MetALD: new opportunities to understand the role of alcohol in steatotic liver disease

Envisioning how to advance the MASH field

Since 1980, the cumulative effort of scientists and health-care stakeholders has advanced the prerequisites to address metabolic dysfunction-associated steatotic liver disease (MASLD), a prevalent chronic non-communicable liver disease. This effort has led to, among others, the approval of the first drug specific for metabolic dysfunction-associated steatohepatitis (MASH; formerly known as nonalcoholic steatohepatitis). Despite substantial progress, MASLD is still a leading cause of advanced chronic liver disease, including primary liver cancer. This Perspective contextualizes the nomenclature change from nonalcoholic fatty liver disease to MASLD and proposes important considerations to accelerate further progress in the field, optimize patient-centric multidisciplinary care pathways, advance pharmacological, behavioural and diagnostic research, and address health disparities. Key regulatory and other steps necessary to optimize the approval and access to upcoming additional pharmacological therapeutic agents for MASH are also outlined. We conclude by calling for increased education and awareness, enhanced health system preparedness, and concerted action by policy-makers to further the public health and policy agenda to achieve at least parity with other non-communicable diseases and to aid in growing the community of practice to reduce the human and economic burden and end the public health threat of MASLD and MASH by 2030.

Progress is impossible without change: understanding the evolving nomenclature of steatotic liver disease and its effect on hepatology practice

The American, European, and Latin American liver societies have proposed a change in the nomenclature we use to describe alcohol-related liver disease and non-alcoholic fatty liver disease. Additionally, a term encompassing both is now advocated: steatotic liver disease, which includes metabolic dysfunction associated steatotic liver disease (MASLD) and MASLD with greater alcohol consumption (MetALD). These classifications offer increased relevance for clinicians, researchers, and patients alike. In this Viewpoint, we discuss the basis for this nomenclature shift and how it was developed. We also explore the challenges that will be faced in the adoption of such change. The proposed change seeks to banish stigma associated with phrasing such as alcoholic and fatty. However stigma, particularly related to the term fatty, is culturally nuanced, and reflects different entities depending on location. If such a change is internationally accepted, there will be wide-reaching effects on practitioners in primary care and metabolic medicine, and on patients. We discuss those effects and the opportunities the nomenclature change could offer, particularly for patients with alcohol and metabolic risk factors who represent a group previously ignored by clinical trials.

Prevalence of Steatotic Liver Disease (MASLD, MetALD, and ALD) in the United States: NHANES 2017-2020

Following the Delphi consensus process, the term steatotic liver disease (SLD) was introduced to replace fatty liver disease, while the term metabolic dysfunction-associated steatotic liver disease (MASLD) emerged as the successor to the term nonalcoholic fatty liver disease (NAFLD).1 This revised nomenclature aims to enhance precision and mitigate negative connotations and potential stigmatization, while refining comprehension and disease categorization. Concurrently, a novel category was introduced to capture individuals whose alcohol consumption exceeded the previously defined thresholds of NAFLD but remained unclassified within the existing system. This category, termed MetALD, now delineates a spectrum of conditions and is defined as a daily intake of 20 to 50 g of alcohol (or weekly 140-350 g) for females and 30 to 60 g daily for males (or weekly 210-420 g).1 Within the MetALD spectrum, some individuals might predominantly exhibit MASLD characteristics, whereas others might be more inclined toward alcoholic liver disease (ALD).1 In the present study, we used a US nationally representative data set to calculate the prevalence of SLD and its subcategories in the United States.

Healthcare interactions prior to first hospital admission with alcohol-related liver disease

BACKGROUND AND AIMS

To examine the healthcare contacts of patients in the year before an index admission to hospital with alcohol-related liver disease (ArLD) to identify where opportunities for earlier identification of alcohol use disorders (AUD) and ArLD and intervention may occur.

METHODS

A retrospective cohort study using the regional database encompassing NHS organisations across North West London (344 general practitioner [GP] practices, 4 acute hospital trusts and 2 mental health and community health trusts). Patients who had an index admission with ArLD were identified through healthcare coding and compared with a control cohort. Healthcare contacts, blood tests and AUD testing in the year preceding admission were measured.

RESULTS

The ArLD cohort had 1494 participants with an index hospital admission with ArLD. The control cohort included 4462 participants. In the year preceding an index admission with ArLD, 91% of participants had at least one contact with primary care with an average of 2.97 (SD 2.45) contacts; 80% (n = 1199/1494) attended ED, 68% attended an outpatient clinic, and 42% (n = 628/1494) had at least one inpatient admission. Only 9% of the ArLD (137/1494) had formal testing for AUD. Abnormal bilirubin and platelets were more common in the ArLD than the control cohort 25% (138/560) and 28% (231/837), respectively, v 1% (12/1228) and 1% (20/1784).

CONCLUSIONS

Prior to an index admission with ArLD patients have numerous interactions with all healthcare settings, indicating missed opportunities for early identification and treatment.

New nomenclature for fatty liver disease

This review investigates that, in 2023, fatty liver disease underwent a name change to "steatotic liver disease" (SLD). SLD now includes metabolic dysfunction-associated steatotic liver disease (MASLD), alcohol-related liver disease (ALD), and metabolic and alcohol-related liver disease (MetALD). The renaming aims to better incorporate alcohol intake and metabolic risk factors into disease classification and to diminish the stigma associated with the previous nomenclature. Early identification of the patient's aetiology is important for the prognosis which can be improved by interventions against the causative risk factors.

Alcohol-associated liver cancer

Heavy alcohol intake induces a wide spectrum of liver diseases ranging from steatosis, steatohepatitis, cirrhosis, and HCC. Although alcohol consumption is a well-known risk factor for the development, morbidity, and mortality of HCC globally, alcohol-associated hepatocellular carcinoma (A-HCC) is poorly characterized compared to viral hepatitis-associated HCC. Most A-HCCs develop after alcohol-associated cirrhosis (AC), but the direct carcinogenesis from ethanol and its metabolites to A-HCC remains obscure. The differences between A-HCC and HCCs caused by other etiologies have not been well investigated in terms of clinical prognosis, genetic or epigenetic landscape, molecular mechanisms, and heterogeneity. Moreover, there is a huge gap between basic research and clinical practice due to the lack of preclinical models of A-HCC. In the current review, we discuss the pathogenesis, heterogeneity, preclinical approaches, epigenetic, and genetic profiles of A-HCC, and discuss the current insights into and the prospects for future research on A-HCC. The potential effect of alcohol on cholangiocarcinoma and liver metastasis is also discussed.

Impact of MASLD and MetALD on clinical outcomes: A meta-analysis of preliminary evidence

A recent Delphi consensus proposed a new definition for metabolic dysfunction associated steatotic liver disease (MASLD) and introduced a disease entity called MetALD, a condition in which steatotic liver disease (SLD), metabolic dysfunction and moderate alcohol intake coexist. Given the limited available data on the prognostic implications of these disease entities, we performed a systematic review and meta-analysis of available cohort studies to evaluate the association of MASLD and MetALD with hard clinical outcomes. We included 5 studies for a total of 9 824 047 participants. Compared with participants without SLD, increased rates of all-cause mortality and incident cardiovascular disease were present for both MASLD and MetALD. Moreover, MetALD was also associated with significantly higher risks of cancer-related mortality (n = 2 studies, random-effects HR 2.10, 95% CI 1.35-3.28) and cardiovascular mortality (n = 3 studies, random-effects HR 1.17, 95% CI 1.12-1.22). Although preliminary, available evidence indicates a more unfavourable prognosis for patients with MetALD compared with those with MASLD.

Validation of the new nomenclature of steatotic liver disease in patients with a history of excessive alcohol intake: an analysis of data from a prospective cohort study

BACKGROUND

Steatotic liver disease is a new overarching term that includes metabolic dysfunction-associated steatotic liver disease (MASLD), metabolic dysfunction and alcohol-related steatotic liver disease (MetALD), and alcohol-related liver disease (ALD). We aimed to validate the prognostic importance of MASLD, MetALD, and ALD as steatotic liver disease subclasses.

METHODS

Between April 18, 2013, and Sept 17, 2018, we prospectively recruited patients aged 18-75 years with current or previous excessive alcohol intake (>24 g/day for women and >36 g/day for men) for at least a year and no previous hepatic decompensation from the Department of Gastroenterology and Hepatology at Odense University Hospital (Odense, Denmark). Participants were followed up until Sept 15, 2022. Here, we characterise these patients according to steatotic liver disease subclasses. We classified patients as having MASLD, MetALD, or ALD in accordance with the nomenclature definitions, on the basis of metabolic comorbidity and self-reported average alcohol intake in the 3 months leading up to inclusion. Histological scoring was done by a pathologist who was masked to the clinical data. We compared prognoses between classes using Cox regression analyses on hepatic decompensation and overall mortality as the two outcome measures. Patients not meeting the criteria for steatotic liver disease were classified as no steatotic liver disease and served as a reference group.

FINDINGS

We enrolled 446 patients with a history of excessive alcohol intake were included in this analysis (334 [75%] were male and 112 [25%] were female; median age 56 years [SD 10]). Cirrhosis was present in 58 (13%), and 435 (98%) had at least one cardiometabolic risk factor. 321 (72%) met steatotic liver disease criteria and 125 (28%) did not have steatotic liver disease, meaning no evident liver steatosis and no significant fibrosis (≥F2). Of the 321 patients with steatotic liver disease, six (2%) were identified as having ALD due to the absence of cardiometabolic risk factors. The remaining 315 (98%) patients presented with at least one cardiometabolic risk factor. Of these patients, 153 (49%) had MASLD, 76 (24%) had MetALD, and 86 (27%) had ALD. During follow-up, 67 (15%) of 446 patients decompensated and 97 (22%) died (median follow-up 70 months [IQR 53-94]). Patients with steatotic liver disease had a significantly higher risk of hepatic decompensation and overall mortality than those without steatotic liver disease, independent of age, sex, and liver stiffness. The risk of decompensation increased in a stepwise manner from MASLD (hazard ratio 4·73 [95% CI 1·03-21·6]), through MetALD (7·69 [1·66-35·6]), to ALD (10·2 [2·24-46·4]). Similarly, overall mortality increased from MASLD (HR 2·30 [95% CI 1·08-4·90]), through MetALD (2·94 [1·31-6·58]), to ALD (3·57 [1·64-7·80]), independent of age, sex, and liver stiffness.

INTERPRETATION

Steatotic liver disease and its subclasses portend distinct prognoses. There is a need to specify how historical alcohol intake should be integrated into the nomenclature and risk stratification of steatotic liver disease.

FUNDING

EU Horizon 2020 Research and Innovation Program.

Mitochondrial Dysfunction in Metabolic Dysfunction Fatty Liver Disease (MAFLD)

Nonalcoholic fatty liver disease (NAFLD) has become an increasingly common disease in Western countries and has become the major cause of liver cirrhosis or hepatocellular carcinoma (HCC) in addition to viral hepatitis in recent decades. Furthermore, studies have shown that NAFLD is inextricably linked to the development of extrahepatic diseases. However, there is currently no effective treatment to cure NAFLD. In addition, in 2020, NAFLD was renamed metabolic dysfunction fatty liver disease (MAFLD) to show that its pathogenesis is closely related to metabolic disorders. Recent studies have reported that the development of MAFLD is inextricably associated with mitochondrial dysfunction in hepatocytes and hepatic stellate cells (HSCs). Simultaneously, mitochondrial stress caused by structural and functional disorders stimulates the occurrence and accumulation of fat and lipo-toxicity in hepatocytes and HSCs. In addition, the interaction between mitochondrial dysfunction and the liver-gut axis has also become a new point during the development of MAFLD. In this review, we summarize the effects of several potential treatment strategies for MAFLD, including antioxidants, reagents, and intestinal microorganisms and metabolites.

Advances and Controversies in Acute Alcohol-Related Hepatitis: From Medical Therapy to Liver Transplantation

Alcohol-related hepatitis (AH) is a clinical syndrome characterized by recent-onset jaundice in the context of alcohol consumption. In patients with severe AH "unresponsive" to steroid therapy, mortality rates exceed 70% within six months. According to European and American guidelines, liver transplantation (LT) may be considered in highly selected patients who do not respond to medical therapy. The aim of this narrative review is to summarize current knowledge from medical therapy to liver transplantation in acute alcohol-related hepatitis. Due to the impossibility to guarantee six-month abstinence, LT for AH is controversial. Principal concerns are related to organ scarcity in the subset of stigma of "alcohol use disorder" (AUD) and the risk of relapse to alcohol use after LT. Return to alcohol use after LT is a complex issue that cannot be assessed as a yes/no variable with heterogeneous results among studies. In conclusion, present data indicate that well-selected patients have excellent outcomes, with survival rates of up to 100% at 24 and 36 months after LT. Behavioral therapy, ongoing psychological support, and strong family support seem essential to improve long-term outcomes after LT and reduce the risk in relapse of alcohol use.