Nonalcoholic fatty liver disease epidemic increasing greatly

Reuters Health Information: Nonalcoholic fatty liver disease epidemic increasing greatly

Nonalcoholic fatty liver disease epidemic increasing greatly

Last Updated: 2017-08-30

By Will Boggs MD

NEW YORK (Reuters Health) - The burden of nonalcoholic fatty liver disease (NAFLD) is increasing greatly, and the need for liver transplants is likely to outstrip the supply of donors, researchers report.

NAFLD includes nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH), which is an increasingly common cause of end-stage liver disease and is the second most common cause of hepatocellular carcinoma (HCC) requiring liver transplantation.

Chris Estes from the Center for Disease Analysis, Lafayette, Colorado, and colleagues developed a dynamic Markov model of NAFLD to assess the population health burden of the disease so that its healthcare impact can be forecast.

Their model predicts that the total NAFLD population will increase from an estimated 83.1 million cases (30.0% prevalence among people age 15 or older, 25.8% prevalence among all ages) in 2015 to 100.9 million cases (33.5% and 28.4%, respectively) by 2030.

During this interval, males with NAFLD are expected to outnumber females with NAFLD by 20%, according to the August 12 Hepatology online report.

The number of NASH cases is projected to increase by 63%, from about 16.5 million cases in 2015 to 27 million cases in 2030. Those with advanced liver disease will increase by an estimated 160%, from about 3.3 million cases in 2015 to 7.9 million cases in 2030, with compensated cirrhosis cases climbing to 3.1 million by 2030.

By 2030, the prevalence of decompensated cirrhosis will have increased by 180% (to 376,100 cases), resulting in an estimated increase of 59% in liver transplant cases (reaching 7,610 by 2030).

The model predicts a cumulative HCC incidence between 2015 and 2030 of 135,000 cases.

Total deaths among the NAFLD population are projected to increase by 44%, to 1.83 million annually, by 2030. About 12.5% of these will be excess cardiovascular deaths and about 3% excess liver-related mortality. Fewer than 1% of liver deaths are projected to occur among the liver transplant population.

The researchers note that the increase in the number of people eligible for liver transplant may outpace the supply of organs and influence their availability for other liver diseases. Even without the need for liver transplantation, the management of cirrhosis is a resource-intense drain on hospital resources.

"I hope other physicians will understand the magnitude of the liver disease we will see as fatty liver disease becomes the most common indication for liver transplantation in the U.S.," Dr. Neehar D. Parikh from University of Michigan, Ann Arbor, told Reuters Health by email.

Dr. Parikh and colleagues, in a related report, used data from the Organ Procurement and Transplantation Network, the Continuous National Health and Nutrition Examination Survey, and the U.S. Census Bureau to develop a linear regression model that examined the association between obesity and NASH additions to liver transplantation waitlists.

Between 2000 and 2014, the population of obese people increased by 44.9%, and NASH-related additions to the waitlist increased more than fourfold. Additions to the waitlist were best predicted by the prevalence of obesity 9 years earlier.

With the anticipated increase in the obese population (to more than 92 million adults by 2025), the number of NASH-related waitlist additions is also expected to increase by 55.4% (to 2,104 by 2030).

"In the hepatology community, there is a sense that fatty liver will be an enormous problem in the United States, and so our article gives objective data to back up that sense and a clear estimate of what we will be facing in the future if obesity trends in the U.S. continue to be on the trajectory they have been," Dr. Parikh said by email.

"There needs to be continued public health effort to reduce obesity rates," he said. "Our sensitivity analysis shows that if obesity in the U.S. increases as it has over the past 15 years, we will see the fatty liver-related liver transplant waiting list additions increase from a 55.4% increase to a 71.9% increase, which is quite dramatic. The fatty liver epidemic will only get worse without efforts to reduce obesity."

Dr. Zobair M. Younossi from Inova Health System and Beatty Center for Integrated Research, Falls Church, Virginia, told Reuters Health by email, "It is important to recognize that this is an important cause of liver disease and will be causing a higher burden in the future. Therefore, clinicians who see patients with fatty liver by imaging techniques or see patients with very mild liver enzyme elevations cannot discount these patients. They need to understand that there are ways to risk-stratify these patients with NAFLD and refer patients with potentially progressive form of NAFLD to be co-managed by specialized centers."

He offers several suggestions to address this ongoing challenge: raising awareness about NAFLD among medical professionals, policy makers, and the public; better noninvasive tests to accurately predict who will and who will not progress to advanced liver disease; and better treatment modalities, including more-effective strategies for lifestyle modification.

Estes did not respond to a request for comment.

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Hepatology 2017.

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