The times they are a-changin' (for NAFLD as well)

Metabolic dysfunction-associated steatotic liver disease in adults

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the umbrella term that comprises metabolic dysfunction-associated steatotic liver, or isolated hepatic steatosis, through to metabolic dysfunction-associated steatohepatitis, the progressive necroinflammatory disease form that can progress to fibrosis, cirrhosis and hepatocellular carcinoma. MASLD is estimated to affect more than one-third of adults worldwide. MASLD is closely associated with insulin resistance, obesity, gut microbial dysbiosis and genetic risk factors. The obesity epidemic and the growing prevalence of type 2 diabetes mellitus greatly contribute to the increasing burden of MASLD. The treatment and prevention of major metabolic comorbidities such as type 2 diabetes mellitus and obesity will probably slow the growth of MASLD. In 2023, the field decided on a new nomenclature and agreed on a set of research and action priorities, and in 2024, the US FDA approved the first drug, resmetirom, for the treatment of non-cirrhotic metabolic dysfunction-associated steatohepatitis with moderate to advanced fibrosis. Reliable, validated biomarkers that can replace histology for patient selection and primary end points in MASH trials will greatly accelerate the drug development process. Additionally, noninvasive tests that can reliably determine treatment response or predict response to therapy are warranted. Sustained efforts are required to combat the burden of MASLD by tackling metabolic risk factors, improving risk stratification and linkage to care, and increasing access to therapeutic agents and non-pharmaceutical interventions.

Associations between multiple metabolic biomarkers with steatotic liver disease subcategories: A 5-year Chinese cohort study

The effectiveness of established biomarkers for non-alcoholic fatty liver disease (NAFLD) within the updated framework of steatotic liver disease (SLD) remains uncertain. This cohort study examines the association of four metabolic biomarkers-retinol-binding protein 4 (RBP-4), fibroblast growth factor 21 (FGF-21), adiponectin, and osteocalcin-with SLD and its subtypes: metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction with alcohol-related liver disease (MetALD)/alcohol-related liver disease (ALD). Among 3,504 Chinese participants aged 55-70, 938 (26.8%) have developed SLD over 5 years, including 871 with MASLD and 67 with MetALD/ALD. The findings indicate that models incorporating RBP-4, FGF-21, adiponectin, and osteocalcin improve predictive accuracy for SLD beyond conventional models. Notably, adiponectin emerges as the most versatile marker, while elevated baseline levels of FGF-21 or RBP-4 indicate specific needs for metabolic or alcohol-related interventions, respectively, supporting tailored precision medicine strategies.

Metabolic dysfunction-associated steatotic liver disease and MetALD increases the risk of liver cancer and gastrointestinal cancer: A nationwide cohort study

BACKGROUND

The new nomenclature of metabolic dysfunction-associated steatotic liver disease (MASLD) substituting nonalcoholic fatty liver disease was proposed along with a new category of MASLD with increased alcohol intake (MetALD).

AIMS

We aimed to explore the cancer risk by MASLD and MetALD.

METHODS

This nationwide cohort study included 3,596,709 participants who underwent a health check-up in 2011 in South Korea. Steatotic liver disease (SLD) was defined as a fatty liver index ≥30. Participants were categorized into four exclusive groups: MASLD, MetALD, other combination aetiology and no SLD. The subdistribution hazard ratio (SHR) was calculated using the Fine-Gray model after adjusting other variables.

RESULTS

During the 33.9 million person-years of follow-up, 285,845 participants (7.9%) developed cancers. Compared with no SLD, MASLD, MetALD and other combination aetiology had an increased risk of all cancer. Liver cancer risk escalated from no SLD to MASLD (SHR, 1.16; 95% CI, 1.12-1.21), MetALD (SHR, 2.06; 95% CI, 1.92-2.20) and other combination aetiology (SHR, 8.16; 95% CI, 7.69-8.67). Gastrointestinal cancers including oesophagus, stomach, colorectal, biliary and pancreas cancers increased in MASLD (SHR, 1.13; 95% CI, 1.11-1.15), MetALD (SHR, 1.17; 95% CI, 1.14-1.21) and other combination aetiology (SHR, 1.09; 95% CI, 1.05-1.13). A modest increase in lung cancer and hormone-sensitive cancer was observed with MASLD.

CONCLUSIONS

This study showed that MASLD and MetALD are associated with an increased risk of cancer, particularly liver and gastrointestinal cancers. The findings build new evidence for the clinical outcomes of MetALD while highlighting the importance of managing alcohol intake properly in MASLD and MetALD.

Prevalence, distribution, and hepatic fibrosis burden of the different subtypes of steatotic liver disease in primary care settings

BACKGROUND AND AIM

In relation to the new umbrella terminology for steatotic liver disease (SLD), we aimed to elucidate the prevalence, distribution, and clinical characteristics of the SLD subgroups in the primary care setting.

APPROACH AND RESULTS

We retrospectively collected data from 2535 individuals who underwent magnetic resonance elastography and MRI proton density fat fraction during health checkups in 5 primary care health promotion clinics. We evaluated the presence of cardiometabolic risk factors according to predefined criteria and divided all the participants according to the new SLD classification. The prevalence of SLD was 39.13% in the total cohort, and 95.77% of the SLD cases had metabolic dysfunction (one or more cardiometabolic risk factors). The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) was 29.51%, with those of metabolic dysfunction and alcohol associated steatotic liver disease (MetALD) and alcohol-associated liver disease (ALD) at 7.89% and 0.39%, respectively. According to the old criteria, the prevalence of NAFLD was 29.11%, and 95.80% of the NAFLD cases fulfilled the new criteria for MASLD. The distribution of SLD subtypes was highest for MASLD, at 75.40%, followed by MetALD at 20.06%, cryptogenic SLD at 3.33%, and ALD at 1.01%. The MetALD group had a significantly higher mean magnetic resonance elastography than the MASLD or ALD group.

CONCLUSION

Almost all the patients with NAFLD met the new criteria for MASLD. The fibrosis burden of the MetALD group was higher than those of the MASLD and ALD groups.

Metabolic dysfunction-associated steatotic liver disease: An opportunity for collaboration between cardiology and hepatology

Altered metabolic function has many detrimental effects on the body that can manifest as cardiovascular and liver diseases. Traditional approaches to understanding and treating metabolic dysfunction-associated disorders have been organ-centered, leading to silo-type disease care. However, given the broad impact that systemic metabolic dysfunction has on the human body, approaches that simultaneously involve multiple medical specialists need to be developed and encouraged to optimize patient outcomes. In this review, we highlight how several of the treatments developed for cardiac care may have a beneficial effect on the liver and vice versa, suggesting that there is a need to target the disease process, rather than specifically target the cardiovascular or liver specific sequelae of metabolic dysfunction.

Association of physical activity with MAFLD/MASLD and LF among adults in NHANES, 2017-2020

OBJECTIVES

To investigate the correlations between physical activity (PA) and metabolic associated fatty liver disease (MAFLD) or metabolic dysfunction-associated steatotic liver disease (MASLD) within a substantial population-based survey, and to examine the association between PA and liver fibrosis (LF).

METHODS

Data from the 2017-2020 NHANES cycle were utilized in this study. PA was divided into four types: leisure-time PA (LTPA), transportation-related PA (TPA), occupational PA (OPA) and total time PA (total PA, which is composed of OPA, TPA and LTPA). Weighted logistic regression models were performed to analyze the associations between PA and MAFLD/MASLD and LF. Mediation analysis was used to explore whether LTPA completely mediated the statistically significant relationship between total PA and MAFLD/MASLD or LF.

RESULTS

The study encompassed a sample size of 5897 participants aged 20 years and above, among the total participants, 2568 individuals with MAFLD and 2588 individuals with MASLD. There was no statistically significant correlation observed between OPA/TPA and MAFLD/MASLD and LF; however, active LTPA demonstrated an inverse association with MAFLD/MASLD (OR: 0.548; 95% CI: 0.458, 0.656/OR: 0.543; 95% CI: 0.453, 0.650), as well as a negative correlation with significant/advanced LF (OR: 0.457; 95% CI: 0.334,0.625/OR: 0.427; 95% CI: 0.295,0.619). There was also a significant inverse association between total PA and MAFLD/MASLD or LF, but this association was carried by the difference in LTPA.

CONCLUSION

Participation in active LTPA is associated with a reduced likelihood of MAFLD/MASLD and LF, while neither OPA nor TPA can replace these effects of LTPA.

Tailored Model of Care for Patients with Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as nonalcoholic fatty liver disease (NAFLD), is increasing globally, creating a growing public health concern. However, this disease is often not diagnosed, and accurate data on its epidemiology are limited in many geographical regions, making it challenging to provide proper care and implement effective national plans. To combat the increasing disease burden, screening and diagnosis must reach a significant number of high-risk subjects. Addressing MASLD as a health care challenge requires a multidisciplinary approach involving prevention, diagnosis, treatment, and care, with collaboration between multiple stakeholders in the health care system. This approach must be guided by national and global strategies, to be combined with efficient models of care developed through a bottom-up process. This review article highlights the pillars of the MASLD model of care (MoC), including screening, risk stratification, and establishing a clinical care pathway for management, in addition to discussing the impact of nomenclature change on the proposed MoC.

Implications of the new nomenclature of steatotic liver disease and definition of metabolic dysfunction-associated steatotic liver disease

BACKGROUND

The American and European liver associations have endorsed new nomenclature of steatotic liver disease (SLD) and definition of metabolic dysfunction-associated steatotic liver disease (MASLD).

AIMS

To review the historical development leading to the changes and to discuss the implications of the changes on research and clinical practice METHODS: We performed a literature search using keywords related to MASLD and non-alcoholic fatty liver disease (NAFLD).

RESULTS

The SLD umbrella allows classification of patients under the key categories of MASLD, alcohol-associated liver disease and a new entity termed MetALD, which represents MASLD with increased alcohol intake. The diagnosis of MASLD requires the demonstration of hepatic steatosis and at least one metabolic risk factor, whereas MASLD can co-exist with other liver diseases such as chronic viral hepatitis. Despite the change in definition, over 95% of patients previously known as having NAFLD fulfil diagnostic criteria for MASLD. It is conceivable that future clinical trials and biomarker studies will continue to exclude concomitant liver diseases. As most patients with MASLD are seen at primary care and non-hepatology settings, communication with other stakeholders is essential to ensure disease awareness and smooth adoption of the changes.

CONCLUSIONS

The new nomenclature is both a challenge, given the need for dissemination and education across the spectrum of stakeholders, and an opportunity to bring everyone together and spark new research to better understand epidemiology, natural history, diagnosis, biomarkers and management strategies across the spectrum of SLD.

A multisociety Delphi consensus statement on new fatty liver disease nomenclature

The principal limitations of the terms NAFLD and NASH are the reliance on exclusionary confounder terms and the use of potentially stigmatising language. This study set out to determine if content experts and patient advocates were in favor of a change in nomenclature and/or definition. A modified Delphi process was led by three large pan-national liver associations. The consensus was defined a priori as a supermajority (67%) vote. An independent committee of experts external to the nomenclature process made the final recommendation on the acronym and its diagnostic criteria. A total of 236 panelists from 56 countries participated in 4 online surveys and 2 hybrid meetings. Response rates across the 4 survey rounds were 87%, 83%, 83%, and 78%, respectively. Seventy-four percent of respondents felt that the current nomenclature was sufficiently flawed to consider a name change. The terms "nonalcoholic" and "fatty" were felt to be stigmatising by 61% and 66% of respondents, respectively. Steatotic liver disease was chosen as an overarching term to encompass the various aetiologies of steatosis. The term steatohepatitis was felt to be an important pathophysiological concept that should be retained. The name chosen to replace NAFLD was metabolic dysfunction-associated steatotic liver disease. There was consensus to change the definition to include the presence of at least 1 of 5 cardiometabolic risk factors. Those with no metabolic parameters and no known cause were deemed to have cryptogenic steatotic liver disease. A new category, outside pure metabolic dysfunction-associated steatotic liver disease, termed metabolic and alcohol related/associated liver disease (MetALD), was selected to describe those with metabolic dysfunction-associated steatotic liver disease, who consume greater amounts of alcohol per week (140-350 g/wk and 210-420 g/wk for females and males, respectively). The new nomenclature and diagnostic criteria are widely supported and nonstigmatising, and can improve awareness and patient identification.

A multisociety Delphi consensus statement on new fatty liver disease nomenclature

The principal limitations of the terms NAFLD and NASH are the reliance on exclusionary confounder terms and the use of potentially stigmatising language. This study set out to determine if content experts and patient advocates were in favour of a change in nomenclature and/or definition. A modified Delphi process was led by three large pan-national liver associations. The consensus was defined a priori as a supermajority (67%) vote. An independent committee of experts external to the nomenclature process made the final recommendation on the acronym and its diagnostic criteria. A total of 236 panellists from 56 countries participated in 4 online surveys and 2 hybrid meetings. Response rates across the 4 survey rounds were 87%, 83%, 83%, and 78%, respectively. Seventy-four percent of respondents felt that the current nomenclature was sufficiently flawed to consider a name change. The terms "nonalcoholic" and "fatty" were felt to be stigmatising by 61% and 66% of respondents, respectively. Steatotic liver disease was chosen as an overarching term to encompass the various aetiologies of steatosis. The term steatohepatitis was felt to be an important pathophysiological concept that should be retained. The name chosen to replace NAFLD was metabolic dysfunction-associated steatotic liver disease (MASLD). There was consensus to change the definition to include the presence of at least 1 of 5 cardiometabolic risk factors. Those with no metabolic parameters and no known cause were deemed to have cryptogenic steatotic liver disease. A new category, outside pure metabolic dysfunction-associated steatotic liver disease, termed metabolic and alcohol related/associated liver disease (MetALD), was selected to describe those with metabolic dysfunction-associated steatotic liver disease, who consume greater amounts of alcohol per week (140-350 g/wk and 210-420 g/wk for females and males, respectively). The new nomenclature and diagnostic criteria are widely supported and non-stigmatising, and can improve awareness and patient identification.

The intersection between alcohol-related liver disease and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) and alcohol-related liver disease (ALD) are the leading causes of chronic liver disease worldwide. NAFLD and ALD share pathophysiological, histological and genetic features and both alcohol and metabolic dysfunction coexist as aetiological factors in many patients with hepatic steatosis. A diagnosis of NAFLD requires the exclusion of significant alcohol consumption and other causes of liver disease. However, data suggest that significant alcohol consumption is often under-reported in patients classified as having NAFLD and that alcohol and metabolic factors interact to exacerbate the progression of liver disease. In this Review, we analyse existing data on the interaction between alcohol consumption and metabolic syndrome as well as the overlapping features and differences in the pathogenesis of ALD and NAFLD. We also discuss the clinical implications of the coexistence of alcohol consumption, of any degree, in patients with evidence of metabolic derangement as well as the use of alcohol biomarkers to detect alcohol intake. Finally, we summarize the evolving nomenclature of fatty liver disease and describe a recent proposal to classify patients at the intersection of NAFLD and ALD. We propose that, regardless of the presumed aetiology, patients with fatty liver disease should be evaluated for both metabolic syndrome and alcohol consumption to enable better prognostication and a personalized medicine approach.

A multisociety Delphi consensus statement on new fatty liver disease nomenclature

The principal limitations of the terms NAFLD and NASH are the reliance on exclusionary confounder terms and the use of potentially stigmatising language. This study set out to determine if content experts and patient advocates were in favor of a change in nomenclature and/or definition. A modified Delphi process was led by three large pan-national liver associations. The consensus was defined a priori as a supermajority (67%) vote. An independent committee of experts external to the nomenclature process made the final recommendation on the acronym and its diagnostic criteria. A total of 236 panelists from 56 countries participated in 4 online surveys and 2 hybrid meetings. Response rates across the 4 survey rounds were 87%, 83%, 83%, and 78%, respectively. Seventy-four percent of respondents felt that the current nomenclature was sufficiently flawed to consider a name change. The terms "nonalcoholic" and "fatty" were felt to be stigmatising by 61% and 66% of respondents, respectively. Steatotic liver disease was chosen as an overarching term to encompass the various aetiologies of steatosis. The term steatohepatitis was felt to be an important pathophysiological concept that should be retained. The name chosen to replace NAFLD was metabolic dysfunction-associated steatotic liver disease. There was consensus to change the definition to include the presence of at least 1 of 5 cardiometabolic risk factors. Those with no metabolic parameters and no known cause were deemed to have cryptogenic steatotic liver disease. A new category, outside pure metabolic dysfunction-associated steatotic liver disease, termed metabolic and alcohol related/associated liver disease (MetALD), was selected to describe those with metabolic dysfunction-associated steatotic liver disease, who consume greater amounts of alcohol per week (140-350 g/wk and 210-420 g/wk for females and males, respectively). The new nomenclature and diagnostic criteria are widely supported and nonstigmatising, and can improve awareness and patient identification.

Exploring the landscape of steatotic liver disease in the general US population

BACKGROUND AND OBJECTIVE

The aim of the present study is to explore the epidemiologic impact of the definition of steatotic liver disease (SLD) proposed by a multi-society (American Association for the Study of the Liver-the European Association for the Study of Liver Diseases-Asociación Latinoamericana para el Estudio del Hígado) Delphi consensus statement.

METHODS

This is a cross-sectional study of US adults participating in the 2017-2020 cycles of the National Health and Nutrition Examination Survey who were evaluated by vibration-controlled transient elastography. Hepatic steatosis and fibrosis were diagnosed by the median value of controlled attenuation parameter and liver stiffness measurement using cut-offs of 274 dB/m and 8.0 kPa, respectively. Recently proposed criteria for metabolic dysfunction-associated steatotic liver disease (MASLD), MetALD (MASLD + significant alcohol consumption), MASLD-Viral hepatitis and cryptogenic SLD were applied.

RESULTS

SLD was present in 42.1% (95% CI: 40.3-43.9) of the 3173 included participants. Among patients with SLD, 99.4% met the metabolic dysfunction definition. Moreover, 89.4%, 7.7%, 2.4%, 0.4% and 0.1% were defined as MASLD, MetALD, MASLD-Viral, alcoholic liver disease (ALD) (significant alcohol consumption without metabolic dysfunction) and cryptogenic, respectively. No patients without metabolic dysfunction had significant liver fibrosis, which was present in 15.2%, 9.5% and 19.5% of patients with MASLD, MetALD and MASLD-viral, respectively. Approximately, 90% of the overall adult US population could be diagnosed with metabolic dysfunction according to the consensus criteria. A high degree of concordance was found between MASLD and the previously proposed metabolic dysfunction-associated fatty liver disease definition.

CONCLUSIONS

Metabolic dysfunction is present in almost all patients with SLD in the United States. The new change in diagnostic criteria did not significantly impact disease prevalence.

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.

Current understanding and future perspectives on the impact of changing NAFLD to MAFLD on global epidemiology and clinical outcomes

INTRODUCTION

For the first time in nearly half a century, fatty liver disease has undergone a change in name and definition, from the exclusive term, non-alcoholic fatty liver disease (NAFLD), to the inclusion-based, metabolic-associated fatty liver disease (MAFLD). This has led investigators across the globe to evaluate the impact the nomenclature change has had on the epidemiology and natural history of the disease.

METHODS

This systematic review provides a comprehensive overview on how the shift in name and diagnostic criteria has influenced point prevalence in different geographic regions, as well as morbidity and mortality risk, whilst highlighting gaps in the literature that need to be addressed.

CONCLUSIONS

MAFLD prevalence is higher than NAFLD prevalence, carries a higher risk of overall mortality, with greater granularity in risk-stratification amongst MAFLD subtypes.

Critical appraisal of metabolic dysfunction-associated steatotic liver disease: Implication of Janus-faced modernity

The existing term non-alcoholic fatty liver disease (NAFLD) has raised substantial concerns due to its inherent disadvantages of using exclusionary diagnostic criteria and the stigmatizing word 'fatty.' Three pan-national liver associations set out to explore a new nomenclature to replace both NAFLD and its suggested alternative, metabolic (dysfunction)-associated fatty liver disease (MAFLD). They surveyed if a change in nomenclature and/or definition is favored and which nomenclature best communicates disease characteristics and increases awareness. In lieu of NAFLD/MAFLD, metabolic dysfunction-associated steatotic liver disease (MASLD) has been chosen, and an umbrella term, steatotic liver disease (SLD), encompassing the whole spectrum of liver disease, has been proposed. It has been suggested that cardiometabolic risk factors should be considered when categorizing SLD patients. Furthermore, a new subcategory, MASLD with increased alcohol intake (MetALD), casts light on a neglected group of patients with moderate or more alcohol consumption. The importance of metabolic dysfunction was acknowledged in this new nomenclature, but the precise contribution of metabolic dysfunction and alcohol consumption to the development and progression of SLD remains unclear. Herein, we review hepatologists' and endocrinologists' perspectives on the new nomenclature, along with its possible impact on clinical practice. Although it is premature to predict the settlement of the new nomenclature, this review may help build more evidence for a soft landing of it in the future.

Effect of spironolactone on pharmacological treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) was recently renamed to metabolic (dysfunction)-associated fatty liver disease (MAFLD) to better characterize its pathogenic origin. NAFLD represents, at least in western societies, a potential epidemic with raising prevalence. Its multifactorial pathogenesis is partially unraveled and till now there is no approved pharmacotherapy for NAFLD. A plethora of various choices are investigated in clinical trials, targeting an arsenal of different pathways and molecules. Since the mineralocorticoid receptor (MR) and renin-angiotensin-aldosterone system (RAAS) appear to be implicated in NAFLD, within this concise review, we focus on a rather classical and inexpensive pharmacological agent, spironolactone. We present the current lines of evidence of MR and RAAS-related preclinical models and human trials reporting an association with NAFLD. In conclusion, evidence about spironolactone of RAAS is commented, as potential future pharmacological management of NAFLD.

Comparison of Outcomes Between Metabolic Dysfunction-Associated Fatty Liver Disease and Non-alcoholic Fatty Liver Disease: A Meta-Analysis

Non-alcoholic fatty liver disease (NAFLD) encompasses a range of conditions, from fatty liver to cirrhosis. In response to evolving research and to better reflect the complex metabolic underpinnings, the term metabolic dysfunction-associated fatty liver disease (MAFLD) has been proposed. The aim of this meta-analysis was to compare cardiovascular events and all-cause mortality between NAFLD and MAFLD patients. The present study was conducted following the Preferred Reporting of Systematic Review and Meta-analysis (PRISMA) guidelines. We systematically searched PubMed, EMBASE, and the Web of Science to identify studies that compared cardiovascular outcomes in MAFLD and NAFLD from inception to July 31, 2023. Outcomes assessed in this meta-analysis included all-cause mortality, cardiovascular mortality, and cardiovascular events. A total of 11 studies were included in this meta-analysis. The risk of cardiovascular mortality was significantly higher in patients with MAFLD patients compared to NAFLD patients (risk ratio (RR): 1.48, 95% confidence interval (CI): 1.11 to 1.98). The risk of all-cause mortality was higher in MAFLD patients compared to NAFLD, and the difference was statistically significant (RR: 2.80, 95% CI: 2.39 to 3.28). The risk of cardiovascular events was significantly higher in MAFLD patients compared to NAFLD (RR: 1.18, 95% CI: 0.86 to 1.61). The key findings underscore that individuals diagnosed with MAFLD face a notably higher risk of all-cause mortality, cardiovascular mortality, and cardiovascular events when compared to those with NAFLD.

Problems and Challenges Associated with Renaming Non-alcoholic Fatty Liver Disease to Metabolic Associated Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) has become the world’s largest chronic liver disease in the 21st century, affecting 20%–30% of the world’s population. As the epidemiology, etiology, and pathogenesis of NAFLD have been studied in-depth, it has been gradually recognized that most patients with NAFLD have one or more combined metabolic abnormalities known as metabolic syndrome. In 2020, the international expert group changed the name of NAFLD to metabolic-associated fatty liver disease (MAFLD) and proposed new diagnostic criteria for MAFLD and MAFLD-related liver cirrhosis, as well as the conceptual framework of other cause-related fatty liver diseases to avoid diagnosis based on the exclusion of other causes and better reflect its pathogenesis. However, there are still many ambiguities in the term, and changing the name does not address the unmet key needs in the field. The change from NAFLD to MAFLD was not just a change of definition. The problems and challenges are summarized as follows: epidemiology, children, rationality of “metabolism,” diagnostic criteria, double/multiple causes, drug discovery, clinical trials, and awareness raising. Metabolic-associated fatty liver disease has complex disease characteristics, and there are still some problems that need to be solved.

Comparison between metabolic-associated fatty liver disease and nonalcoholic fatty liver disease: From nomenclature to clinical outcomes

As a result of the obesity epidemic, Nonalcoholic fatty liver disease (NAFLD) and its complications have increased among millions of people. Consequently, a group of experts recommended changing the term NAFLD to an inclusive terminology more reflective of the underlying pathogenesis; metabolic-associated fatty liver disease (MAFLD). This new term of MAFLD has its own disease epidemiology and clinical outcomes prompting efforts in studying its differences from NAFLD. This article discusses the rationale behind the nomenclature change, the main differences, and its clinical implications.

Peroxisome Proliferator-Activated Receptor-γ as a Target and Regulator of Epigenetic Mechanisms in Nonalcoholic Fatty Liver Disease

Peroxisome proliferator-activated receptor-γ (PPARγ) belongs to the superfamily of nuclear receptors that control the transcription of multiple genes. Although it is found in many cells and tissues, PPARγ is mostly expressed in the liver and adipose tissue. Preclinical and clinical studies show that PPARγ targets several genes implicated in various forms of chronic liver disease, including nonalcoholic fatty liver disease (NAFLD). Clinical trials are currently underway to investigate the beneficial effects of PPARγ agonists on NAFLD/nonalcoholic steatohepatitis. Understanding PPARγ regulators may therefore aid in unraveling the mechanisms governing the development and progression of NAFLD. Recent advances in high-throughput biology and genome sequencing have greatly facilitated the identification of epigenetic modifiers, including DNA methylation, histone modifiers, and non-coding RNAs as key factors that regulate PPARγ in NAFLD. In contrast, little is still known about the particular molecular mechanisms underlying the intricate relationships between these events. The paper that follows outlines our current understanding of the crosstalk between PPARγ and epigenetic regulators in NAFLD. Advances in this field are likely to aid in the development of early noninvasive diagnostics and future NAFLD treatment strategies based on PPARγ epigenetic circuit modification.

NAFLD VS MAFLD. The evidence-based debate has come. Time to change?

Non-alcoholic fatty liver disease (NAFLD) affects one-third of the world's adult population and is linked to metabolic syndrome. It can progress to steatohepatitis, cirrhosis and hepatocellular carcinoma. During the last four decades, it has been the subject of exhaustive research in multiple aspects to define its epidemiology, pathophysiological mechanisms and therapy. In 2020, a group of international experts proposed the change of name to metabolic-associated fatty liver disease (MAFLD) with the main objective of making it an inclusive diagnosis prioritizing metabolic abnormalities. However, the change in terminology included the modification of the diagnostic criteria allowing the non-exclusion of other concomitant liver diseases such as alcohol liver disease, and chronic hepatitis B or C. The proposal precipitated a wave of debates among experts based on theoretical opinions on the desirability of the rapid adoption of the new terminology. But it also precipitated a wave of epidemiological and clinical studies which, two years later, have provided clinical evidence on the differences and similarities of the two entities, specially, those that could be considered for future refinements of the diagnostic criteria of MAFLD. Likewise, this evidence may contribute to deciding the time of adoption of this terminology. In this text, we discuss, in general terms, important aspects of the clinical evidence that has been generated to date in cross-sectional and longitudinal studies focusing on clinical characteristics and outcomes, mainly on all-cause and specific mortality of MAFLD.

Are there outcome differences between NAFLD and metabolic-associated fatty liver disease?

BACKGROUND

Given the association of NAFLD with metabolic risks, a name change to MAFLD is proposed. We compared the long-term outcomes of NAFLD and MAFLD.

METHODS

We included patients with fatty liver disease (FLD) from NHANES III and NHANES 2017-2018 (FLD defined as moderate to severe hepatic steatosis by ultrasound for NHANES III and as having a controlled attenuation parameter ≥285 dB/m for NHANES 2017-2018). NAFLD was defined as FLD without other liver diseases and excess alcohol use. Metabolic-associated fatty liver disease (MAFLD) was defined as FLD and metabolic dysfunction per criteria. All NHANES III participants had linked mortality data through December 31, 2015.

RESULTS

NHANES III participants (n = 12,878): mean age 43.1 years old; 49.5% male; 20.3% with FLD, 16.5% with NAFLD, and 18.1% with MAFLD. NHANES 2017-2018 participants (n = 4328): mean age 48.0 years old; 49.1% male; 36.8% with FLD, 34.2% with NAFLD, and 36.3% with MAFLD. Excellent concordance was noted between MAFLD and NAFLD diagnosis in both data sets (kappa coefficient = 0.83-0.94). Except for components of each definition (e.g., alcohol use for MAFLD), no other major differences in clinical characteristics were noted. During up to 27 years of follow-up (median of 22.8 years), no differences in cumulative all-cause and cause-specific mortality were noted. In addition to the stage of fibrosis, insulin resistance was a predictor of liver mortality in NAFLD, and alcohol-associated liver disease (ALD) was a predictor of mortality in MAFLD.

CONCLUSIONS

MAFLD and NAFLD have similar clinical profiles and long-term outcomes. The increased liver-related mortality among NAFLD is driven by insulin resistance, and among MAFLD is primarily driven by ALD.

Biomarkers of Metabolic (Dysfunction)-associated Fatty Liver Disease: An Update

The prevalence of metabolic (dysfunction)-associated fatty liver disease (MAFLD) is rapidly increasing and affects up to two billion individuals globally, and this has also resulted in increased risks for cirrhosis, hepatocellular carcinoma, and liver transplants. In addition, it has also been linked to extrahepatic consequences, such as cardiovascular disease, diabetes, and various types of cancers. However, only a small proportion of patients with MAFLD develop these complications. Therefore, the identification of high-risk patients is paramount. Liver fibrosis is the major determinant in developing these complications. Although, liver biopsy is still considered the gold standard for the assessment of patients with MAFLD. Because of its invasive nature, among many other limitations, the search for noninvasive biomarkers for MAFLD remains an area of intensive research. In this review, we provide an update on the current and future biomarkers of MAFLD, including a discussion of the associated genetics, epigenetics, microbiota, and metabolomics. We also touch on the next wave of multiomic-based biomarkers.

Advancing the global public health agenda for NAFLD: a consensus statement

Non-alcoholic fatty liver disease (NAFLD) is a potentially serious liver disease that affects approximately one-quarter of the global adult population, causing a substantial burden of ill health with wide-ranging social and economic implications. It is a multisystem disease and is considered the hepatic component of metabolic syndrome. Unlike other highly prevalent conditions, NAFLD has received little attention from the global public health community. Health system and public health responses to NAFLD have been weak and fragmented, and, despite its pervasiveness, NAFLD is largely unknown outside hepatology and gastroenterology. There is only a nascent global public health movement addressing NAFLD, and the disease is absent from nearly all national and international strategies and policies for non-communicable diseases, including obesity. In this global Delphi study, a multidisciplinary group of experts developed consensus statements and recommendations, which a larger group of collaborators reviewed over three rounds until consensus was achieved. The resulting consensus statements and recommendations address a broad range of topics - from epidemiology, awareness, care and treatment to public health policies and leadership - that have general relevance for policy-makers, health-care practitioners, civil society groups, research institutions and affected populations. These recommendations should provide a strong foundation for a comprehensive public health response to NAFLD.

Epidemiology and Clinical Outcomes of Metabolic (Dysfunction)-associated Fatty Liver Disease

Metabolic (dysfunction)-associated fatty liver disease (MAFLD) is currently the most common chronic liver disease and affects at least a quarter of the global adult population. It has rapidly become one of the leading causes of hepatocellular carcinoma and cirrhosis in Western countries. In this review, we discuss the nomenclature and definition of MAFLD as well as its prevalence and incidence in different geographical regions. Although cardiovascular disease remains the leading cause of death in MAFLD patients, the proportion of patients dying from hepatic complications increases sharply as the disease progresses to advanced liver fibrosis and cirrhosis. In addition, patients with MAFLD are at increased risk of various extrahepatic cancers. Although a causal relationship between MAFLD and extrahepatic cancers has not been established, clinicians should recognize the association and consider cancer screening (e.g., for colorectal cancer) as appropriate.

Non-alcoholic fatty liver disease: a multidisciplinary clinical practice approach—the institutional adaptation to existing Clinical Practice Guidelines

Abstract

Non-alcoholic fatty liver disease (NAFLD) is among the most frequently encountered chronic liver diseases in everyday clinical practice. It is considered the hepatic manifestation of metabolic syndrome. Today, liver biopsy is still the gold standard for NAFLD confirmation and assessing NAFLD's possible progression to non-alcoholic steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Because of the high prevalence of NAFLD and potential associated risks of invasive diagnostic procedures, it is of great interest to recruit the patients for liver biopsy. However, as the presence of liver fibrosis determines the further clinical course, liver biopsy is expectedly reserved for those with increased fibrosis risk. The quality of liver biopsy recruitment and patient monitoring could be significantly improved by using non-invasive tools to assess liver fibrosis presence and interactive collaboration between general practitioners, gastroenterologists, and endocrinologists. As a result, the quality of liver biopsy recruitment and patients monitoring could be significantly improved. Here, we proposed clinical practice guidelines that could be implemented for everyday clinical practice in NAFLD patients.

Hepatopathy Associated With Type 1 Diabetes: Distinguishing Non-alcoholic Fatty Liver Disease From Glycogenic Hepatopathy

Autoimmune destruction of pancreatic β-cells results in the permanent loss of insulin production in type 1 diabetes (T1D). The daily necessity to inject exogenous insulin to treat hyperglycemia leads to a relative portal vein insulin deficiency and potentiates hypoglycemia which can induce weight gain, while daily fluctuations of blood sugar levels affect the hepatic glycogen storage and overall metabolic control. These, among others, fundamental characteristics of T1D are associated with the development of two distinct, but in part clinically similar hepatopathies, namely non-alcoholic fatty liver disease (NAFLD) and glycogen hepatopathy (GlyH). Recent studies suggest that NAFLD may be increasingly common in T1D because more people with T1D present with overweight and/or obesity, linked to the metabolic syndrome. GlyH is a rare but underdiagnosed complication hallmarked by extremely brittle metabolic control in, often young, individuals with T1D. Both hepatopathies share clinical similarities, troubling both diagnosis and differentiation. Since NAFLD is increasingly associated with cardiovascular and chronic kidney disease, whereas GlyH is considered self-limiting, awareness and differentiation between both condition is important in clinical care. The exact pathogenesis of both hepatopathies remains obscure, hence licensed pharmaceutical therapy is lacking and general awareness amongst physicians is low. This article aims to review the factors potentially contributing to fatty liver disease or glycogen storage disruption in T1D. It ends with a proposal for clinicians to approach patients with T1D and potential hepatopathy.

Insights into Nonalcoholic Fatty-Liver Disease Heterogeneity

The acronym nonalcoholic fatty-liver disease (NAFLD) groups a heterogeneous patient population. Although in many patients the primary driver is metabolic dysfunction, a complex and dynamic interaction of different factors (i.e., sex, presence of one or more genetic variants, coexistence of different comorbidities, diverse microbiota composition, and various degrees of alcohol consumption among others) takes place to determine disease subphenotypes with distinct natural history and prognosis and, eventually, different response to therapy. This review aims to address this topic through the analysis of existing data on the differential contribution of known factors to the pathogenesis and clinical expression of NAFLD, thus determining the different clinical subphenotypes observed in practice. To improve our understanding of NAFLD heterogeneity and the dominant drivers of disease in patient subgroups would predictably impact on the development of more precision-targeted therapies for NAFLD.

Non-alcoholic fatty liver disease: A patient guideline

This patient guideline is intended for all patients at risk of or living with non-alcoholic fatty liver disease (NAFLD). NAFLD is the most frequent chronic liver disease worldwide and comes with a high disease burden. Yet, there is a lot of unawareness. Furthermore, many aspects of the disease are still to be unravelled, which has an important impact on the information that is given (or not) to patients. Its management requires a close interaction between patients and their many healthcare providers. It is important for patients to develop a full understanding of NAFLD in order to enable them to take an active role in their disease management. This guide summarises the current knowledge relevant to NAFLD and its management. It has been developed by patients, patient representatives, clinicians and scientists and is based on current scientific recommendations, intended to support patients in making informed decisions.

Defining paediatric metabolic (dysfunction)-associated fatty liver disease: an international expert consensus statement

The term non-alcoholic fatty liver disease (NAFLD), and its definition, have limitations for both adults and children. The definition is most problematic for children, for whom alcohol consumption is usually not a concern. This problematic definition has prompted a consensus to rename and redefine adult NAFLD associated with metabolic dysregulation to metabolic (dysfunction)-associated fatty liver disease (MAFLD). Similarities, distinctions, and differences exist in the causes, natural history, and prognosis of fatty liver diseases in children compared with adults. In this Viewpoint we, an international panel, propose an overarching framework for paediatric fatty liver diseases and an age-appropriate MAFLD definition based on sex and age percentiles. The framework recognises the possibility of other coexisting systemic fatty liver diseases in children. The new MAFLD diagnostic criteria provide paediatricians with a conceptual scaffold for disease diagnosis, risk stratification, and improved clinical and multidisciplinary care, and they align with a definition that is valid across the lifespan.

Risk stratification using sarcopenia status among subjects with metabolic dysfunction-associated fatty liver disease

BACKGROUND

Sarcopenia is a significant indicator of the severity of non-alcoholic fatty liver disease. We investigated whether sarcopenia could identify subgroups with different risk of liver fibrosis and atherosclerotic cardiovascular disease (ASCVD) among subjects with metabolic dysfunction-associated fatty liver disease (MAFLD).

METHODS

Subjects from the Korea National Health and Nutrition Examination Survey 2008-2011 were selected (n = 8361). Sarcopenia was defined using the sarcopenia index. Hepatic steatosis was defined as a fatty liver index ≥30. Significant liver fibrosis was defined as a fibrosis-4 index (FIB-4) ≥2.67 or the highest quartile of non-alcoholic fatty liver disease fibrosis score (NFS). High probability of ASCVD was defined as ASCVD risk score >10%.

RESULTS

The mean age was 48.5 ± 15.6 years, and 42.6% of subjects were male. The prevalence of MAFLD was 37.3% (n = 3116 of 8361), and the proportion of sarcopenic subjects was 9.9% among those with MAFLD. After adjusting for confounders, the risk of significant liver fibrosis significantly increased from non-sarcopenic subjects with MAFLD [odds ratio (OR) = 1.57 by FIB-4 and 2.13 by NFS] to sarcopenic subjects with MAFLD (OR = 4.51 by FIB-4 and 5.72 by NFS), compared with subjects without MAFLD (all P < 0.001). The risk for high probability of ASCVD significantly increased from non-sarcopenic subjects with MAFLD (OR = 1.47) to sarcopenic subjects with MAFLD (OR = 4.08), compared with subjects without MAFLD (all P < 0.001).

CONCLUSIONS

The risks of significant liver fibrosis and ASCVD differed significantly according to sarcopenic status among subjects with MAFLD. An assessment of sarcopenia might be helpful in risk stratification among subjects with MAFLD.

Cardiovascular and renal burdens of metabolic associated fatty liver disease from serial US national surveys, 1999-2016

Background:

Non-communicable chronic diseases have become the leading causes of disease burden worldwide. The trends and burden of “metabolic associated fatty liver disease” (MAFLD) are unknown. We aimed to investigate the cardiovascular and renal burdens in adults with MAFLD and non-alcoholic fatty liver disease (NAFLD).

Methods:

Nationally representative data were analyzed including data from 19,617 non-pregnant adults aged ≥20 years from the cross-sectional US National Health and Nutrition Examination Survey periods, 1999 to 2002, 2003 to 2006, 2007 to 2010, and 2011 to 2016. MAFLD was defined by the presence of hepatic steatosis plus general overweight/obesity, type 2 diabetes mellitus, or evidence of metabolic dysregulation.

Results:

The prevalence of MAFLD increased from 28.4% (95% confidence interval 26.3–30.6) in 1999 to 2002 to 35.8% (33.8–37.9) in 2011 to 2016. In 2011 to 2016, among adults with MAFLD, 49.0% (45.8–52.2) had hypertension, 57.8% (55.2–60.4) had dyslipidemia, 26.4% (23.9–28.9) had diabetes mellitus, 88.7% (87.0–80.1) had central obesity, and 18.5% (16.3–20.8) were current smokers. The 10-year cardiovascular risk ranged from 10.5% to 13.1%; 19.7% (17.6–21.9) had chronic kidney diseases (CKDs). Through the four periods, adults with MAFLD showed an increase in obesity; increase in treatment to lower blood pressure (BP), lipids, and hemoglobin A1c; and increase in goal achievements for BP and lipids but not in goal achievement for glycemic control in diabetes mellitus. Patients showed a decreasing 10-year cardiovascular risk over time but no change in the prevalence of CKDs, myocardial infarction, or stroke. Generally, although participants with NAFLD and those with MAFLD had a comparable prevalence of cardiovascular disease and CKD, the prevalence of MAFLD was significantly higher than that of NAFLD.

Conclusions:

From 1999 to 2016, cardiovascular and renal risks and diseases have become highly prevalent in adults with MAFLD. The absolute cardiorenal burden may be greater for MAFLD than for NAFLD. These data call for early identification and risk stratification of MAFLD and close collaboration between endocrinologists and hepatologists.

Perspectives on Precision Medicine Approaches to NAFLD Diagnosis and Management

Precision medicine defines the attempt to identify the most effective approaches for specific subsets of patients based on their genetic background, clinical features, and environmental factors. Nonalcoholic fatty liver disease (NAFLD) encompasses the alcohol-like spectrum of liver disorders (steatosis, steatohepatitis with/without fibrosis, and cirrhosis and hepatocellular carcinoma) in the nonalcoholic patient. Recently, disease renaming to MAFLD [metabolic (dysfunction)-associated fatty liver disease] and positive criteria for diagnosis have been proposed. This review article is specifically devoted to envisaging some clues that may be useful to implementing a precision medicine-oriented approach in research and clinical practice. To this end, we focus on how sex and reproductive status, genetics, intestinal microbiota diversity, endocrine and metabolic status, as well as physical activity may interact in determining NAFLD/MAFLD heterogeneity. All these factors should be considered in the individual patient with the aim of implementing an individualized therapeutic plan. The impact of considering NAFLD heterogeneity on the development of targeted therapies for NAFLD subgroups is also extensively discussed.

External Validation of Surrogate Indices of Fatty Liver in the General Population: the Bagnacavallo Study

We externally validated the fatty liver index (FLI), the lipid accumulation product (LAP), the hepatic steatosis index (HSI), and the Zhejiang University index (ZJU) for the diagnosis of fatty liver (FL) and non-alcoholic fatty liver disease (NAFLD) in the general population. The validation was performed on 2159 citizens of the town of Bagnacavallo (Ravenna, Italy). Calibration was evaluated by calculating the calibration slope and intercept and by inspecting calibration plots; discrimination was evaluated using the c-statistic. The average calibration slope was 1 and the average intercept was 0 for all combinations of outcomes and indices. For the diagnosis of FL, the c-statistic was 0.85 for FLI, 0.83 for ZJU, 0.82 for HSI, and 0.80 for LAP; for the diagnosis of NAFLD, the c-statistic was 0.77 for FLI, 0.76 for ZJU, 0.75 for HSI, and 0.74 for LAP. All indices were strongly correlated with each other. In conclusion, FLI, LAP, HSI, and ZJU perform similarly well to diagnose FL and NAFLD in the Bagnacavallo population, even if FLI has a small advantage as discrimination is concerned.