BOSTON – A sophisticated mathematical analysis shows that nonalcoholic fatty liver disease is costing the United States over $290 billion annually. A similar economic burden was seen in several Western European countries as well.
The study, which incorporated available data about current cases of nonalcoholic fatty liver disease (NAFLD), looked at both medical and nonmedical costs, as the disease’s economic and social impact extends far beyond medical bills.
“It impacts patients’ quality of life, their work productivity; there’s a significant fatigue associated with that. In addition to this, there is an economic burden of nonalcoholic fatty liver disease,” said the study’s lead author, Zobair Younossi, MD, in a video interview at the annual meeting of the American Association for the Study of Liver Diseases.
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Dr. Younossi, executive director of the Center for Liver Diseases at Inova Fairfax Hospital, Falls Church, Va., and his coinvestigators constructed a Markov chain to model costs associated with NAFLD. This mathematical technique allows the probability of the occurrence of an event to influence the model’s prediction of the probability of later events, a useful technique when trying to model real-world, dynamic conditions.
They used the Markov chain technique to model the transition of patients along the path of NAFLD progression. States included in the model were nonalcoholic steatohepatitis (NASH), NASH with fibrosis, compensated and decompensated cirrhosis, hepatocellular carcinoma, transplant, posttransplant, and death. The probabilities of progressing through these states were built from a meta-analysis and systematic literature review conducted by the authors, which they then adjusted by incorporating real-world data.
According to the model, annual direct medical costs are projected at $103 billion, or $1,613 for each of the 64 million NAFLD patients in the United States. The four European Union countries included in the model were Germany, France, Italy, and the United Kingdom. In aggregate, these countries are projected to have about 52 million people with NAFLD, for an annual cost of 35 billion euros. The estimated annual direct cost per patient varies by country, ranging from 354 euros to 1,163 euros.
When societal costs are incorporated, the numbers leap higher: to $292.19 billion in the United States, and over 200 billion euros in the four European countries studied.
In recent work, Dr. Younossi and his colleagues have reached an estimate that about a quarter of the world’s population has NAFLD. He said he was surprised to learn that the highest prevalences were in some areas of South America and the Middle East, with rapid increases in Asia as well.
However, the etiology of NAFLD helps explain these increases. “It’s really a phenotype. A number of different pathways lead to this disease; the most common is the one that is associated with obesity, type 2 diabetes, and insulin resistance,” said Dr. Younossi.
The subset of NAFLD patients who have NASH also risks progression to cirrhosis and hepatocellular carcinoma. According to Dr. Younossi’s examination of the UNOS transplant database, NASH is the second leading cause of liver transplantation in the United States, and one of the top three causes of death from liver disease.
These sobering data make the need for medical treatment for NASH an urgent priority, said Dr. Younossi. Currently, lifestyle modification such as weight loss is the only known treatment for NAFLD and NASH, “which is not easy to do,” he noted.
Several candidate drugs are in the pipeline currently. Also, said Dr. Younossi, NASH can be diagnosed only by liver biopsy currently, a risky and expensive procedure. The search is on for accurate and reliable imaging and serum biomarkers for NASH, so physicians can understand who’s most at risk for progression to more serious liver disease.
“The analysis quantifies the enormity of the clinical and economic burden of NAFLD, which will likely increase as incidence of NAFLD continues to rise with the increasing obesity and diabetes rates,” wrote Dr. Younossi and his coauthors.
Dr. Younossi reported having financial relationships with several pharmaceutical companies.
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