Nonalcoholic Liver Disease ‘an Epidemic of the 21st Century’

The way Christos S. Mantzoros, MD, DSc, PhD, sees it, nonalcoholic steatohepatitis (NASH) is an epidemic of the 21st century that can trigger a cascade of reactions.
“If more than 5.8% of fat is in the liver, we call it nonalcoholic fatty liver disease [NAFLD],” Dr. Mantzoros, professor of medicine at Harvard Medical School, Boston, and Boston University, explained at the World Congress on Insulin Resistance, Diabetes, and Cardiovascular Disease. “If inflammation develops to remove the fat, we call it NASH. If this progresses to decompensated reaction and fibrosis and cirrhosis, then we call it nonalcoholic steatohepatitis with fibrosis. That can lead to liver cirrhosis, hepatocellular carcinoma, and liver failure.”
The underlying problem stems from the rise in obesity prevalence, according to Dr. Mantzoros, who is also chief of endocrinology at the Boston Veterans Affairs Healthcare System. For 75%-80% of individuals with metabolically unhealthy obesity, the storage space in their adipose tissue is exceeded. “Fat is deposited into muscle, causing insulin resistance, and into the liver,” he explained. “If it’s more than 5.8%, it causes NAFLD. Most of us don’t realize that most of the patients with diabetes we have in our clinics also have nonalcoholic fatty liver disease. That’s because we don’t have an easy diagnostic tool or an easy treatment. It’s an unmet clinical need.” (There are currently no drugs approved for the treatment of NASH or NAFLD. Current recommended first-line treatment is weight loss through diet and exercise and control of diabetes, if it is present.)
“Assuming the rate of increase in cost due to NAFLD parallels the growth in obesity, the 10-year projection for direct cost is $1.005 trillion,” said Dr. Mantzoros, who is also editor in chief of the journal Metabolism. “Obesity, NAFLD, and insulin resistance are each independently associated with a twofold risk for diabetes. If all three are present, there is a 14-fold risk for diabetes. Insulin resistance promotes an increase in free fatty acid traffic to the liver, which can trigger hepatic lipotoxicity. Hyperinsulinemia enhances free fatty acid uptake and activates de novo lipogenesis. Hyperglycemia can also activate de novo lipogenesis.”

About 85 million Americans have NAFLD, he continued. Most (80%) are cases of steatosis, but 20% have NASH. Of those, 20% develop advanced fibrosis, which leads to liver failure and transplantation or death. A study of data from the National Health and Nutrition Examination Survey found that diabetes was the strongest predictor of advanced fibrosis in patients with NAFLD (odds ratio, 18.20), followed by a body mass index of 30 kg/m² or greater (OR, 9.10), hypertension (OR, 1.20), and age (OR, 1.08; Ailment Pharmacol Ther. 2017;46:974-80). “Most of the patients who come to our clinics with diabetes have nonalcoholic fatty liver disease – 75%-80% in our clinics, and about 10% have advanced fibrosis,” Dr. Mantzoros said. “Most of them go undiagnosed.”
Patients with type 2 diabetes and NAFLD progress faster to fibrosis and end-stage liver disease, compared with those who do not have diabetes. One study of 108 patients with biopsy-proven NALFD showed that 84% of those with fibrosis progression had type 2 diabetes (J Hepatol. 2015;62:1148-55). Other findings have shown that patients with type 2 diabetes are at increased risk of chronic NAFLD and hepatocellular carcinoma (Gastroenterol. 2001;126:460-8). “We are doing more liver transplantations because of NAFLD and NASH than because of hepatitis C,” Dr. Mantzoros said. “What we need to keep in mind is that, although liver morbidity and mortality is important, this is a component of the cardiometabolic syndrome. So, people have all the risk factors for cardiovascular disease. Because CVD is much more common, people with NAFLD suffer from and die from CVD. The more advanced the NAFLD, the higher the risk of death from cardiovascular disease.”
https://www.medscape.com/viewarticle/924818