Fatty liver (MASLD): many metabolic factors, many courses

Summary: Fatty liver disease (MASLD) is not one uniform condition: how many and which metabolic disorders come on top shapes the risk to liver, heart and kidneys. Type 2 diabetes and high blood pressure weigh most. A review in Nature Reviews Gastroenterology & Hepatology describes the mechanisms and proposes a holistic treatment model that treats liver and metabolism together.

State of the evidence: The review appeared in volume 22 (May 2025) of the journal, with a corrected version in 2026. It presents studies up to 2024 and 2025, including interim results of a phase 3 trial. No systematic literature search is described. This article was written on 17 October 2026; newer studies are not included.

What is it about?

MASLD (metabolic dysfunction-associated steatotic liver disease, formerly NAFLD) means fat in the liver plus at least one of five metabolic factors of the metabolic syndrome: large waist, high blood pressure, high blood fats (triglycerides), low HDL cholesterol and raised blood sugar. Some people have just one, others all five. The authors ask how this affects risk, disease development and treatment.

How was it studied?

This is a review by Byrne, Armandi, Pellegrinelli, Vidal-Puig and Bugianesi (Southampton, Turin, Cambridge, Valencia), not a new patient study. It evaluates cohorts, meta-analyses and drug trials and derives a care model from them.

What does the review show?

• Diabetes weighs most: In a meta-analysis of 18 studies with 22.8 million people, type 2 diabetes roughly doubled the risk of liver disease (risk ratio 2.25). Obesity raised it less (1.20). People with type 2 diabetes have about a threefold higher risk of liver cancer than the general population.
• More factors, more risk: In a Swedish cohort of 230,992 people with type 2 diabetes, high blood pressure was the strongest single factor for severe liver complications; the combination of high blood pressure, obesity, protein in the urine, high blood fats and low HDL cholesterol carried the highest risk.
• The heart stays important: In a cohort of 1,773 people with MASLD, about 40% of deaths were from cardiovascular disease, about 20% from cancer outside the liver and about 10% from the liver. With cirrhosis, the liver comes first.
• Diabetes amplifies MASLD: In a Korean cohort of more than 7.7 million people, type 2 diabetes on top of MASLD raised the risk of cardiovascular disease and death further.
• Genes and family: Variants in genes such as PNPLA3, TM6SF2 and GCKR shape the course. First-degree relatives of people with MASH cirrhosis have a 12-fold higher risk of advanced fibrosis.
• Alcohol counts: Even moderate intake can, together with metabolic factors, raise the risk of fibrosis strongly. With advanced fibrosis or cirrhosis, alcohol should be avoided completely.
• Stepwise diagnosis: The FIB-4 index comes first, then an ultrasound-based liver stiffness measurement (VCTE). People whose stiffness rises from below 10 to 10 kPa or more have a fourfold higher risk of liver events.
• Treatment on several paths: A Mediterranean diet, exercise and statins (safe, but prescribed too rarely) remain the base. Resmetirom is provisionally approved in the US for MASH with fibrosis. In an interim analysis, MASH resolved in 62.9% on semaglutide (placebo 34.1%), and weight fell by 10.5% (placebo 2.0%). Other agents such as tirzepatide, survodutide and retatrutide clearly lowered liver fat and weight in early trials.
• Heart and kidneys benefit: In a trial without diabetes, semaglutide reduced major cardiovascular events (6.5% versus 8.0%; hazard ratio 0.80). In type 2 diabetes, users of GLP-1 drugs in Swedish registry data had half as many major liver events after ten years (7.4% versus 14.4%).

Where are the limits?

• This is a review, not a systematic analysis; the authors chose the evidence.
• Which combination of metabolic factors carries the highest risk is still unclear, according to the authors.
• Many of the data come from observational studies and cannot prove cause and effect. Proxy measures of liver fat that themselves contain metabolic factors can skew results.
• The semaglutide results are an interim analysis; several new agents are only in early trial phases. Single-target drugs have mostly failed so far, so combinations are probably needed.
• The definition of MASLD is not accepted everywhere.

What does this mean for me?

The review describes groups and says nothing about your personal risk. It does show that with fatty liver, blood sugar, blood pressure, blood fats, weight and alcohol matter as much as liver tests. If you have type 2 diabetes or high blood pressure, you can ask your family doctor to assess your fibrosis risk. Discuss with your doctor which tests and treatments make sense for you.

This article does not replace medical advice.

Source and notes

• Citation: Byrne CD, Armandi A, Pellegrinelli V, Vidal-Puig A, Bugianesi E. Metabolic dysfunction-associated steatotic liver disease: a condition of heterogeneous metabolic risk factors, mechanisms and comorbidities requiring holistic treatment. Nat Rev Gastroenterol Hepatol 2025;22:314–328. DOI: 10.1038/s41575-025-01045-z.
• Study type: Review article.
• Funding: The authors are supported, among others, by the National Institute for Health and Care Research Southampton Biomedical Research Centre, the Italian Ministry of Education and Research, the EU (NextGenerationEU) and the IMI programme LITMUS.
• Conflicts of interest: Christopher Byrne received research funding from Echosens. Elisabetta Bugianesi served as a consultant for Boehringer, MSD, Novo Nordisk and Pfizer, as a speaker for MSD, Novo Nordisk and Madrigal, and received research grants from Gilead Sciences. The other authors report no competing interests.