investigated the prevention of a first-time OHE episode as the primary endpoint. In this narrative review, we provide a concise overview of the current evidence levels on prediction tools and pharmacological prevention of a first episode of OHE. In addition, we give an outlook on future research targets to improve knowledge on this important topic.