Prognostic Implications of Minimal/Covert Hepatic Encephalopathy: Large-scale Validation Cohort Studies.

Minimal or Covert Hepatic Encephalopathy (MHE/CHE), the preclinical phase of Hepatic Encephalopathy (HE), is strongly associated with poorer Quality of Life (QOL), Overt HE (OHE), and death. Several diagnostic tests have been developed that have prognostic value in predicting clinical outcomes such as OHE, cirrhosis progression, and death. However, dispute among clinicians and HE researchers have kept its application largely underutilized. Current issues contributing to the confusion include: lack of a formal definition for CHE, uncertainty of which diagnostic tools to use, and whether one or two abnormal tests are required for a diagnosis. Due to this misunderstanding, the aims of this review were to consolidate large-scale (n ≥ 100) validation studies in order to discuss these obstacles and make recommendations for improving our approach to MHE/CHE. The studies included in this review are a great resource for initiating a unified effort for advancement in HE, and as such, it is our hope that this will drive progress toward common goals that will permanently improve the lives of patients with cirrhosis.

Diagnosis of covert hepatic encephalopathy: a multi-center study testing the utility of single versus combined testing.

Covert hepatic encephalopathy (CHE) affects cognition in a multidimensional fashion. Current guidelines recommend performing Psychometric Hepatic Encephalopathy Score (PHES) and a second test to diagnose CHE for multi-center trials. We aimed to determine if a two-test combination strategy improved CHE diagnosis agreement, and accuracy to predict overt hepatic encephalopathy (OHE), compared to single testing. Cirrhotic outpatients without baseline OHE performed PHES, Inhibitory Control Test (ICT), and Stroop EncephAlapp (StE) at three centers. Patients were followed for OHE development. Areas under the receiver operation characteristic curve (AUROC) were calculated. We included 437 patients (399 with follow-up data). CHE prevalence varied with testing strategy: PHES+ICT 18%, ICT + StE 25%, PHES+StE 29%, ICT 35%, PHES 37%, and StE 54%. Combination with best test agreement was PHES+StE (k = 0.34). Sixty patients (15%) developed OHE. Although CHE by StE showed the highest sensitivity to predict OHE, PHES and PHES+StE were more accurate at the expense of a lower sensitivity (55%, AUROC: 0.587; 36%, AUROC: 0.629; and 29%, AUROC: 0.623; respectively). PHES+ICT was the most specific (85%) but all strategies including ICT showed sensitivities in the 33-45% range. CHE diagnosis by PHES (HR = 1.79, p = 0.04), StE (HR = 1.69, p = 0.04), and PHES+StE (HR = 1.72, p = 0.04), were significant OHE predictors even when adjusted for prior OHE and MELD. Our results demonstrate that combined testing decreases CHE prevalence without improving the accuracy of OHE prediction. Testing with PHES or StE alone, or a PHES+StE combination, is equivalent to diagnose CHE and predict OHE development in a multi-center setting.

HCV core antigen as an alternative to HCV RNA testing in the era of direct-acting antivirals: retrospective screening and diagnostic cohort studies.

BACKGROUND: Direct-acting antivirals for chronic hepatitis C (HCV) infection have reduced the need for on-treatment HCV RNA monitoring. We assessed the accuracy and cost implications of using HCV core antigen testing to replace HCV RNA testing for confirmation of diagnosis, on-treatment monitoring, and determination of sustained virological response (SVR). METHODS: In a retrospective screening cohort study, de-identified residual serum from unselected samples were obtained from commercial laboratories in Ontario, Canada. Samples from each 5-year age-sex band from birth years 1945-74 collected from Aug 1, 2014, to Feb 28, 2015, were included. All samples that tested positive for HCV antibodies, and 10% of samples that tested negative for HCV antibodies, were tested for HCV core antigen and HCV RNA. A retrospective clinical cohort study was also done using blood samples from patients with confirmed HCV infection collected at four tertiary academic centres: one in Canada, two in Germany, and one in the USA. For assessment of SVR, we included samples from patients who started direct-acting antiviral-based treatment (excluding telaprevir and boceprevir) with or without peginterferon, ribavirin, or both, from Jan 1, 2014, to March 31, 2015. To ensure inclusion of adequate numbers for analysis, patients who relapsed after any treatment regimen were included. Serum samples included in the study were from baseline, week 4 on-treatment (only for patients treated with direct-acting antivirals), end of treatment, and week 12 or 24 of follow-up. The sensitivity and specificity of core antigen testing as a diagnostic tool was assessed in the screening cohort, using HCV RNA as a reference. The sensitivity and specificity of core antigen testing as well as its concordance with HCV RNA testing in the clinical cohort was assessed at baseline, week 4 on-treatment, and at weeks 12 or 24 after the end of treatment in patients undergoing therapy with direct-acting antivirals. The cost-effectiveness of core antigen testing with and without confirmatory HCV RNA testing for negative samples was also assessed. FINDINGS: From 10 006 samples in the screening cohort, 75 of 80 viraemic (HCV RNA-positive) samples tested positive for HCV core antigen (sensitivity 94%, 95% CI 86-98), and none of the 993 HCV RNA-negative samples tested positive for HCV core antigen (specificity 100%, 95% CI 94-100). The five viraemic samples that tested negative for HCV core antigen had low corresponding HCV RNA concentrations. In the clinical cohort, two (1%) of 202 baseline samples tested negative for HCV core antigen; one had a low HCV RNA concentration (468 IU/mL), the other had a high HCV RNA concentration (>2 000 000 IU/mL). By week 4 of treatment, HCV core antigen concentrations decreased in all patients but were not predictive of SVR. Although there was good concordance between HCV RNA and HCV core antigen results at 12 weeks after the end of treatment (r=0·97; p<0·0001), three of the 148 patients who achieved SVR at 12 weeks tested HCV core antigen positive. 12 weeks after the end of treatment, HCV core antigen was undetectable in one (1%) of 71 samples from patients who were identified as having relapsed according to HCV RNA detection. On-treatment and end-of-treatment testing of core antigen or HCV RNA provided little clinical value. The use of HCV core antigen testing as a confirmatory diagnostic strategy was cost saving relative to HCV RNA testing, with a reduction of CAD$0·29-3·70 per patient screened depending on whether HCV RNA testing was used to confirm HCV core antigen-negative results. INTERPRETATION: These data support the use of HCV core antigen testing to document HCV viraemia in a cost-saving diagnostic algorithm. In a treatment setting, HCV core antigen testing can be used instead of HCV RNA testing for diagnosis and documentation of treatment adherence, but it might not be adequate to determine SVR. This approach might improve access to care, particularly in low-income and middle-income countries. FUNDING: Abbott Diagnostics and Toronto Centre for Liver Disease.