Over 90% of obese, 60% of diabetic, and up to 20% of normal-weight people develop it. NAFLD is the leading cause of chronic liver disease and the second most common reason for liver transplantation in the US and Europe as of 2017. NAFLD affects about 20 to 25% of people in Europe. In the United States, estimates suggest between 30 and 40% of adults have NAFLD, and about 3 to 12% of adults have NASH. The annual economic burden was approximately US$103 billion in the US in 2016. Definition
An abnormal accumulation of fat in the liver in the absence of secondary causes of fatty liver, such as significant alcohol use, viral hepatitis, or medications that can induce fatty liver characterizes non-alcoholic fatty liver disease (NAFLD). The term NAFLD encompasses a continuum of liver abnormalities, from non-alcoholic fatty liver (NAFL, simple steatosis) to non-alcoholic steatohepatitis (NASH). These diseases begin with fatty accumulation in the liver (hepatic steatosis). A liver can remain fatty without disturbing liver function (NAFL), but by various mechanisms and possible insults to the liver, it may also progress into non-alcoholic steatohepatitis (NASH), a state in which steatosis is combined with inflammation and sometimes fibrosis (steatohepatitis). NASH can then lead to complications such as cirrhosis and hepatocellular carcinoma.A new name, metabolic dysfunction associated fatty liver disease, was proposed after 70% of a panel of experts expressed support for this name.
Medication
Treatment with medications is primarily aimed at improving liver disease and is generally limited to those with biopsy-proven NASH and fibrosis.No medicines specifically for NAFLD or NASH had received approval, as of 2018, although anti-diabetic medications may help in liver fat loss. While many treatments appear to improve biochemical markers such as alanine transaminase levels, most do not reverse histological abnormalities or improve outcomes.Insulin sensitizers (metformin and thiazolidinediones, such as pioglitazone) and liraglutide are not specifically recommended for NAFLD as they do not directly improve the liver condition. They can be indicated for diabetic individuals, after a careful assessment of risks, to reduce insulin resistance and risks of complications. Indeed, the side effects associated with thiazolidinedione medications, which include osteopenia, increased fracture risk, fluid retention, congestive heart failure, bladder cancer, and long-term weight gain, have limited their adoption. Due to these side effects, the AASLD recommends the use of pioglitazone only for individuals with biopsy-proven NASH, and the Asia-Pacific Work Group recommends them only for individuals with NAFLD with known diabetic issues. However, the AASLD advises against the use of metformin as studies were inconclusive about the improvement of the livers histological condition. Although there was an improvement in insulin resistance and serum aminotransferases, this did not translate into NASH improvements.