Validation of the new 2021 EASL algorithm for the noninvasive diagnosis of advanced fibrosis in NAFLD

MASLD and MASH at the crossroads of hepatology trials and cardiorenal metabolic trials

Steatotic liver disease (SLD) is a worldwide public health problem, causing considerable morbidity and mortality. Patients with SLD are at increased risk for major adverse cardiovascular (CV) events, type 2 diabetes mellitus and chronic kidney disease. Conversely, patients with cardiometabolic conditions have a high prevalence of SLD. In addition to epidemiological evidence linking many of these conditions, there is evidence of shared pathophysiological processes. In December 2022, a unique multi-stakeholder, multi-specialty meeting, called MOSAIC (Metabolic multi Organ Science Accelerating Innovation in Clinical Trials) was convened to foster collaboration across metabolic, hepatology, nephrology and CV disorders. One of the goals of the meeting was to consider approaches to drug development that would speed regulatory approval of treatments for multiple disorders by combining liver and cardiorenal endpoints within a single study. Non-invasive tests, including biomarkers and imaging, are needed in hepatic and cardiorenal trials. They can be used as trial endpoints, to enrich trial populations, to diagnose and risk stratify patients and to assess treatment efficacy and safety. Although they are used in proof of concept and phase 2 trials, they are often not acceptable for regulatory approval of therapies. The challenge is defining the optimal combination of biomarkers, imaging and morbidity/mortality outcomes and ensuring that they are included in future trials while minimizing the burden on patients, trialists and trial sponsors. This paper provides an overview of some of the wide array of CV, liver and kidney measurements that were discussed at the MOSAIC meeting.

How effective are experienced hepatologists at staging fibrosis using non-invasive fibrosis tests in patients with metabolic dysfunction-associated steatotic liver disease?

BACKGROUND

Sequential use of non-invasive fibrosis tests (NITs) to identify patients with advanced hepatic fibrosis is recommended. However, it remains unclear how reliable clinicians are staging liver fibrosis using combinations of NITs.

AIM

Our aim was to assess concordance between NIT-based 'clinician fibrosis assessment (CFA)' and histology in patients with metabolic dysfunction-associated steatotic liver disease (MASLD) and compare this with established algorithmic approaches.

METHODS

Six experienced hepatologists independently staged 230 MASLD patients for advanced fibrosis (F0-2 vs F3-4) using FIB-4, FIB-4+ELF, FIB-4+ vibration controlled transient elastography (VCTE; Fibroscan™) and FIB-4+ELF+VTCE. Concordance between histology and CFA or algorithmic approaches were assessed.

RESULTS

A total of 230 patients were included (median age 54 [22-78] years; 55% female; median FIB-4 1.21 [IQR: 0.78-1.91]; ELF 9.3 [IQR: 8.6-10.2]; VCTE 9.4 [IQR: 6.3-14.3]; 41% F0-1, 22% F2, 21% F3 and 16% F4). Overall, area under the receiver operator curves for histologic F3-4 for the raw tests were 0.84 for FIB-4, 0.86 for ELF and 0.86 for VCTE. Concordance between the hepatologists was good (FIB4, κ = 0.64; FIB-4+ELF, κ = 0.70; FIB-4+VCTE, κ = 0.69; FIB-4+ELF+VCTE, κ = 0.70). Concordance between individual CFA and histology was variable, which was reflected in variability in sensitivity (44%-84%) and specificity (76%-94%). Concordance with histology was better when clinicians used NIT combinations. Purely algorithmic approaches, particularly sequential use of FIB-4 then VCTE, tended to perform better than the CFA.

CONCLUSIONS

Adhering to the recommended algorithmic approaches using NITs to stage fibrosis tended to perform more accurately than less-structured clinician NIT-based assessments conducted by experienced hepatologists.

The grade of obesity affects the noninvasive diagnosis of advanced fibrosis in individuals with MASLD

OBJECTIVE

Metabolic dysfunction-associated steatotic liver disease (MASLD) is closely associated with obesity. We aimed to assess the impact of obesity on the performance of different noninvasive tests, including liver stiffness measurement (LSM) and Agile3+ (A3+), to detect advanced fibrosis (AF) in a population of patients with MASLD encompassing a wide range of BMI values.

METHODS

A total of 479 patients with MASLD were consecutively included (Lyon Hepatology Institute). Clinical data and noninvasive tests, including FibroTest, LSM, A3+, Fibrosis-4 (FIB-4), magnetic resonance elastography, and liver biopsies, were collected. AF was determined by a composite endpoint, i.e., histological stage ≥ F3, overt diagnosis of cirrhosis by magnetic resonance elastography, or concordant LSM ≥ 9.6 kPa and FibroTest ≥ F3.

RESULTS

The median BMI was 35.0 kg/m2, and the prevalence of AF was 28.6%. Patients with BMI ≥ 35 versus <35 had a lower proportion of AF, i.e., 19.3% versus 38.1% (p < 0.001), but higher indeterminate status for AF (34.2% vs. 15.4%; p < 0.001). In the case of BMI ≥ 35, LSM had lower specificity to rule in AF (77.9%) versus A3+ (90.4%), but A3+ had decreased sensitivity to rule out AF. A sequential LSM/A3+ strategy achieved high specificity to rule in AF and lowered the proportion of indeterminate cases in patients with BMI ≥ 35.

CONCLUSIONS

The grade of obesity affects the detection of MASLD-related AF. A sequential use of LSM/A3+ could improve AF detection in patients with BMI ≥ 35.

Serum biomarkers for liver fibrosis assessment

Liver fibrosis is the result of chronic liver injury of different etiologies produced by an imbalance between the synthesis and degeneration of the extracellular matrix and dysregulation of physiological mechanisms. Liver has a high regenerative capacity in the early stage of chronic diseases so a prompt liver fibrosis detection is important. Consequently, an easy and economic tool that could identify patients with liver fibrosis at the initial stages is needed. To achieve this, many non-invasive serum direct, such as hyaluronic acid or metalloproteases, and indirect biomarkers have been proposed to evaluate liver fibrosis. Also, there have been developed formulas that combine these biomarkers, some of them also introduce clinical and/or demographic parameters, like FIB-4, non-alcoholic fatty liver disease fibrosis score (NFS), enhance liver fibrosis (ELF) or Hepamet fibrosis score (HFS). In this manuscript we critically reviewed different serum biomarkers and formulas for their utility in the diagnosis and progression of liver fibrosis.

Biomarcadores séricos para la evaluación de la fibrosis hepática

La fibrosis hepática se desarrolla como respuesta a la presencia de daño hepático crónico de diferentes etiologías, provocando un desequilibrio entre la síntesis y degeneración de la matriz extracelular y la desregulación de diversos mecanismos fisiológicos. En los estadios iniciales de las patologías crónicas, el hígado posee una elevada capacidad de regeneración, por lo que la detección temprana de la fibrosis hepática resulta esencial. En este contexto, es preciso contar con herramientas sencillas y económicas que permitan detectar la fibrosis hepática en sus fases iniciales. Para evaluar la fibrosis hepática, se han propuesto multitud de biomarcadores séricos no invasivos, tanto directos, como el ácido hialurónico o las metaloproteasas, como indirectos. Así mismo, se han desarrollado diversas fórmulas que combinan dichos biomarcadores junto con parámetros demográficos, como el índice FIB-4, el índice de fibrosis en la enfermedad de hígado graso no alcohólico (NFS, por sus siglas en inglés), la prueba ELF o el score de fibrosis Hepamet (HFS, por sus siglas en inglés). En el presente manuscrito, realizamos una revisión crítica del valor diagnóstico y pronóstico de los diferentes biomarcadores séricos y fórmulas actualmente existentes.

US-based Sequential Algorithm Integrating an AI Model for Advanced Liver Fibrosis Screening

Background Noninvasive tests can be used to screen patients with chronic liver disease for advanced liver fibrosis; however, the use of single tests may not be adequate. Purpose To construct sequential clinical algorithms that include a US deep learning (DL) model and compare their ability to predict advanced liver fibrosis with that of other noninvasive tests. Materials and Methods This retrospective study included adult patients with a history of chronic liver disease or unexplained abnormal liver function test results who underwent B-mode US of the liver between January 2014 and September 2022 at three health care facilities. A US-based DL network (FIB-Net) was trained on US images to predict whether the shear-wave elastography (SWE) value was 8.7 kPa or higher, indicative of advanced fibrosis. In the internal and external test sets, a two-step algorithm (Two-step#1) using the Fibrosis-4 Index (FIB-4) followed by FIB-Net and a three-step algorithm (Three-step#1) using FIB-4 followed by FIB-Net and SWE were used to simulate screening scenarios where liver stiffness measurements were not or were available, respectively. Measures of diagnostic accuracy were calculated using liver biopsy as the reference standard and compared between FIB-4, SWE, FIB-Net, and European Association for the Study of the Liver guidelines (ie, FIB-4 followed by SWE), along with sequential algorithms. Results The training, validation, and test data sets included 3067 (median age, 42 years [IQR, 33-53 years]; 2083 male), 1599 (median age, 41 years [IQR, 33-51 years]; 1124 male), and 1228 (median age, 44 years [IQR, 33-55 years]; 741 male) patients, respectively. FIB-Net obtained a noninferior specificity with a margin of 5% (P < .001) compared with SWE (80% vs 82%). The Two-step#1 algorithm showed higher specificity and positive predictive value (PPV) than FIB-4 (specificity, 79% vs 57%; PPV, 44% vs 32%) while reducing unnecessary referrals by 42%. The Three-step#1 algorithm had higher specificity and PPV compared with European Association for the Study of the Liver guidelines (specificity, 94% vs 88%; PPV, 73% vs 64%) while reducing unnecessary referrals by 35%. Conclusion A sequential algorithm combining FIB-4 and a US DL model showed higher diagnostic accuracy and improved referral management for all-cause advanced liver fibrosis compared with FIB-4 or the DL model alone. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Ghosh in this issue.

Non-invasive diagnosis of non-alcoholic fatty liver disease: Current status and future perspective

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease throughout the world. Hepatocellular carcinoma (HCC) and liver cirrhosis can result from nonalcoholic steatohepatitis (NASH), the severe stage of NAFLD progression. By some estimates, NAFLD affects almost one-third of the world's population, which is completely new and serious public health issue. Unfortunately, NAFLD is diagnosed by exclusion, and the gold standard for identifying NAFLD/NASH and reliably measuring liver fibrosis remains liver biopsy, which is an invasive, costly, time-consuming procedure and involves variable inter-observer diagnosis. With the progress of omics and imaging techniques, numerous non-invasive serological assays have been generated and developed. On the basis of these developments, non-invasive biomarkers and imaging techniques have been combined to increase diagnostic accuracy. This review provides information for the diagnosis and assessment of NAFLD/NASH in clinical practice going forward and may assist the clinician in making an early and accurate diagnosis and in proposing a cost-effective patient surveillance. We discuss newly identified and validated non-invasive diagnostic methods from biopsy-confirmed NAFLD patient studies and their implementation in clinical practice, encompassing NAFLD/NASH diagnosis and differentiation, fibrosis assessment, and disease progression monitoring. A series of tests, including 20-carboxy arachidonic acid (20-COOH AA) and 13,14-dihydro-15-keto prostaglandin D2 (dhk PGD2), were found to be potentially the most accurate non-invasive tests for diagnosing NAFLD. Additionally, the Three-dimensional magnetic resonance imaging (3D-MRE), combination of the FM-fibro index and Liver stiffness measurement (FM-fibro LSM index) and the machine learning algorithm (MLA) tests are more accurate than other tests in assessing liver fibrosis. However, it is essential to use bigger cohort studies to corroborate a number of non-invasive diagnostic tests with extremely elevated diagnostic values.

Algorithms for Early Detection of Silent Liver Fibrosis in the Primary Care Setting

More than one-third of the adult world population has steatotic liver disease (SLD), with a few percent of individuals developing cirrhosis after decades of silent liver fibrosis accumulation. Lack of systematic early detection causes most patients to be diagnosed late, after decompensation, when treatment has limited effect and survival is poor. Unfortunately, no isolated screening test in primary care can sufficiently predict advanced fibrosis from SLD. Recent efforts, therefore, combine several parameters into screening algorithms, to increase diagnostic accuracy. Besides patient selection, for example, by specific characteristics, algorithms include nonpatented or patented blood tests and liver stiffness measurements using elastography-based techniques. Algorithms can be composed as a set of sequential tests, as recommended by most guidelines on primary care pathways. Future use of algorithms that are easy to interpret, cheap, and semiautomatic will improve the management of patients with SLD, to the benefit of global health care systems.

Prolonged release pirfenidone pharmacokinetics is modified in cirrhosis GENESIS study

BACKGROUND

In both clinical and experimental trials, pirfenidone (PFD) showed anti-inflammatory and antifibrogenic effects. Considering the wide variation in hepatic functional reserve in patients with cirrhosis, we decided to learn more about the pharmacokinetics of a new formulation of prolonged release PFD in this population (PR-PFD), focusing on assessing changes on AUC0-∞, AUC0-t, and Cmax.

METHODS

In this study, 24 subjects with cirrhosis were included: eight subjects with mild liver impairment (Child-Pugh A) and eight with moderate liver impairment (Child-Pugh B), and a third group of eight age-matched subjects without fibrosis. All participants were under fasting conditions before receiving orally two 600-mg tablets of a prolonged-release formulation of pirfenidone (PR-PFD) and remained in the clinical unit for 36 h after PR-PFD administration. Serial blood samples were collected after dosing (0.5-36 h). A validated high-performance liquid chromatography-mass spectrometry method was used to determine PFD plasma concentrations.

RESULTS

The exposure to PR-PFD was 3.6- and 4.4-fold greater in subjects with Child-Pugh A and Child-Pugh B than in subjects without cirrhosis, and Cmax was 1.6- and 1.8-fold greater in subjects with Child-Pugh B and Child-Pugh-A than in patients without cirrhosis, without significant differences between the two cirrhotic groups. PFD was well tolerated.

CONCLUSION

The pharmacokinetic parameters of PR-PFD are significantly modified in patients with cirrhosis compared with those in controls, indicating that liver impairment should be considered in clinical practice.

Found in translation-Fibrosis in metabolic dysfunction-associated steatohepatitis (MASH)

Metabolic dysfunction-associated steatohepatitis (MASH) is a severe form of liver disease that poses a global health threat because of its potential to progress to advanced fibrosis, leading to cirrhosis and liver cancer. Recent advances in single-cell methodologies, refined disease models, and genetic and epigenetic insights have provided a nuanced understanding of MASH fibrogenesis, with substantial cellular heterogeneity in MASH livers providing potentially targetable cell-cell interactions and behavior. Unlike fibrogenesis, mechanisms underlying fibrosis regression in MASH are still inadequately understood, although antifibrotic targets have been recently identified. A refined antifibrotic treatment framework could lead to noninvasive assessment and targeted therapies that preserve hepatocellular function and restore the liver's architectural integrity.

Towards precision medicine in non-alcoholic fatty liver disease

Non-Alcoholic Fatty Liver Disease (NAFLD) refers to the accumulation of lipid laden vacuoles in hepatocytes, occurring in the context of visceral adiposity, insulin resistance and other features of the metabolic syndrome. Its more severe form (NASH, Non-Alcoholic Steatohepatitis) is becoming the leading aetiology of end-stage liver disease and hepatocellular carcinoma, and also contributes to cardiovascular disease, diabetes and extrahepatic malignancy. Management is currently limited to lifestyle modification and optimisation of the metabolic co-morbidities, with some of the drugs used for the latter also having shown some benefit for the liver. Licensed treatment modalities are currently lacking. A particular difficulty is the notorious heterogeneity of the patient population, which is poorly understood. A spectrum of disease severity associates in a non-linear way with a spectrum of severity of underlying metabolic factors. Heterogeneity of the liver in terms of mechanisms to cope with the metabolic and inflammatory stress and in terms of repair mechanisms, and a lack of knowledge hereof, further complicate the understanding of inter-individual variability. Genetic factors act as disease modifiers and potentially allow for some risk stratification, but also only explain a minor fraction of disease heterogeneity. Response to treatment shows a large variation in treatment response, again with little understanding of what is driving the absence of response in individual patients. Management can be tailored to patient's preferences in terms of diet modification, but tailoring treatment to knowledge on disease driving mechanisms in an individual patient is still in its infancy. Recent progress in analysing liver tissue as well as non-invasive tests hold, however, promise to rapidly improve our understanding of disease heterogeneity in NAFLD and provide individualised management.

Usefulness of controlled attenuation parameter in monitoring clinically relevant decline of hepatic steatosis for non-alcoholic fatty liver disease

BACKGROUND AND AIMS

Magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) is the reference standard of hepatic steatosis assessment. This study evaluates usefulness of controlled attenuation parameter (CAP) in monitoring the clinically relevant outcome by MRI-PDFF for non-alcoholic fatty liver disease (NAFLD) patients.

METHODS

NAFLD patients were enrolled prospectively. Instruction was given in lifestyle modifications with exercise and control of metabolic factors. MRI-PDFF and CAP were performed at enrollment and follow-up, with the diagnostic validity of CAP in monitoring clinically relevant outcome defined as a decline of ≥30% relative to baseline value by MRI-PDFF.

RESULTS

A total of 75 patients (male/female: 49/26, mean age: 53.2) were enrolled. Baseline MRI-PDFF, CAP and liver stiffness was 14.4%, 300.2 dB/m and 6.5 kPa. In a median interval of 369 days, thirteen (17.3%) patients achieved clinically relevant outcome with decline of 46.7 dB/m by CAP, compared with increase of 5.1 in the other patients. In multivariate analysis, clinically relevant outcome was associated with changes (Δ) of CAP and glucose. Assessed by area under receiver operating curve, the performances of ΔCAP in predicting clinically relevant outcome were 0.815 and 0.808, and with the specificity of >90%, the ΔCAP cutoff was -46 dB/m and -15% relative to baseline value; sensitivity was 53.8% and 46.2% with negative predictive value of 90.3% and 88.9% respectively.

CONCLUSIONS

For NAFLD patients, CAP exhibited good performance in monitoring clinically relevant decline of hepatic steatosis in MRI-PDFF. With the cutoffs of -46 dB/m or -15%, ΔCAP is useful in excluding clinical relevant outcome achievement.

Practical diagnosis of cirrhosis in non-alcoholic fatty liver disease using currently available non-invasive fibrosis tests

Unlike for advanced liver fibrosis, the practical rules for the early non-invasive diagnosis of cirrhosis in NAFLD remain not well defined. Here, we report the derivation and validation of a stepwise diagnostic algorithm in 1568 patients with NAFLD and liver biopsy coming from four independent cohorts. The study algorithm, using first the elastography-based tests Agile3+ and Agile4 and then the specialized blood tests FibroMeterV3G and CirrhoMeterV3G, provides stratification in four groups, the last of which is enriched in cirrhosis (71% prevalence in the validation set). A risk prediction chart is also derived to allow estimation of the individual probability of cirrhosis. The predicted risk shows excellent calibration in the validation set, and mean difference with perfect prediction is only -2.9%. These tools improve the personalized non-invasive diagnosis of cirrhosis in NAFLD.

Screening for NAFLD-Current Knowledge and Challenges

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of abnormal liver function tests worldwide, with an estimated prevalence ranging between 19-46% in the general population. Of note, NAFLD is also expected to become a leading cause of end-stage liver disease in the next decades. Given the high prevalence and severity of NAFLD, especially in high-risk populations (i.e., patients with type-2 diabetes mellitus and/or obesity), there is a major interest in early detection of the disease in primary care. Nevertheless, substantial uncertainties still surround the development of a screening policy for NAFLD, such as limitations in currently used non-invasive markers of fibrosis, cost-effectiveness and the absence of a licensed treatment. In this review, we summarise current knowledge and try to identify the limitations surrounding the screening policy for NAFLD in primary care.

Identification of high-risk subjects in nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is becoming the most common liver disease worldwide, and its burden is expected to increase due to the growing epidemic of obesity and diabetes. The key challenge among NAFLD patients is to identify those with advanced fibrosis (F3F4), who are at high risk of developing complications and will benefit from specialized management and treatment with new pharmacotherapies when they are approved. Liver biopsy appears unrealistic and unsuitable in practice, given the large number of high-risk patients and its well-known limitations. Non-invasive sequential algorithms using fibrosis-4 index as first-line test, followed by vibration-controlled transient elastography or patented blood test, are the best strategy for case finding of high-risk subjects. In fact, they are now recommended by several international guidelines, and should be used and disseminated to increase awareness among physicians beyond liver clinics where most NAFLD patients are seen.