In his session at the 21st Annual Harvard Nutrition and Obesity Symposium on Nonalcoholic Fatty Liver Disease (NAFLD), Zobair Younossi, MD, from Inova Fairfax Medical Campus, shed light on the global burden of NAFLD and nonalcoholic steatohepatitis (NASH), a potentially progressive form of NAFLD.

Dr Younossi first characterized 4 types of comprehensive burden: clinical (mortality outcomes), PRO (patient experience outcomes), functional (functional outcomes), and economic (resource utilization outcomes).

“NASH has significant and growing clinical, economic, and quality of life burden,” Dr Younossi said.

He explained that the worldwide prevalence of NAFLD is estimated at 25%. The locations with the highest prevalence of NAFLD are the Middle East (31.8%), South America (30.5%), Asia (27.4%), North America (24.1%), Europe (23.7%), and Africa (13.5%).

Dr Younossi went on to discuss multiple studies that showed NAFLD is growing in prevalence in Europe, Asia, the Middle East, Africa, North and South America, and Australia. In the United States, Dr Younossi and colleagues¹ evaluated NHANES data from 1988 to 2016 and found that NAFLD is the only liver disease that has grown, and is continuously growing, in prevalence. This coincides with increases in prevalence of obesity, type 2 diabetes mellitus, insulin resistance, and hypertension.

It is well known that NAFLD and NASH are multisystemic diseases related to metabolic abnormalities, including obesity and type 2 diabetes mellitus. However, NALFD can also present in lean, metabolically normal (defined as having a normal body mass index and no metabolic disease) individuals. Among metabolically normal individuals, 10.8% of the lean cohort of NHANES had NAFLD. Moreover, another study² found that the global prevalence of NAFLD among individuals with type 2 diabetes mellitus is about 55.5%.

Dr Younossi went on to discuss age-standardized cause-specific death rates among US-based individuals with NAFLD from 2007 to 2016.³ Hepatocellular carcinoma attributed to 16.6% of liver-related deaths, and cirrhosis contributed to 82.0% of liver-related deaths. The study findings attributed the primary drivers of the rising burden of hepatocellular carcinoma and cirrhosis to NAFLD and alcoholic liver disease.

“NASH is rapidly becoming the most common cause of liver disease in the world,” Dr Younossi concluded. “[It is] the most common cause of cirrhosis in a number of countries, commonly the cause of [hepatocellular carcinoma], and the second most common indication for [liver transplant] in the US and the top indication among women.”

—Amanda Balbi

REFERENCES:

1. Younossi ZM, Stepanova M, Younossi Y, et al. Epidemiology of chronic liver diseases in the USA in the past three decades. Gut. Published online February 7, 2020. https://gut.bmj.com/content/69/3/564
2. Younossi ZM, Tampi RP, Racila A, et al. Economic and clinical burden of nonalcoholic steatohepatitis in patients with type 2 diabetes in the US. Diabetes Care. 2020;43(2):283-289. https://care.diabetesjournals.org/content/43/2/283
3. Paik JM, Golabi P, Biswas R, Alqahtani S, Venkatesan C, Younossi ZM. Nonalcoholic fatty liver disease and alcoholic liver disease are major drivers of liver mortality in the United States. Hepatol Communications. Published online April 4, 2020. https://aasldpubs.onlinelibrary.wiley.com/doi/full/10.1002/hep4.1510