New definition of fatty liver disease indicates higher risk of death
Using data, including associated mortality, from participants in a national survey, researchers found that people who met the definition of fatty liver disease associated with metabolic dysfunction (MAFLD) had worse mortality than those who met the definition of fatty liver disease associated with metabolic dysfunction (MAFLD). met the traditional definition of non-alcoholic fatty liver disease. (NAFLD). These results were published in the Journal of Hepatology.
Resulting from the accumulation of fat in the liver, NAFLD and its most severe form, non-alcoholic steatohepatitis (NASH), are responsible for an increasing proportion of advanced liver disease worldwide. Due to inflammation, NAFLD can lead to buildup of scar tissue (fibrosis), cirrhosis (advanced scarring), and even liver cancer. Fatty liver disease is often accompanied by abdominal obesity, hypertension, high blood sugar, and abnormal levels of fat in the blood, collectively known as metabolic syndrome. In the absence of effective and approved medical therapies, disease management depends on lifestyle changes, such as weight loss and exercise.
Previously, researchers proposed to broaden the definition of NAFLD to better reflect its characteristics and to rename fatty liver disease associated with metabolism. But changing the criteria may affect known death rates. Donghee Kim, MD, PhD, Stanford University School of Medicine, California, and colleagues explored the differences in death rates associated with MAFLD and NAFLD in an adult population in the United States.
The researchers preselected data from the Third National Health and Nutrition Survey (1988 to 1994) on 7,761 people, as well as their information on mortality up to 2015. The presence of liver fat, detected by ultrasound, has been used to diagnose NAFLD in the absence of binge drinking and viral hepatitis. MAFLD status was determined on the basis of specific criteria put forward by a panel of experts, including the presence of hepatic fat plus at least one of the other three criteria: overweight or obesity, diabetes and at least two metabolic abnormalities.
In the entire study population, approximately 30% had NAFLD and 26% had MAFLD. About 24% met the criteria for both conditions. During follow-up, there were 2,234 deaths, of which 574 were from cardiovascular causes and 556 from cancer.
Over 23 years, researchers noted that people with MAFLD had a 17% higher risk of death from all causes. For people with MAFLD, the all-cause mortality was 2.2 times that of those without MAFLD. In several models, MAFLD was linked to higher all-cause mortality. On the other hand, NAFLD was not associated with all-cause mortality after adjusting for metabolic risk factors. People with MAFLD and severe fibrosis had higher all-cause mortality than those with NAFLD and advanced fibrosis.
MAFLD was also linked to an increased risk of cardiovascular death. People with MAFLD experienced 24% higher cardiovascular mortality than others, but this association weakened after adjusting for metabolic factors. No significant association was found between NAFLD alone and cardiovascular mortality.
People with MAFLD in the absence of NAFLD had a 1.7-fold increased risk of all-cause mortality. But a similar risk has not been observed in people with NAFLD but not MAFLD or in those with simple steatosis (accumulation of fat in the liver). People who met the criteria for NAFLD and MAFLD had a 13% higher risk of death from all causes.
“Our results support the idea that non-alcoholic fatty liver disease (NAFLD) is part of a larger multisystem disease that also includes obesity, diabetes, high blood pressure and high cholesterol,” the researchers wrote. “Therefore, redefining NAFLD as fatty liver disease associated with metabolic dysfunction (MAFLD) may provide a better understanding of predictors that may increase the risk of death.”
Click here to read the study summary in the Journal of Hepatology.