LONDON ― Around the world, nonalcoholic fatty liver disease (NAFLD) has driven an increase in deaths from liver cancer over the past decade, overtaking alcoholic liver disease, hepatitis B, and hepatitis C, according to an analysis of the Global Burden of Disease Study 2019.
A global rise in liver cancer deaths and chronic liver disease reflects changes in underlying health patterns, said Zobair Younossi, MD, MPH, professor and chair, Department of Medicine, Inova Fairfax Medical Campus, Falls Church, Virginia, who presented the analysis here at the International Liver Congress (ILC) 2022.
“NAFLD and NASH [nonalcoholic steatohepatitis] are rapidly becoming the main causes of cirrhosis and liver cancer in the world,” Younossi told Medscape Medical News. “We have known about the increasing prevalence for some time, but now the outcomes in terms of mortality are catching up,” he said.
“The bottom line of this study is that the burden of this disease [NAFLD] is going up, and it will be the most important disease of the next decade or so,” he said, adding that “the largest annual percentage increase in rates of mortality from liver cancer or chronic liver disease cirrhosis is related to NAFLD.”
Specifically, during the decade of 2009–2019, the annual percent change (APC) of +1.33% in the global liver cancer death rate was driven by the fact that the APC for NAFLD was +2.47%. By comparison, the APC for alcoholic liver disease was +1.91%; for hepatitis B, the APC was +0.21%; and for hepatitis C, the APC was +1.12%.
Aleksander Krag, MD, PhD, professor and senior consultant of hepatology and director of Odense Liver Research Centre at SDU and Odense University Hospital, Denmark, who chaired the session in which this presentation was a part, acknowledged the importance of recognizing the contribution of NAFLD to liver cancer mortality.
“Liver diseases are on the rise. They are the fastest rising cause of death in the United Kingdom, faster than heart disease and other cancers. NAFLD in particular is the fastest growing cause of liver cancer, and the leading cause in France and the United States,” he remarked.
Krag also highlighted the costs of disease management.
“Managing fatty liver disease in Europe is estimated at €35 billion in direct healthcare, so we need to do something now,” he stressed.
“The global burden of NAFLD is so high that we need both prevention and treatment tools,” Krag said. “Change to lifestyle is a ‘no-brainer’ and costs governments very little. For the sake of our young people, we need to take this very seriously. At a political level, we can easily implement this, for example, by banning junk food advertisements, but also educating young people and their families. Good drugs will also help.”
NAFLD: The Liver Manifestation of Type 2 Diabetes
About 25% to 30% of the global population have NAFLD, and 3% to 5% have NASH. Younossi highlighted that the US transplant database shows that NAFLD was the second indication for all liver transplants in the country. NAFLD also was the top indication for hepatocellular carcinoma.
There are around two billion cases of chronic liver disease globally, he said. He noted that over time, there has been an increase in all kinds of liver diseases, as reflected in the annual percent change.
“The global epidemic of obesity and type 2 diabetes is driving the rise in NAFLD, but even among lean people, the prevalence of NAFLD is around 9%,” Younossi said. “Alongside the eye and kidney complications of diabetes, this is the liver manifestation of type 2 diabetes.”
To assess global liver disease and death, Younossi and his colleagues turned to the Global Burden of Disease Study, which gathered data from around 7000 investigators located across 22 different regions of the world, comprising 156 countries.
They calculated the incidence, prevalence, mortality, and disability-adjusted life-years (DALYs) in relation to liver cancer and chronic liver disease, including the APC. They linked the data to changes in four liver diseases: NAFLD, alcoholic liver disease, hepatitis B infection, and hepatitis C infection.
The cases of NAFLD reported in the study had been diagnosed by ultrasound or other imaging. Importantly, the prevalence of NAFLD was adjusted for alcohol use in the various national populations, explained Younossi.
In 2019, they reported that globally, the overall prevalence of liver disease reached 1.69 billion (liver cancer, 0.04%; chronic liver disease, 99.96%), with an incidence of 2.59 million (liver cancer, 20.7%; chronic liver disease, 79.3%), mortality of 1.95 million (liver cancer, 24.8%; chronic liver disease, 75.3%), and DALYs of 58.7 million (liver cancer, 21.3%; chronic liver disease, 78.7%).
Between 2009 and 2019, deaths from liver cancer rose by 27.2%, and deaths from chronic liver disease rose by 10.6%. DALYs from liver cancer rose by 21.9%, and DALYs from chronic liver disease were up by 5.1%.
In contrast to the increase in liver cancer deaths, deaths from chronic liver disease decreased (APC, -0.18%). The decrease was driven by a decrease in hepatitis B (APC, -1.83%). APCs for hepatitis C (+0.37%), alcoholic liver disease (+0.45%), and NAFLD (+1.33%) increased.
“The burden of hepatitis B–related mortality has decreased because we have been so good at vaccinating people,” Younossi remarked.
NAFLD “Exploding” in Middle East, North Africa, and East Asia
The increase in NAFLD has been seen in all regions of the world, but a breakdown by region shows that NAFLD is primarily “exploding” with highest prevalence and mortality in the Middle East (mostly Egypt, Iran, and Turkey), North Africa, and East Asia, said Younossi. In addition, there are large increases in the West and South America.
“We knew that the prevalence was high in the Middle East, but we now know that mortality is also high, so we are connecting these data,” said Younossi.
Younossi pressed the fact that awareness among the general population, primary care providers, and policymakers is very low. “From my perspective, raising awareness of NAFLD is the number one priority, and that is the value of this study.”
He added that more people will become aware as testing becomes more manageable.
“There are some noninvasive tests being developed, so in the future, we won’t have to do liver biopsies to diagnose these patients,” he said. “Currently, there are some excellent treatments being developed.”
“The WHO [World Health Organization] does not mention NAFLD as an important noncommunicable disease, and this too has to change,” Younossi added.
International Liver Congress (ILC) 2022: Abstract GS008. Presented June 24, 2022.
Younossi has received research runds and/or has consulted for Abbott, Allergan, Bristol-Myers Squibb, Echosens, Genfit, Gilead Sciences, Intercept, Madrigal, Merck, and Novo Nordisk. Karg has disclosed no relevant financial relationships.