The Performance of Vibration Controlled Transient Elastography in a US Cohort of Patients With Nonalcoholic Fatty Liver Disease

The Impact of Nonalcoholic Fatty Liver Disease in Primary Care: A Population Health Perspective

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of liver disease worldwide, with rising rates in parallel to those of obesity, type 2 diabetes, and metabolic syndrome. NAFLD encompasses a wide spectrum of pathology from simple steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis, which are linked to poor outcomes. Studies confirm a significant amount of undiagnosed NAFLD and related fibrosis within the community, increasing the overall burden of the disease. NAFLD appears to be more prevalent in certain populations, such as those with type 2 diabetes and metabolic syndrome. Early detection and lifestyle modifications, including weight loss and regular exercise, have been shown to improve outcomes. Adverse cardiovascular events are a key contributor to NAFLD-associated morbidity and mortality, and efforts to minimize their occurrence are essential. A targeted and algorithmic approach using noninvasive diagnostic techniques is promptly required to identify and risk-stratify patients with NAFLD. Patients at low risk of progression to NASH and advanced fibrosis can be managed in the primary care setting, while those at high risk of disease progression should be referred to hepatology specialists for surveillance and treatment. This review summarizes the key data of NAFLD's impact within primary care populations and proposes a potential algorithmic approach to identifying and managing such patients.

Nonalcoholic Fatty Liver Disease (NAFLD) for Primary Care Providers: Beyond the Liver

Abstract::

Nonalcoholic fatty liver disease (NAFLD) has consolidated as a major public health problem, affecting ~25% of the global population. This percentage is significantly higher in the setting of obesity and/or type 2 diabetes. Presence of NAFLD is associated with severe liver complications, such as nonalcoholic steatohepatitis (NASH; i.e., presence of inflammation and necrosis), cirrhosis and hepatocellular carcinoma. However, the majority of these patients die of cardiovascular disease. For this reason, management of this condition requires a multidisciplinary team, where primary care providers are at center stage. However, important misconceptions remain among primary care providers, preventing them from appropriately approach these patients. Nonalcoholic fatty liver disease should be understood as part of a systemic disease, characterized for abnormal accumulation of fat in tissues other than the adipose tissue. This, in turn, produces dysfunction of those organs or tissues (process sometimes referred to as lipotoxicity). Therefore, due to the systemic nature of this condition, it should not surprise that NAFLD is closely related to other metabolic conditions. In this review, we will focus on the extrahepatic manifestations of NAFLD and its metabolic and cardiovascular implications. We believe these are the most important issues primary care providers should understand, in order to effectively manage these complicated patients. In addition, we have provided a simple and straightforward approach to the diagnosis and treatment of patients with NAFLD and/or NASH. We hope this review will serve as a guide for primary care providers to approach their patients with NAFLD.

[Liver-specific diagnostic for non-alcoholic fatty liver disease (NAFLD) - time to replace liver biopsy?]

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases. In Germany, the prevalence in the adult population is estimated at 24 % and the incidence is increasing. Prognostically, the distinction between early and advanced stages of the disease is important. In particular, the extent of scarring considered as liver fibrosis is of prognostic significance. Patients with advanced fibrosis and cirrhosis show increased mortality. Liver fibrosis develops as a consequence of a persistent inflammation of the liver tissue over time. Since inflammation and fibrosis are histological features, liver biopsy is considered the reference method in the diagnosis of NAFLD. More recently, non-invasive diagnostic methods for staging (of fibrosis) and grading (activity) of the disease are being developed and validated. The current review summarizes new developments in non-invasive liver diagnostics.

Preferred Noninvasive Testing for Nonalcoholic Steatohepatitis

BACKGROUND

There has been an increased interest in the use of noninvasive tests (NITs) to identify advanced liver fibrosis in patients with nonalcoholic fatty liver disease (NALFD). The aim of our study was to define the change in tests' characteristics (sensitivity and specificity) of different combinations of NITs to detect advanced fibrosis in NAFLD.

METHODS

We stratified NITs into first and second tiers and compared two different strategies of combining NITs to screen for advanced fibrosis in patients with NAFLD. One strategy was using NITs in parallel, and the other was using NITs sequentially. Within both of these strategies, there were two ways of interpreting the overall results. The first way was called "the AND rule," where a positive result required both individual test results to be positive. The second way was called "the OR rule," where a positive result required only one individual test to be positive. Accuracy of NITs was obtained from the literature search. Combined accuracy and likelihood ratio (LR) were calculated.

RESULTS

Combination testing with parallel and sequential order testing under the AND Rule resulted in overall higher specificity and LR+ then using the NITs alone. Specificity ranged from 0.91 to 0.99, and LR+ from 9.3 to 68.6. The subsequent use of MRE was associated with LR+ between 36 and 69. Sensitivity was higher with parallel and sequential order testing under the OR Rule. LR+ ranged from 1.4 to 7.5, and sensitivity from 0.82 to 0.98.

CONCLUSION

Screening for advanced fibrosis should be performed sequentially, with positive results confirmed by additional testing. Specificity and LR+ were highest when MRE was employed as the confirmatory test.

Use of imaging techniques for non-invasive assessment in the diagnosis and staging of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease and represent a common finding in highly prevalent metabolic disorders (i.e. type 2 diabetes, metabolic syndrome, obesity). Non-alcoholic steatohepatitis (NASH) requires liver biopsy for grading and staging the liver damage by the assessment of steatosis, inflammation and fibrosis. In parallel with the development of numerous 'liquid' biomarkers and algorithms that combine anthropometric and laboratory parameters, innovative hepatic imaging techniques have increasingly been developed to attempt to overcome the need for biopsy, both in diagnosis and staging of NAFLD, and in possible use in the follow-up of the disease. In this review, we focused on the different imaging techniques trying to highlight the strengths and disadvantages of different approaches, particularly for ultrasound techniques, in stratifying liver injury and fibrosis in patients with NAFLD / NASH.

The role of noninvasive biomarkers in diagnosis and risk stratification in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronically elevated liver enzymes. Diagnosis and risk stratification of NAFLD remains clinically challenge as patients with NAFLD are either asymptomatic or have nonspecific presenting complaints and may have normal liver enzymes. Nonalcoholic steatohepatitis (NASH), the clinically aggressive variant of NAFLD, is also difficult to differentiate noninvasively, and a liver biopsy is required to definitively diagnose NASH. Thus, the definitive diagnosis and risk stratification of NAFLD is embedded in histological assessment of the liver. Several clinical aides been investigated in an attempt to risk stratify and identify patients noninvasively as doing a liver biopsy in all patients with NAFLD are not feasible. Since these biomarkers are unable to differentiate NASH from non-NASH, they have leveraged biochemical changes within the liver as patients progress to varying degree of hepatic fibrosis to identify patients with moderate fibrosis (fibrosis stage 2 or greater) and advanced fibrosis (fibrosis stage 3 or greater) to help guide the need for additional and more definitive workup. These clinical aides span from by-products of apoptosis to statistical modelling of clinically available data to identify 'at-risk' patients with NAFLD. The current review will focus the diagnostic performance of these noninvasive serum-based biomarkers in NAFLD.

Assessment of hepatic fibrosis and steatosis by vibration-controlled transient elastography and controlled attenuation parameter versus non-invasive assessment scores in patients with non-alcoholic fatty liver disease

Background

Non-alcoholic fatty liver disease (NAFLD) is regarded as the most common liver disease in the twenty-first century, and a condition leaving individuals at increased risk of extra-hepatic morbidity. Liver biopsy has long been regarded as the gold standard for diagnosis and prognostication of patients with NAFLD. However, due to its invasive nature and potential complications (e.g., bleeding), other methods for non-invasive laboratory and radiological assessment of hepatic steatosis and fibrosis in NAFLD have evolved and include scores such as AST/Platelet Ratio Index (APRI), Fibrosis-4 (FIB-4) score, NAFLD fibrosis score (NFS), and fatty liver index (FLI), in addition to radiological methods such as transient elastography (TE), which is a well-validated non-invasive ultrasound-based technique for assessment of hepatic fibrosis. Recently, novel development of controlled attenuation parameter (CAP) in TE allowed simultaneous assessment of hepatic steatosis. This provided a chance to assess both hepatic fibrosis and steatosis in the same setting and without any unwanted complications. This study aimed at assessing the role of TE and CAP versus other non-invasive assessment scores for liver fibrosis and steatosis in patients with NAFLD.

Results

This study included 90 patients diagnosed with NAFLD based on abdominal ultrasonography, body mass index, and serum liver enzymes. All patients were assessed with TE and non-invasive scores (APRI score, FIB-4 score, NFS, and FLI). There was a highly significant positive correlation between fibrosis and steatosis grades assessed by TE and other non-invasive respective scores. Both TE and CAP achieved acceptable sensitivity and specificity compared to other non-invasive assessment methods.

Conclusions

TE with CAP can be used as a screening method for patients suspected with NAFLD or patients without a clear indication for liver biopsy. CAP allows a non-invasive method of assessment of hepatic steatosis in patients with NAFLD.

Clinical assessment for high-risk patients with non-alcoholic fatty liver disease in primary care and diabetology practices

BACKGROUND

Primary care practitioners (PCPs) and diabetologists are at the frontline of potentially encountering patients with NASH. Identification of those at high risk for adverse outcomes is important.

AIM

To provide practical guidance to providers on how to identify these patients and link them to specialty care.

METHODS

US members of the Global Council on NASH evaluated the evidence about NASH and non-invasive tests and developed a simple algorithm to identify high-risk NASH patients for diabetologists and primary care providers. These tools can assist frontline providers in decision-making and referral to gastroenterology/hepatology practices for additional assessments.

RESULTS

The presence of NASH-related advanced fibrosis is an independent predictor of adverse outcomes. These patients with NASH are considered high risk and referral to specialists is warranted. Given that staging of fibrosis requires a liver biopsy, non-invasive tests for fibrosis would be preferred. Consensus recommendation from the group is to risk-stratify patients based on metabolic risk factors using the FIB-4 as the initial non-invasive test due to its simplicity and ease of use. A FIB-4 score ≥1.3 can be used for further assessment and linkage to specialty care where additional technology to assess liver stiffness or serum fibrosis test will be available.

CONCLUSION

Due to the growing burden of NAFLD and NASH, PCPs and diabetologists are faced with increased patient encounters in their clinical practices necessitating referral decisions. To assist in identifying high-risk NASH patients requiring specialty care, we provide a simple and easy to use algorithm.

Liver Phenotypes of European Adults Heterozygous or Homozygous for Pi∗Z Variant of AAT (Pi∗MZ vs Pi∗ZZ genotype) and Noncarriers

BACKGROUND & AIMS

Homozygosity for the Pi∗Z variant of the gene that encodes the alpha-1 antitrypsin peptide (AAT), called the Pi∗ZZ genotype, causes a liver and lung disease called alpha-1 antitrypsin deficiency. Heterozygosity (the Pi∗MZ genotype) is a risk factor for cirrhosis in individuals with liver disease. Up to 4% of Europeans have the Pi∗MZ genotype; we compared features of adults with and without Pi∗MZ genotype among persons without preexisting liver disease.

METHODS

We analyzed data from the European Alpha-1 Liver Cohort, from 419 adults with the Pi∗MZ genotype, 309 adults with the Pi∗ZZ genotype, and 284 individuals without the variant (noncarriers). All underwent a comprehensive evaluation; liver stiffness measurements (LSMs) were made by transient elastography. Liver biopsies were analyzed to define histologic and biochemical features associated with the Pi∗Z variant. Levels of serum transaminases were retrieved from 444,642 participants, available in the United Kingdom biobank.

RESULTS

In the UK biobank database, levels of serum transaminases were increased in subjects with the Pi∗MZ genotype compared with noncarriers. In the Alpha-1 Liver Cohort, adults with Pi∗MZ had lower levels of gamma-glutamyl transferase in serum and lower LSMs than adults with the Pi∗ZZ variant, but these were higher than in noncarriers. Ten percent of subjects with the Pi∗MZ genotype vs 4% of noncarriers had LSMs of 7.1 kPa or more (adjusted odds ratio, 4.8; 95% confidence interval, 2.0-11.8). Obesity and diabetes were the most important factors associated with LSMs ≥7.1 kPa in subjects with the Pi∗MZ genotype. AAT inclusions were detected in liver biopsies of 63% of subjects with the Pi∗MZ genotype, vs 97% of subjects with the Pi∗ZZ genotype, and increased with liver fibrosis stages. Subjects with the Pi∗MZ genotype did not have increased hepatic levels of AAT, whereas levels of insoluble AAT varied among individuals.

CONCLUSIONS

Adults with the Pi∗MZ genotype have lower levels of serum transaminases, fewer AAT inclusions in liver, and lower liver stiffness than adults with the Pi∗ZZ genotype, but higher than adults without the Pi∗Z variant. These findings should help determine risk of subjects with the Pi∗MZ genotype and aid in counseling.

Correlation between the small dense LDL level and nonalcoholic fatty liver disease: Possibility of a new biomarker

Small dense low-density lipoprotein (sdLDL) is a distinct low-density lipoprotein (LDL) cholesterol subclass that has been reported to be associated with metabolic disease. On the other hand, the relationship between the sdLDL level and the nonalcoholic fatty liver disease (NAFLD) severity is unclear. In this study, the sdLDL level was measured in patients with NAFLD to assess its potential as a biomarker for evaluating NAFLD. One hundred and twenty-six patients diagnosed with NAFLD at a single referral hospital from January 2018 to August 2019 were enrolled. The lipoprotein profile was analyzed from a blood test of NAFLD patients, and transient elastography (TE, Fibroscan) was performed to evaluate the degree of NAFLD. Among the 126 patients, 83 patients that could confirm the lipoprotein profile and TE results were finally enrolled in the study. The controlled attenuation parameter (CAP) value obtained from TE did not show any correlation with the total cholesterol, LDL. But, the sdLDL level showed a significant positive correlation with the CAP value (r = 0.237, P = .031), and the sdLDL/LDL ratio also showed a significant positive correlation with the CAP value (r = 0.235, P = .032). The liver stiffness (LS) measured by TE and the sdLDL level were positively correlated in patients with NAFLD (rho = 0.217, P = .049). The sdLDL/LDL ratio also showed a significant positive correlation with the LS value (rho = 0.228, P = .038). In addition, the fatty liver index also showed a significant positive correlation with the sdLDL/LDL ratio (r = 0.448, P = .000). In this study, the sdLDL level measured by a blood test of NAFLD patients showed a positive correlation with the CAP value and LS, which indicate the degree of hepatic steatosis and fibrosis. These results suggest the possibility of the sdLDL level as a new biomarker of NAFLD, but further studies will be needed to support these results.

The Role of Multiparametric US of the Liver for the Evaluation of Nonalcoholic Steatohepatitis

Background Nonalcoholic steatohepatitis (NASH) is diagnosed with histopathologic testing, but noninvasive surrogate markers are desirable for screening patients who are at high risk of NASH. Purpose To investigate the diagnostic performance of dispersion slope, attenuation coefficient, and shear-wave speed measurements obtained using two-dimensional (2D) shear-wave elastography (SWE) in assessing inflammation, steatosis, and fibrosis and in the noninvasive diagnosis of NASH in patients suspected of having nonalcoholic fatty liver disease (NAFLD). Materials and Methods This prospective study collected data from 120 consecutive adults who underwent liver biopsy for suspected NAFLD and were enrolled between April 2017 and March 2019. Three US parameters (dispersion slope [(m/sec)/kHz], attenuation coefficient [dB/cm/MHz], and shear-wave speed [in meters per second]) were measured using a 2D SWE system immediately before biopsy. The biopsy specimens were scored by one expert pathologist according to the Nonalcoholic Steatohepatitis Clinical Research Network criteria (119 participants underwent a histologic examination). Diagnostic performance was assessed using the area under the receiver operating characteristic curve (AUC) for the categories of inflammation, steatosis, and fibrosis. Results One hundred eleven adults (mean age, 53 years ± 18 [standard deviation]; 57 men) underwent a US examination. Dispersion slope enabled the identification of lobular inflammation, with an AUC of 0.95 (95% confidence interval [CI]: 0.91, 0.10) for an inflammation grade greater than or equal to A1 (mild), 0.81 (95% CI: 0.72, 0.89) for an inflammation grade greater than or equal to A2 (moderate), and 0.85 (95% CI: 0.74, 0.97) for an inflammation grade equal to A3 (marked). Attenuation coefficient enabled the identification of steatosis, with an AUC of 0.88 (95% CI: 0.80, 0.97) for steatosis grade greater than or equal to S1 (mild), 0.86 (95% CI: 0.79, 0.93) for steatosis grade greater than or equal to S2 (moderate), and 0.79 (95% CI: 0.68, 0.89) for steatosis grade equal to S3 (severe). Shear-wave speed enabled the identification of fibrosis, with an AUC of 0.79 (95% CI: 0.69, 0.88) for fibrosis stage greater than or equal to F1 (portal fibrosis), 0.88 (95% CI: 0.82, 0.94) for fibrosis stage greater than or equal to F2 (periportal fibrosis), 0.90 (95% CI: 0.84, 0.96) for fibrosis stage greater than or equal to F3 (septal fibrosis), and 0.95 (95% CI: 0.91, 0.99) for fibrosis stage equal to F4 (cirrhosis). The combination of dispersion slope, attenuation coefficient, and shear-wave speed showed an AUC of 0.81 (95% CI: 0.71, 0.91) for the diagnosis of NASH. Conclusion Dispersion slope, attenuation coefficient, and shear-wave speed were found to be useful for assessing lobular inflammation, steatosis, and fibrosis, respectively, in participants with biopsy-proven nonalcoholic fatty liver disease. © RSNA, 2020 Online supplemental material is available for this article.

Nonalcoholic fatty liver disease and type 2 diabetes: where do Diabetologists stand?

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. The increasing prevalence of NAFLD mirrors that of obesity and type 2 diabetes over the last two decades.

MAIN

In a two-way pathophysiologic relationship, NAFLD increases the risk of developing type 2 diabetes, while the latter promotes the progression of simple fatty liver to a more advanced form called nonalcoholic steatohepatitis (NASH). NASH increases the risk of cirrhosis and hepatocellular carcinoma (HCC), which may require liver transplantation. With the absence of FDA-approved medications for NAFLD treatment, lifestyle intervention remains the only therapy. Lately, extensive research efforts have been aimed at modifying NASH fibrosis and developing noninvasive screening methods.

CONCLUSION

We highlight the pathophysiologic relationships between NAFLD and type 2 diabetes, discuss disease recognition, models of care, and current and emerging therapies for NASH treatment.

Accuracy of the Enhanced Liver Fibrosis test, and combination of the Enhanced Liver Fibrosis and non-invasive tests for the diagnosis of advanced liver fibrosis in patients with non-alcoholic fatty liver disease

AIM

The Enhanced Liver Fibrosis (ELF) test comprises a logarithmic algorithm combining three serum markers of hepatic extracellular matrix metabolism. We aimed to evaluate the performance of ELF for the diagnosis of liver fibrosis and to compare it with that of liver stiffness measurement (LSM) by FibroScan in non-alcoholic fatty liver disease.

METHODS

ELF cut-off values for the diagnosis of advanced fibrosis were obtained using receiver operating characteristic analysis in patients with biopsy-confirmed non-alcoholic fatty liver disease (training set; n = 200). Diagnostic performance was analyzed in the training set and in a validation set (n = 166), and compared with that of LSM in the FibroScan cohort (n = 224).

RESULTS

The area under receiver operating characteristic curve was 0.81 for the diagnosis of advanced fibrosis, and the ELF cut-off values were 9.34 with 90.4% sensitivity and 10.83 with 90.6% specificity in the training set, and 89.8% sensitivity and 85.5% specificity in the validation set. There was no significant difference in the area under the receiver operating characteristic curve between ELF and LSM (0.812 and 0.839). A combination of ELF (cut-off 10.83) and LSM (cut-off 11.45) increased the specificity to 97.9% and the positive predictive value, versus ELF alone. Sequential use of the Fibrosis-4 index (cut-off 2.67) and ELF (cut-off 9.34) increased the sensitivity to 95.9%.

CONCLUSIONS

ELF can identify advanced liver fibrosis in non-alcoholic fatty liver disease, and its diagnostic accuracy is comparable to that of FibroScan. According to the clinical setting, combinations or sequential procedures using other non-invasive tests complement the diagnostic performance of ELF for the identification of advanced fibrosis.

When the liver gets stiff, the tough get moving

Liver stiffness measurement (LSM) by FibroScan-determined transient elastography is a noninvasive approach to estimate liver fibrosis severity. In non-alcoholic fatty liver disease (NAFLD), advanced liver fibrosis is excluded by normal liver stiffness, but a wide range of cutoffs have been used to predict advanced liver fibrosis or cirrhosis. This may be partly because steatosis (measured by controlled attenuation parameter [CAP]) contributes to liver stiffness and also because LSM fluctuates in NAFLD. In a recent pivotal study, one-third of patients with liver stiffness > 12.0 kPa showed reversal after 4-6 months; these cases did not have advanced liver fibrosis on biopsy. We performed serial FibroScans 6-36 months apart in 73 NAFLD patients, 38 with LSM > 10 kPa at entry. Those who lost ≥ 1 kg of weight (n = 31) significantly reduced liver stiffness (3.6 ± 6.1 vs 0.53 ± 4.1 kPa, P < 0.05) and CAP score (39 ± 63 dB/m of loss vs 24 ± 65 dB/m of gain, P < 0.05) compared with those who did not (n = 29). Patients who reported increased physical activity (n = 25) also reduced liver stiffness (3.6 ± 6 vs 0.35 ± 6 kPa) and CAP (20 ± 71 dB/m of loss vs 32 ± 71 dB/m of gain). Overall, those with improved LSM were significantly more likely to have lost weight and/or improved physical activity. These effects of lifestyle adjustments partly explain why a single measurement of 12.0 kPa is not a reliable cutoff for advanced liver fibrosis in NAFLD. In addition to repeating the study after 6-12 months, documentation of response to lifestyle advice and weight reduction should be determined before assuming any cutoff indicates advanced liver fibrosis. Despite this reservation about diagnostic accuracy, we consider that measurement of liver stiffness and CAP score serve to motivate patients to enact lifestyle modifications that can improve NAFLD severity.

Nonalcoholic Fatty Liver Disease: What Does the Primary Care Physician Need to Know?

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the United States and is soon to be the leading cause of liver transplantation. Patients at the greatest risk are those with obesity and type 2 diabetes mellitus. In 2019 the American Diabetes Association guidelines called, for the first time, for clinicians to screen for steatohepatitis and fibrosis all patients with type 2 diabetes and liver steatosis or abnormal plasma aminotransferases. This requires primary care physicians to be aware of key aspects related to the diagnosis and treatment of NAFLD, as well as to when to refer to a specialist. Unfortunately, there is still significant medical inertia as clinicians remain unaware of its high morbidity/mortality. Early diagnosis in the primary care setting is critical to prevent progression to end-stage liver disease. Patients with NAFLD are also at a higher risk of developing type 2 diabetes mellitus and cardiovascular disease. Despite general perception to the contrary, weight loss by lifestyle intervention or bariatric surgery and several pharmacological treatments (eg, vitamin E in nondiabetics, pioglitazone or glucagon-like peptide 1 receptor agonists in patients with or without diabetes) can often be successful to reverse steatohepatitis and prevent disease progression.

Nonalcoholic Fatty Liver Disease 2020: The State of the Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease, with a worldwide prevalence of 25%. In the United States, NAFLD and its subtype, nonalcoholic steatohepatitis, affect 30% and 5% of the population, respectively. Considering the ongoing obesity epidemic beginning in childhood, the rise in diabetes, and other factors, the prevalence of NAFLD along with the proportion of those with advanced liver disease is projected to continue to increase. This will have an important impact on public health reflected in health care costs, including impact on the need for liver transplantation, for which nonalcoholic steatohepatitis is already close to becoming the most common indication. NAFLD patients with evidence of nonalcoholic steatohepatitis and advanced fibrosis are at markedly increased risk of adverse outcomes, including overall mortality, and liver-specific morbidity and mortality, respectively. Identification of this cohort of NAFLD patients is paramount, given the associated poorer outcomes, in order to target resources to those who need it most. Various noninvasive tools have been developed in this regard. This review provides an update on the epidemiology, clinical and prognostic features, and diagnostic approach to patients with NAFLD.

Noninvasive Diagnosis of NAFLD and NASH

The aim of this review is to outline emerging biomarkers that can serve as early diagnostic tools to identify patients with nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) and, among them, the subgroup of best candidates for clinical trials on emerging compounds. Regarding possible predictors of NAFLD, a number of studies evaluated a combination of serum biomarkers either available in routine practice (or investigational) or proprietary and expensive. So far, magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) appears to be the most accurate for fatty liver diagnosis. In clinical practice, the main question is how to diagnose NASH early. There are new promising biomarkers that can help in diagnosing early stages of NASH, yet they include variables not routinely tested. In the setting of NASH, most studies confirm that, in spite of several well-known limitations, transient elastography or point shear wave elastography can help in enriching the pool of patients that should be screened for investigational treatments. Newer multiomics biomarkers including those focusing on microbiota can be useful but require methods to be standardized and implemented. To date, one biomarker alone is not able to non- or minimally invasively identify patients with NASH and mild to moderate fibrosis.

How to Identify the Patient with Nonalcoholic Steatohepatitis Who Will Progress to Cirrhosis

Non-alcoholic fatty liver disease (NAFLD) figures prominently into the clinical hepatology landscape. NAFLD represents a disease spectrum comprising simple steatosis, steatosis with elevated liver enzymes, and non-alcoholic steatohepatitis (NASH), the entity with clear potential for fibrosis progression. Risk factors associated with fibrosis progression in NASH include histologic findings of lobular inflammation and any fibrosis as well as clinical comorbidities that include type 2 diabetes, obesity, and metabolic syndrome. Liver biopsy remains the gold standard in evaluating NASH; however, noninvasive methods are accumulating evidence for a growing role in identifying patients at increased risk to develop NASH, fibrosis, and potentially cirrhosis.

Recruitment and Retention of Patients for Nonalcoholic Steatohepatitis Clinical Trials

The volume of clinical studies globally in nonalcoholic fatty liver disease has created tremendous competition among sponsors and investigators to identify patients. Patients with nonalcoholic steatohepatitis are often asymptomatic and personally unaware and uneducated about the disease. In addition, many physicians caring for undiagnosed patients are also poorly informed of the disease. This has created a perfect storm of high demand for clinical research participants among a pool of difficult to identify patients with nonalcoholic steatohepatitis. Based on the current data, the current volume of nonalcoholic fatty liver disease studies requires 13,049 patients to fulfill their patient enrollment requirements.

The Role of Noninvasive Tests for Differentiating NASH From NAFL and Diagnosing Advanced Fibrosis Among Patients With NAFLD

Assessing for the presence of non-alcoholic steatohepatitis (NASH) and the presence of advanced fibrosis is vital among patients with non-alcoholic fatty liver disease (NAFLD) as each is predictive of disease outcomes. A liver biopsy is the gold standard method for doing so but is impossible to perform among all patients with NAFLD. Reliable methods for noninvasively detecting for the presence of NASH and advanced fibrosis are thus a pressing need. The search for noninvasive tests has been more successful for advanced fibrosis than for NASH. Clinical prediction models and elastography have acceptable accuracy for ruling out advanced fibrosis; when used together, as in a fibrosis prediction algorithm presented in this review, it can avoid the need for liver biopsy among many patients with NAFLD. Several biomarkers for identifying the presence of NASH have been studied but none are sufficiently accurate or validated. Of those studied, the most promising include CK-18 fragments, lipodomic and metabolomics candidates, and magnetic resonance elastography with proton density fat fraction. However, none are ready for clinical use and ultimately large multicenter prospective cohort studies are needed to validate select novel biomarkers.

Free fatty acid-based low-impedance liver image: a characteristic appearance in nonalcoholic steatohepatitis (NASH)

Background

To examine in vitro acoustic property of nonalcoholic fatty disease in mouse and human liver to identify nonalcoholic steatohepatitis (NASH).

Methods

The acoustic impedance (× 10⁶ kg/m²/s) was measured in 35 free fatty acids (FFAs, 500 mmol/L) and histologically-diagnosed liver samples of twelve mice (four control, four simple steatosis [SS], and four NASH) and eight humans (two control, three SS, and three NASH), using 80-MHz acoustic microscopy. The sum of percentage (SP) composition of FFAs (SP-FFAs) was also assessed.

Results

Median impedance of all FFAs was 0.7 (5 FFAs with impedance 0.7); 17 FFAs with impedance < 0.7 were classified as low-impedance group; and, 13 FFAs with impedance > 0.7 were classified as high-impedance group. The median impedance of the mouse liver decreased from control (1.715), to SS (1.68), to NASH (1.635) (control versus NASH, p = 0.039 without significant differences for the other comparisons, p ≥ 0.1). Similarly, the median impedance of human liver showed decreased from control (1.825), to SS (1.788), to NASH (1.76) (control versus SS, p = 0.023; control versus NASH, p = 0.003; SS versus NASH, p = 0.050). The ratio of SP-FFAs between the low-impedance and high-impedance groups showed an increase in both mice and humans, with significant differences in mice (control versus SS, p < 0.001; control versus NASH, p < 0.001; SS versus NASH, p = 0.003), without significant differences in humans (p ≥ 0.671).

Conclusion

Lower acoustic impedance based on the intrahepatic composition of FFAs may be characteristic of NASH.

Liver fibrosis imaging: A clinical review of ultrasound and magnetic resonance elastography

Liver fibrosis is a histological hallmark of most chronic liver diseases, which can progress to cirrhosis and liver failure, and predisposes to hepatocellular carcinoma. Accurate diagnosis of liver fibrosis is necessary for prognosis, risk stratification, and treatment decision-making. Liver biopsy, the reference standard for assessing liver fibrosis, is invasive, costly, and impractical for surveillance and treatment response monitoring. Elastography offers a noninvasive, objective, and quantitative alternative to liver biopsy. This article discusses the need for noninvasive assessment of liver fibrosis and reviews the comparative advantages and limitations of ultrasound and magnetic resonance elastography techniques with respect to their basic concepts, acquisition, processing, and diagnostic performance. Variations in clinical contexts of use and common pitfalls associated with each technique are considered. In addition, current challenges and future directions to improve the diagnostic accuracy and clinical utility of elastography techniques are discussed. Level of Evidence: 5 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:25-42.

Discordant pathological diagnosis of non-alcoholic fatty liver disease: A prospective multicenter study

Background

Liver biopsy has been the standard procedure for diagnosing and evaluating the severity of non‐alcoholic fatty liver disease (NAFLD) and non‐alcoholic steatohepatitis (NASH); however, interobserver discordance remains a critical issue in its pathological diagnosis.

Methods and Results

We examined the concordance rates of pathological scoring and diagnosis between pathologists at individual institutions (local diagnosis) and two central pathologists specialized in liver pathology (central diagnosis). A total of 150 patients with NAFLD underwent prospective liver biopsies. NAFLD activity score (NAS) and fibrosis stage were evaluated, and NASH was determined according to Matteoni's classification. NAS, scores for all NAS components, and fibrosis stage were diagnosed at a lower degree by central compared with local diagnosis. NASH was diagnosed in 34% of the patients according to central pathologists compared with 54% according to local pathologists (P < 0.001). The concordance rates for NAS, steatosis, inflammation, ballooning, fibrosis, and NASH diagnosis were 26.7, 62.7, 51.3, 48.7, 43.3, and 50.7%, respectively. The correlation coefficient between local and central diagnoses was the lowest for the scoring of ballooning (ρ = 0.218).

Conclusion

Concordance rates among pathologists for the evaluation of NAFLD are currently poor, and simple and reliable diagnostic and evaluation criteria are urgently needed to improve the clinical management of NAFLD patients.

Noninvasive Tests Accurately Identify Advanced Fibrosis due to NASH: Baseline Data From the STELLAR Trials

Accurate noninvasive tests (NITs) are needed to replace liver biopsy for identifying advanced fibrosis caused by nonalcoholic steatohepatitis (NASH). We analyzed screening data from two phase 3 trials of selonsertib to assess the ability of NITs to discriminate advanced fibrosis. Centrally read biopsies from the STELLAR studies, which enrolled patients with bridging fibrosis and compensated cirrhosis, were staged according to the NASH Clinical Research Network classification. We explored associations between fibrosis stage and NITs, including the nonalcoholic fatty liver disease fibrosis score (NFS), fibrosis-4 (FIB-4) index, Enhanced Liver Fibrosis (ELF) test, and liver stiffness by vibration-controlled transient elastography (LS by VCTE). The performance of these tests to discriminate advanced fibrosis, either alone or in combinations, was evaluated using areas under the receiver operating characteristic curve (AUROCs) with 5-fold cross-validation repeated 100 times. Of the 4,404 patients screened for these trials, 3,202 had evaluable biopsy data: 940 with F0-F2 fibrosis and 2,262 with F3-F4 fibrosis. Significant differences between median values of NITs for patients with F0-F2 versus F3-F4 fibrosis were observed: -0.972 versus 0.318 for NFS, 1.18 versus 2.20 for FIB-4, 9.22 versus 10.39 for ELF, and 8.8 versus 16.5 kPa for LS by VCTE (all P < 0.001). AUROCs ranged from 0.75 to 0.80 to discriminate advanced fibrosis. FIB-4 followed by an LS by VCTE or ELF test in those with indeterminate values (FIB-4 between 1.3 and 2.67) maintained an acceptable performance while reducing the rate of indeterminate results. Conclusion: Among patients being considered for enrollment into clinical trials, NITs alone or in combination can reduce the need for liver biopsy to discriminate advanced fibrosis caused by NASH. The predictive value of these tests for general screening will require confirmation in a real-world population.

Different predictors of steatosis and fibrosis severity among lean, overweight and obese patients with nonalcoholic fatty liver disease

BACKGROUNDS

Non-obese nonalcoholic fatty liver disease (NAFLD) is paradoxically associated with improved metabolic and pathological features at diagnosis but worse prognosis relative to obese NAFLD.

AIM

To compare predictors of disease severity in NAFLD with different body mass index (BMI) categories.

METHODS

All 1509 consecutive NAFLD patients were classified as lean (20.2%), overweight (23.1%) and obese (56.7%). Liver fat content (LFC) and fibrosis were estimated with magnetic resonance imaging-based proton density fat fraction and shear wave elastography respectively.

RESULTS

Lipid profiles and uric acid (UA) were significantly increased in parallel with BMI categories (pairwise comparison P < 0.001), but insulin resistance (IR) was significantly different between the non-obese and obese groups. For LFC ≥ 10%, increased waist circumference (WC) was an independent predictor in all groups, while UA elevation (P = 0.02) was predictive in the overweight patients, but BMI ≥ 28 kg/m² (P = 0.029) and IR (P = 0.026) were significant in the obese patients. For fibrosis, alanine aminotransferase (ALT) > 40 U/L (P = 0.031), increased WC (P = 0.012) and BMI ≥ 28 kg/m² (P < 0.001) plus ALT > 40 U/L (P = 0.007) were predictors in the lean, overweight and obese patients, respectively.

CONCLUSIONS

WC was strongly predictive of disease severity in all NAFLD, while UA and BMI plus IR were additional predictors in the overweight and obese NAFLD respectively. Individualized screening strategies should be established for NAFLD according to different BMIs.

Impact of Implementing a "FIB-4 First" Strategy on a Pathway for Patients With NAFLD Referred From Primary Care

Detection of advanced fibrosis in nonalcoholic fatty liver disease (NAFLD) is essential for stratifying patients according to the risk of liver‐related morbidity. Noninvasive methods such as vibration‐controlled transient elastography (VCTE) and Fibrosis‐4 index (FIB‐4) have been recommended to identify patients for further assessment. The aim of this study was to assess the potential impact of implementing a “FIB‐4 First” strategy to triage patients entering a NAFLD assessment pathway. The pathway for patients with suspected NAFLD was piloted at a tertiary liver center. Referral criteria were 16‐65 years old, elevated alanine aminotransferase and/or steatosis on imaging, and absence of a previous liver diagnosis. A registered nurse risk‐stratified all patients based on VCTE and FIB‐4 was calculated. Potential alternative diagnoses were excluded with bloodwork. A total of 565 patients underwent risk stratification with VCTE with a 97% success rate. Ten percent had VCTE of at least 8 kPa; 560 patients had FIB‐4 available for analysis and 87% had values less than 1.3. Of those with a FIB‐4 of at least 1.3, 69% had a VCTE less than 8 kPa. Further modeling showed that the presence of diabetes, age, and body mass index had only a moderate impact on the association between FIB‐4 and elastography values if using a FIB‐4 threshold of 1.3. Conclusion: A FIB‐4 threshold of 1.3 was acceptable for excluding the presence of advanced fibrosis (assessed by VCTE). A staged risk‐stratification model using FIB‐4 and VCTE could save up to 87% of further assessments. This model could improve accessibility by moving the initial fibrosis evaluation to the medical home and helping to prioritize patients for further specialized care.

Evaluation and comparison of six noninvasive tests for prediction of significant or advanced fibrosis in nonalcoholic fatty liver disease

Background

In nonalcoholic fatty liver disease (NAFLD), advanced fibrosis has been identified as an important prognostic factor with increased liver-related mortality and treatment need. Due to the high prevalence of NAFLD, noninvasive risk stratification is needed to select patients for liver biopsy and treatment.

Objective

To compare the diagnostic accuracy of several widely available noninvasive tests for assessment of fibrosis among patients with NAFLD with or without nonalcoholic steatohepatitis (NASH).

Methods

We enrolled consecutive patients with NAFLD admitted to two Austrian referral centers who underwent liver biopsy. Liver stiffness measurement (LSM) was obtained by vibration-controlled transient elastography (VCTE, FibroScan) and blood samples were collected for determination of enhanced liver fibrosis (ELF) test, FibroMeter^V2G, FibroMeter^V3G, NAFLD fibrosis score (NFS), and fibrosis-4 index (FIB-4).

Results

Our study cohort contained 186 patients with histologically confirmed NAFLD. On liver histology, NASH was present in 92 patients (50%), significant fibrosis (F ≥ 2) in 71 patients (38%), advanced fibrosis (F ≥ 3) in 49 patients (26%), and F ≥ 3 plus NASH in 35 patients (19%). For diagnosis of F ≥ 2, F ≥ 3, and F ≥ 3 plus NASH, respectively, receiver operating characteristic (ROC) analysis revealed superior diagnostic accuracy of ELF score (area under ROC curve (AUROC) 0.85, 0.90, 0.90), FibroMeter^V2G (AUROC 0.86, 0.88, 0.89), FibroMeter^V3G (AUROC 0.84, 0.88, 0.88), and LSM per protocol (AUROC 0.87, 0.95, 0.91) versus FIB-4 (AUROC 0.80, 0.82, 0.81) or NFS (AUROC 0.78, 0.80, 0.79).

Conclusion

Proprietary fibrosis panels and VCTE show superior diagnostic accuracy for noninvasive diagnosis of fibrosis stage in NAFLD as compared to FIB-4 and NFS.

Screening for Nonalcoholic Fatty Liver Disease in the Primary Care Clinic

Nonalcoholic fatty liver disease (NAFLD) is a spectrum of diseases ranging from simple hepatic steatosis to nonalcoholic steatohepatitis (NASH) to advanced fibrosis and cirrhosis as well as liver cancer. Despite the significant morbidity associated with NAFLD, there are no global consensus guidelines to screen for liver fibrosis in patients considered high risk, including patients older than 50 years with type 2 diabetes or metabolic syndrome. Multiple therapies are currently being investigated and may soon receive regulatory approval for use in the clinic. It is suggested that patients at high risk for NAFLD be screened in the outpatient setting. This article aims to supply primary care providers (PCPs) with the knowledge and tools needed to properly evaluate a patient at high risk of developing significant liver disease from NASH. A tripartite algorithm is described to help PCPs identify patients with NAFLD using liver enzymes and abdominal ultrasound, assess the presence of advanced liver fibrosis using clinical prediction rules, and, if appropriate, determine when to refer patients to specialist care.

A critical appraisal of the use of ultrasound in hepatic steatosis

Introduction: Nonalcoholic fatty liver disease (NAFLD) spans steatosis through nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). NAFLD carries an increased risk of cardio-metabolic and liver-related events accounting for a substantial economic burden. Given that the natural history of NAFLD is critically dependent on the stage of fibrosis, non-invasively identifying the subgroup of patients at a higher risk of progressive disease is key. Areas covered: This review highlights the recent developments in the use of ultrasound-based techniques in NAFLD and their performance in predicting metabolic derangements, cardiovascular risk, and progression of liver disease, notably including diagnosis of fibrosing NASH, identification, and treatment of HCC. Expert opinion: Our ability to identify NAFLD patients and to estimate steatofibrosis with various ultrasound-based techniques has undergone tremendous progress over the last few years. However, it is more difficult to capture the inflammatory component of NASH with such ultrasound-assisted techniques. Moreover, semi-quantitative, quantitative, elastographic, and contrast-enhanced ultrasound techniques are increasingly being appreciated and made available but not all such techniques will gain success in the clinical and research area. Therefore, further research will precisely define the role of the most innovative ultrasonographic techniques, while reducing costs and increasing feasibility.

Position statement on the diagnosis and management of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a major national and international health burden. It is one of the most common liver diseases worldwide and the most common cause of abnormal liver enzymes in many developed countries. Non-alcoholic fatty liver disease is also known as an important cause of cryptogenic cirrhosis and second leading cause for liver transplantation. It is commonly associated with metabolic syndrome. Non-alcoholic steatohepatitis (NASH) is the progressive phenotype of NAFLD. In spite of promising performance of non-invasive tools, liver biopsy remains the gold standard test for NASH diagnosis. Over decades, many drugs have been investigated in phase 2 and 3; however, no approved therapy to date. Despite the alarming global rates of NAFLD, there are no local community-based studies on the prevalence of NAFLD or local practice guidelines on its management; this expert review aims to fill this gap.

Diagnosis and management of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in Western industrialised countries. The prevalence of NAFLD is increasing in parallel with the global rise in obesity and type 2 diabetes mellitus. NAFLD represents a spectrum of liver disease severity. NAFLD begins with accumulation of triacylglycerols in the liver (steatosis), and is defined by hepatic fatty infiltration amounting to greater than 5% by liver weight or the presence of over 5% of hepatocytes loaded with large fat vacuoles. In almost a quarter of affected individuals, steatosis progresses with the development of liver inflammation to non-alcoholic steatohepatitis (NASH). NASH is a potentially progressive liver condition and with ongoing liver injury and cell death can result in fibrosis. Progressive liver fibrosis may lead to the development of cirrhosis in a small proportion of patients. With the growing prevalence of NAFLD, there is an increasing need for a robust, accurate and non-invasive approach to diagnosing the different stages of this condition. This review will focus on (1) the biochemical tests and imaging techniques used to diagnose the different stages of NAFLD; and (2) a selection of the current management approaches focusing on lifestyle interventions and pharmacological therapies for NAFLD.

Accuracy of FibroScan Controlled Attenuation Parameter and Liver Stiffness Measurement in Assessing Steatosis and Fibrosis in Patients With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

We estimated the accuracy of FibroScan vibration-controlled transient elastography controlled attenuation parameter (CAP) and liver stiffness measurement (LSMs) in assessing steatosis and fibrosis in patients with suspected nonalcoholic liver disease (NAFLD).

METHODS

We collected data from 450 consecutive adults who underwent liver biopsy analysis for suspected NAFLD at 7 centers in the United Kingdom from March 2014 through January 2017. FibroScan examinations with M or XL probe were completed within the 2 weeks of the biopsy analysis (404 had a valid examination). The biopsies were scored by 2 blinded expert pathologists according to nonalcoholic steatohepatitis clinical research network criteria. Diagnostic accuracy was estimated using the area under the receiver operating characteristic curves (AUROCs) for the categories of steatosis and fibrosis. We assessed effects of disease prevalence on positive and negative predictive values. For LSM, the effects of histological parameters and probe type were appraised using multivariable analysis.

RESULTS

Using biopsy analysis as the reference standard, we found that CAP identified patients with steatosis with an AUROC of 0.87 (95% confidence interval [CI] 0.82-0.92) for S≥S1, 0.77 (95% CI 0.71-0.82) for S≥S2, and 0.70 (95% CI 0.64-0.75) for S=S3. Youden cutoff values for S≥S1, S≥S2, and S≥S3 were 302 dB/m, 331 dB/m, and 337 dB/m, respectively. LSM identified patients with fibrosis with AUROCs of 0.77 (95% CI 0.72-0.82) for F≥F2, 0.80 (95% CI 0.75-0.84) for F≥F3, and 0.89 (95% CI 0.84-0.93) for F=F4. Youden cutoff values for F≥F2, F≥F3, and F=F4 were 8.2 kPa, 9.7 kPa, and 13.6 kPa, respectively. Applying the optimal cutoff values, determined from this cohort, to populations of lower fibrosis prevalence increased negative predictive values and reduced positive predictive values. Multivariable analysis found that the only parameter that significantly affected LSMs was fibrosis stage (P<10^-16); we found no association with steatosis or probe type.

CONCLUSIONS

In a prospective analysis of patients with NAFLD, we found CAP and LSM by FibroScan to assess liver steatosis and fibrosis, respectively, with AUROC values ranging from 0.70 to 0.89. Probe type and steatosis did not affect LSM.

STUDY REGISTRATION

ClinicalTrials.gov Identifier: NCT01985009.

Nonalcoholic Fatty Liver Disease: Identification and Management of High-Risk Patients

Nonalcoholic fatty liver disease (NAFLD) is an increasingly dominant cause of liver disease worldwide. The progressive subtype, nonalcoholic steatohepatitis, is a leading indication for liver transplantation and a noteworthy cause of hepatocellular carcinoma. The overall prevalence of NAFLD is on the rise, and even more concerning data modeling predicts that an increasing percentage of those with NAFLD will develop advanced disease. This increased volume of patients with advanced liver disease will impose a significant health care burden in terms of resources and cost. Thus, the identification of patients with established fibrosis or at high risk of developing advanced liver disease is critical to effectively intervene and prevent overall and liver-related morbidity and mortality. Herein, we provide a framework to consider for the identification of patients with NAFLD at high risk of nonalcoholic steatohepatitis with advanced fibrosis and provide a critical assessment of currently accessible diagnostic and treatment modalities.

Noninvasive Assessment of Liver Disease in Patients With Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is estimated to afflict approximately 1 billion individuals worldwide. In a subset of NAFLD patients, who have the progressive form of NAFLD termed nonalcoholic steatohepatitis (NASH), it can progress to advanced fibrosis, cirrhosis, hepatocellular carcinoma, and liver-related morbidity and mortality. NASH is typically characterized by a specific pattern on liver histology, including steatosis, lobular inflammation, and ballooning with or without peri-sinusoidal fibrosis. Thus, key issues in NAFLD patients are the differentiation of NASH from simple steatosis and identification of advanced hepatic fibrosis. Until now, liver biopsy has been the gold standard for identifying these 2 critical end points, but has well-known limitations, including invasiveness; rare but potentially life-threatening complications; poor acceptability; sampling variability; and cost. Furthermore, due to the epidemic proportion of individuals with NAFLD worldwide, liver biopsy evaluation is impractical, and noninvasive assessment for the diagnosis of NASH and fibrosis is needed. Although much of the work remains to be done in establishing cost-effective strategies for screening for NASH, advanced fibrosis, and cirrhosis, in this review, we summarize the current state of the noninvasive assessment of liver disease in NAFLD, and we provide an expert synthesis of how these noninvasive tools could be utilized in clinical practice. Finally, we also list the key areas of research priorities in this area to move forward clinical practice.

A noninvasive indicator for the diagnosis of early hepatitis B virus-related liver fibrosis

BACKGROUND AND AIMS

Liver stiffness measurement (LSM) detected by FibroScan, combined with biochemical indexes, has shown potential values for assessment of liver fibrosis pathological degrees. Here we aimed to investigate a noninvasive method for hepatitis B virus-related liver fibrosis.

PATIENTS AND METHODS

In all, 307 patients who underwent liver biopsy and LSM measurement were included. Inflammation grades and fibrosis stages were evaluated according to METAVIR scoring system. Spearman's rank correlation analysis, logistic regression analysis, and receiver operating characteristic (ROC) curves analysis were performed to assess the factors' role in inflammation grades/fibrosis stages.

RESULTS

Spearman's rank correlation analysis showed that LSM, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and AST-to-platelet ratio index were positively correlated with inflammation grades and histologic fibrosis stages; platelets showed negative correlation, and AST-to-ALT ratio was not related. Logistic regression analysis indicated that LSM and APRI were risk factors for inflammation grades; LSM was the independent risk factor for fibrosis stages, P<0.0001, odds ratio>1. ROC curve analysis found LSM cutoff values and areas under the curve for the diagnosis of fibrosis scores: 6.95 and 0.804, respectively, for the diagnosis of significant fibrosis (F≥F2); 10.35 and 0.856, respectively, for severe fibrosis (F≥F3); 11.35 and 0.897, respectively, for cirrhosis (F=F4). Considering ALT as a confounding factor, ROC analysis was repeated in patients with normal and elevated ALT separately; the results indicated that when ALT was up to 40 U/l, LSM cutoff value and areas under the curve for the diagnosis of significant fibrosis (F≥F2) were 6.55 and 0.748, respectively.

CONCLUSION

This study provided a noninvasive treatment and prevention indicator for early hepatitis B virus-related liver fibrosis.

Nonalcoholic Fatty Liver Disease in Diabetes. Part I: Epidemiology and Diagnosis

Nonalcoholic fatty liver disease (NAFLD) and diabetes are common metabolic disorders whose prevalence rates are expected to rise worldwide, corresponding to aging and increasingly obese populations. Compared to the general population (around 25%), 50% to 70% of people with diabetes have NAFLD, and NAFLD severity (including fibrosis) tends to be worsened by the presence of diabetes. NAFLD is considered an emerging risk factor for type 2 diabetes mellitus and a contributor to the development of chronic diabetes-related complications. This reciprocal relationship demonstrates the importance of confirming suspected NAFLD in patients with diabetes. Due to the invasive nature of liver biopsy to assess NAFLD status, various alternative non-invasive modalities have been developed and validated. Here, we summarized the epidemiology of NAFLD in patients with diabetes and reviewed currently available imaging modalities and biomarker-based prediction models for their ability to detect liver steatosis and/or fibrosis.

The Mexican consensus on nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) affects nearly one third of the population worldwide. Mexico is one of the countries whose population has several risk factors for the disease and its prevalence could surpass 50%. If immediate action is not taken to counteract what is now considered a national health problem, the medium-term panorama will be very bleak. This serious situation prompted the Asociación Mexicana de Gastroenterología and the Asociación Mexicana de Hepatología to produce the Mexican Consensus on Fatty Liver Disease. It is an up-to-date and detailed review of the epidemiology, pathophysiology, clinical forms, diagnosis, and treatment of the disease, whose aim is to provide the Mexican physician with a useful tool for the prevention and management of nonalcoholic fatty liver disease.

Vibration-Controlled Transient Elastography to Assess Fibrosis and Steatosis in Patients With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

Vibration-controlled transient elastography (VCTE), which measures liver stiffness, has become an important tool for evaluating patients with nonalcoholic fatty liver disease (NAFLD). We aimed to determine the diagnostic accuracy of VCTE in detection of NAFLD in a multicenter cohort of patients.

METHODS

We performed a prospective study of 393 adults with NAFLD who underwent VCTE within 1 year of liver histology analysis (median time, 49 d; interquartile range, 25-78 d), from July 1, 2014, through July 31, 2017. Liver stiffness measurement (LSM) cut-off values for pairwise fibrosis stage and controlled attenuation parameter cut-off values for pairwise steatosis grade were determined using cross-validated area under the receiver operating characteristics curve (AUROC) analyses. Diagnostic statistics were computed at a sensitivity fixed at 90% and a specificity fixed at 90%.

RESULTS

LSM identified patients with advanced fibrosis with an AUROC of 0.83 (95% CI, 0.79- 0.87) and patients with cirrhosis with an AUROC of 0.93 (95% CI, 0.90-0.97). At a fixed sensitivity, a cut-off LSM of 6.5 kPa excluded advanced fibrosis with a negative predictive value of 0.91, and a cut-off LSM of 12.1 kPa excluded cirrhosis with a negative predictive value of 0.99. At a fixed specificity, LSM identified patients with advanced fibrosis with a positive predictive value of 0.71 and patients with cirrhosis with a positive predictive value of 0.41. Controlled attenuation parameter analysis detected steatosis with an AUROC of 0.76 (95% CI, 0.64-0.87). In contrast, the VCTE was less accurate in distinguishing lower fibrosis stages, higher steatosis grades, or the presence of NASH.

CONCLUSIONS

In a prospective study of adults with NAFLD, we found VCTE to accurately distinguish advanced vs earlier stages of fibrosis, using liver histology as the reference standard.

The Future of Nonalcoholic Fatty Liver Disease Treatment

Nonalcoholic Fatty Liver Disease (NAFLD) is the most common cause of chronic liver disease in the United States. The NAFLD subtype, nonalcoholic steatohepatitis, represents a progressive form of the disease that can lead to cirrhosis, portal hypertension, and hepatocellular carcinoma. NAFLD is a diagnosis of exclusion and is strongly related to obesity and the metabolic syndrome. Although there has been an explosion of exciting therapeutic avenues for NAFLD in recent years, the bedrock of management continues to be lifestyle modification, weight loss, and optimization of metabolic risk factors.

Repeating measurements by transient elastography in non-alcoholic fatty liver disease patients with high liver stiffness

BACKGROUND AND AIM

The Baveno VI Consensus recommends repeating examination in patients with high liver stiffness measurement (LSM) by transient elastography to reduce false-positive diagnosis of advanced liver disease. We tested whether repeating transient elastography can increase the overall diagnostic accuracy.

METHODS

Ninety-seven patients with non-alcoholic fatty liver disease who underwent two FibroScan examinations within 6 months prior to liver biopsy were evaluated. An LSM cut-off of 7.9 kPa was used to exclude F3-4 fibrosis.

RESULTS

Seventy-eight patients had high LSM at baseline, among whom 27 had low LSM on repeated testing; only four had F3 and none had cirrhosis. In contrast, 31 of 51 patients with high LSM at both examinations had F3-4. Nineteen patients had low LSM at baseline; none of them had F3-4 regardless of the second LSM results. If we took LSM <7.9 kPa at either examination as sufficient to exclude F3-4, the negative predictive value remained high at 91%. The positive predictive value for F3-4 increased from 45% in patients with high LSM at baseline to 61% in those with high LSM at both examinations. Sensitivity analysis using different cut-offs yielded similar results, with 76% of patients with LSM >12 kPa at both examinations having F3-4.

CONCLUSIONS

Transient elastography is a highly sensitive screening test to exclude F3-4 fibrosis in non-alcoholic fatty liver disease patients. One-third of patients with high LSM may have normal results on repeated examination. By repeating examination in cases with high LSM, one may spare patients from unnecessary liver biopsy.

Recommendations for the management of non-alcoholic fatty liver disease (NAFLD)

The Polish Group of Experts for Non-Alcoholic Fatty Liver Disease (PGE-NAFLD) is a multidisciplinary team of hepatology experts established by the Polish Association for the Study of Liver and the Polish Society of Epidemiology and Infectious Diseases. The recommendations for the management of non-alcoholic fatty liver disease have been developed by a group of experts in hepatology under the auspices of the Polish Association for the Study of Liver and the Polish Society of Epidemiology and Infectious Diseases. The recommendations are intended to help physicians understand the most current knowledge of NAFLD and apply it in clinical practice. Depending on the clinical situation, it may be necessary to individualize the management.

Current guidelines for the management of non-alcoholic fatty liver disease: A systematic review with comparative analysis

The current epidemic of non-alcoholic fatty liver disease (NAFLD) is reshaping the field of hepatology all around the world. The widespread diffusion of metabolic risk factors such as obesity, type2-diabetes mellitus, and dyslipidemia has led to a worldwide diffusion of NAFLD. In parallel to the increased availability of effective anti-viral agents, NAFLD is rapidly becoming the most common cause of chronic liver disease in Western Countries, and a similar trend is expected in Eastern Countries in the next years. This epidemic and its consequences have prompted experts from all over the word in identifying effective strategies for the diagnosis, management, and treatment of NAFLD. Different scientific societies from Europe, America, and Asia-Pacific regions have proposed guidelines based on the most recent evidence about NAFLD. These guidelines are consistent with the key elements in the management of NAFLD, but still, show significant difference about some critical points. We reviewed the current literature in English language to identify the most recent scientific guidelines about NAFLD with the aim to find and critically analyse the main differences. We distinguished guidelines from 5 different scientific societies whose reputation is worldwide recognised and who are representative of the clinical practice in different geographical regions. Differences were noted in: the definition of NAFLD, the opportunity of NAFLD screening in high-risk patients, the non-invasive test proposed for the diagnosis of NAFLD and the identification of NAFLD patients with advanced fibrosis, in the follow-up protocols and, finally, in the treatment strategy (especially in the proposed pharmacological management). These difference have been discussed in the light of the possible evolution of the scenario of NAFLD in the next years.

Diagnostic modalities for nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, and associated fibrosis

Nonalcoholic fatty liver disease (NAFLD) is a spectrum comprised of isolated steatosis, nonalcoholic steatohepatitis (NASH), advanced fibrosis, and cirrhosis. The majority of NAFLD subjects do not have NASH and do not carry a significant risk for liver-related adverse outcomes (cirrhosis and mortality). Globally, the prevalence of NAFLD is approximately 25%. In Asia, a gradient of high to low prevalence rates is noted from urban to rural areas. Given the prevalence of NAFLD, the clinical and economic burden of NAFLD and NASH can be substantial. With increasing recognition of NASH as an important liver disease, the diagnosis of NASH still requires a liver biopsy that is suboptimal. Although liver biopsy is the most accurate modality to diagnose and stage the severity of NASH, this method suffers from being invasive, costly, associated with potential complications, and plagued with interobserver variability of individual pathological features. A number of noninvasive modalities to diagnose NASH and stage liver fibrosis are being developed. These modalities include predictive models (NAFLD fibrosis score) and serum biomarkers such as enhanced liver fibrosis (ELF). Other tests are based on radiological techniques, such as transient elastography (TE) or magnetic resonance elastography (MRE), which are used to estimate liver stiffness as a potential surrogate of hepatic fibrosis. Although a dynamic field of research, most of these diagnostic modalities have area under the curve ranging between 0.76 and 0.90%, with MRE having the best predictive performance. In summary, developing safe and easily accessible noninvasive modalities to accurately diagnose and monitor NASH and associated fibrosis is of utmost importance in clinical practice and clinical research. These tests are not only important to risk stratify subjects at the greatest risk for progressive liver disease, but also to serve as appropriate surrogate endpoints for therapeutic clinical trials of NASH. (Hepatology 2018;68:349-360).

Diagnostic modalities for nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, and associated fibrosis

Nonalcoholic fatty liver disease (NAFLD) is a spectrum comprised of isolated steatosis, nonalcoholic steatohepatitis (NASH), advanced fibrosis, and cirrhosis. The majority of NAFLD subjects do not have NASH and do not carry a significant risk for liver-related adverse outcomes (cirrhosis and mortality). Globally, the prevalence of NAFLD is approximately 25%. In Asia, a gradient of high to low prevalence rates is noted from urban to rural areas. Given the prevalence of NAFLD, the clinical and economic burden of NAFLD and NASH can be substantial. With increasing recognition of NASH as an important liver disease, the diagnosis of NASH still requires a liver biopsy that is suboptimal. Although liver biopsy is the most accurate modality to diagnose and stage the severity of NASH, this method suffers from being invasive, costly, associated with potential complications, and plagued with interobserver variability of individual pathological features. A number of noninvasive modalities to diagnose NASH and stage liver fibrosis are being developed. These modalities include predictive models (NAFLD fibrosis score) and serum biomarkers such as enhanced liver fibrosis (ELF). Other tests are based on radiological techniques, such as transient elastography (TE) or magnetic resonance elastography (MRE), which are used to estimate liver stiffness as a potential surrogate of hepatic fibrosis. Although a dynamic field of research, most of these diagnostic modalities have area under the curve ranging between 0.76 and 0.90%, with MRE having the best predictive performance. In summary, developing safe and easily accessible noninvasive modalities to accurately diagnose and monitor NASH and associated fibrosis is of utmost importance in clinical practice and clinical research. These tests are not only important to risk stratify subjects at the greatest risk for progressive liver disease, but also to serve as appropriate surrogate endpoints for therapeutic clinical trials of NASH. (Hepatology 2018;68:349-360).

Hepatic Steatosis Assessment with Ultrasound Small-Window Entropy Imaging

Nonalcoholic fatty liver disease is a type of hepatic steatosis that is not only associated with critical metabolic risk factors but can also result in advanced liver diseases. Ultrasound parametric imaging, which is based on statistical models, assesses fatty liver changes, using quantitative visualization of hepatic-steatosis-caused variations in the statistical properties of backscattered signals. One constraint with using statistical models in ultrasound imaging is that ultrasound data must conform to the distribution employed. Small-window entropy imaging was recently proposed as a non-model-based parametric imaging technique with physical meanings of backscattered statistics. In this study, we explored the feasibility of using small-window entropy imaging in the assessment of fatty liver disease and evaluated its performance through comparisons with parametric imaging based on the Nakagami distribution model (currently the most frequently used statistical model). Liver donors (n = 53) and patients (n = 142) were recruited to evaluate hepatic fat fractions (HFFs), using magnetic resonance spectroscopy and to evaluate the stages of fatty liver disease (normal, mild, moderate and severe), using liver biopsy with histopathology. Livers were scanned using a 3-MHz ultrasound to construct B-mode, small-window entropy and Nakagami images to correlate with HFF analyses and fatty liver stages. The diagnostic values of the imaging methods were evaluated using receiver operating characteristic curves. The results demonstrated that the entropy value obtained using small-window entropy imaging correlated well with log10(HFF), with a correlation coefficient r = 0.74, which was higher than those obtained for the B-scan and Nakagami images. Moreover, small-window entropy imaging also resulted in the highest area under the receiver operating characteristic curve (0.80 for stages equal to or more severe than mild; 0.90 for equal to or more severe than moderate; 0.89 for severe), which indicated that non-model-based entropy imaging-using the small-window technique-performs more favorably than other techniques in fatty liver assessment.