This website is intended for US Healthcare Professionals.
Learn more about MASH
About MASH
Reported estimates suggest that 5% of adults in the US have MASH. The number of adults with MASH is projected to increase 63% from 16.5 million cases in 2015 to 27 million in 2030.1,2
In 2023, a consensus on a nomenclature change was developed by a multistakeholder effort including the American Association for the Study of Liver Diseases (AASLD) and the European Association for the Study of the Liver (EASL). The name chosen to replace nonalcoholic fatty liver disease (NAFLD) was metabolic dysfunction-associated steatotic liver disease (MASLD), while nonalcoholic steatohepatitis (NASH) was replaced with metabolic dysfunction-associated steatohepatitis (MASH).3
The new nomenclature was chosen to more accurately reflect the metabolic basis for the disease, which was long recognized as “the hepatic manifestation of metabolic syndrome.” The panel suggested that this would allow for easier, more intuitive explanations of the disease to patients, eliminate potential stigma surrounding the original name, and potentially improve disease awareness by aligning the name to its widely recognized traits.3
On average, one stage of fibrosis progression takes around 7 years, but some people with MASH can progress from F0 to advanced fibrosis or cirrhosis (F3-F4) in less than 6 years.4,5
Additionally, as many as 1 in 4 patients with MASH may progress to liver cirrhosis (F4) within 10 to 15 years.6
If MASH progresses, it can increase the risk of significant complications such as, but not limited to, hepatic decompensation, hepatocellular carcinoma (HCC), liver-related morbidity and all-cause mortality, cardiovascular disease, and cirrhosis-related death.7-11
Because MASLD is closely linked to the development of other metabolic abnormalities, patients who are at risk of advanced fibrosis include those with metabolic syndrome, type 2 diabetes (T2D), medically complicated obesity, MASLD with moderate alcohol use, and a first-degree relative with cirrhosis due to MASLD/MASH. Patients with a FIB-4 score >2.67 are also at high risk of advanced fibrosis.7
Screening & Diagnosing
The AASLD recommends screening for patients at high risk for advanced fibrosis, including those with cardiometabolic risk factors including T2D, medically complicated obesity, more than mild alcohol consumption, and family history of cirrhosis.7
According to the AASLD, all patients with obesity and metabolic risk factors should undergo primary risk assessment with the FIB-4 test to evaluate the risk of clinically significant fibrosis.7
In patients with prediabetes, T2D, or 2 or more metabolic risk factors (or imaging evidence of hepatic steatosis), it is recommended to perform primary risk assessment with FIB-4 every 1–2 years.7
Yes. Due to the close link between MASLD and metabolic abnormalities, the AASLD recommends that all patients with obesity and metabolic risk factors undergo primary risk assessment with the FIB-4 test to evaluate the risk of clinically significant fibrosis.7
MASLD and its more severe form, MASH, are closely linked to the development of other metabolic abnormalities such as insulin resistance, dyslipidemia, central obesity, and hypertension.7,12
This association is believed to be reflective of the interactions between the liver and other endocrine organs that regulate fatty acid metabolism, insulin action, and glucose metabolism.7
There is no single test to diagnose MASH. While liver biopsy assessment is considered the standard for grading and staging MASH, it is not consistently performed due to its invasive nature and prohibitive cost. As a result, there is a need for noninvasive tests (NITs) to diagnose MASH.7
Primary risk assessment with FIB-4 is recommended for patients who7:
- Have hepatic steatosis
- Are suspected to have MASLD based on the presence of obesity and metabolic risk factors
Patients with an elevated FIB-4 (≥1.3) should undergo secondary risk assessment with vibration-controlled transient elastography or the serum-based Enhanced Liver Fibrosis™ (ELF™) test to identify advanced fibrosis.7
No. While patients with MASLD are commonly referred based on elevated liver chemistries, normal values provided by most laboratories are higher than what should be considered normal for MASLD. In patients with MASLD, true normal alanine aminotransferase (ALT) ranges from 29 to 33 U/L in men and from 19 to 25 U/L in women.7
Similarly, serum aspartate aminotransferase (AST) levels used to identify liver disease can appear normal in patients with MASH. AST levels are neither sensitive nor specific for the identification of MASLD/MASH with advanced fibrosis.7
Management
While there are limited FDA-approved drugs for the treatment of MASH, the AASLD recommends lifestyle interventions, such as changes in diet and exercise, to promote cardiovascular health and address metabolic comorbidities. A multidisciplinary team of clinicians monitoring these lifestyle interventions is also recommended to optimize the management of metabolic comorbid disease and reduce morbidity and mortality in patients with MASLD.7
A healthy diet and regular exercise are recommended by the AASLD as the foundation of treatment for the vast majority of patients with MASLD.7
Weight loss has been shown to improve steatosis in patients with milder disease and MASH and fibrosis.7
Vigorous exercise has been shown to improve MASH histology and reduce fibrosis. Studies combining exercise with diet consistently demonstrate reductions in liver fat proportional to the intensity of the intervention.7
References:
- Younossi ZM, Golabi P, Paik JM, et al. The global epidemiology of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH): a systematic review. Hepatology. 2023;77(4):1335-1347.
- Estes C, Razavi H, Loomba R, et al. Modeling the epidemic of nonalcoholic fatty liver disease demonstrates an exponential increase in burden of disease. Hepatology. 2018;67(1):123–133.
- Rinella ME, Lazarus JV, Ratziu V, et al. NAFLD Nomenclature consensus group. A multisociety Delphi consensus statement on new fatty liver disease nomenclature. J Hepatol. 2023;79(6):1542–1556.
- Marengo A, Jouness RIK, Bugianesi E, et al. Progression and natural history of nonalcoholic fatty liver disease in adults. Clin Liver Dis. 2016;20(2):313–324.
- Loomba R, Adams LA. The 20% rule of NASH progression: the natural history of advanced fibrosis and cirrhosis caused by NASH. Hepatology. 2019;70(6):1885–1888.
- Shi YW, Fan JG. Current status and challenges in the drug treatment for fibrotic nonalcoholic steatohepatitis. Acta Pharmacologica Sinica. 2022;43:1191–1199.
- Rinella ME, Neuschwander-Tetri BA, Siddiqui MS, et al. AASLD practice guidance on the clinical assessment and management of nonalcoholic fatty liver disease. Hepatol. 2023;77(5):1797–1835.
- Younossi ZM, Henry L. Epidemiology of non-alcoholic fatty liver disease and hepatocellular carcinoma. JHEP Rep. 2021;11;3(4):100305.
- Targher G, Byrne CD, Tilg H, et al. NAFLD and increased risk of cardiovascular disease: clinical associations, pathophysiological mechanisms and pharmacological implications. Gut. 2020;69(9):1691–1705.
- Dulai PS, Singh S, Patel J, et al. Increased risk of mortality by fibrosis stage in nonalcoholic fatty liver disease: Systematic review and meta-analysis. Hepatology. 2017;65(5):1557–1565.
- Paik JM, Henry L, De Avila L, et al. Mortality related to nonalcoholic fatty liver disease is increasing in the United States. Hepatol Commun. 2019;3(11):1459-1471.
- Chalasani N, Younossi Z, Lavine JE, et al. The diagnosis and management of nonalcoholic fatty liver disease: Practice guidance from the American Association for the Study of Liver Diseases. Hepatology. 2018;67(1):328-357.
