SAN FRANCISCO –
Dr. Zobair M. Younossi
“I believe it’s all related to a big increase in obesity and type 2 diabetes in this country,” lead study author Zobair M. Younossi, MD, MPH, said in an interview in advance of the annual meeting of the American Association for the Study of Liver Diseases. “Those two risk factors drive NAFLD and its progressive type, nonalcoholic steatohepatitis (NASH). That accounts for at least part of the increase in mortality related to liver disease.”
In an effort to evaluate recent mortality trends in chronic liver disease in the United States, Dr. Younossi and his colleagues drew from National Vital Statistics Data during 2007-2016. They used ICD-10 codes to select mortality data for alcoholic liver disease, chronic hepatitis B and C, iron overload, NAFLD, cirrhosis, and hepatocellular carcinoma. NAFLD cases were defined as those having an ICD-10 code for NAFLD/NASH or an ICD-10 code for “cirrhosis of unknown etiology.” Next, the researchers adjusted age-standardized death rates to the 2000 U.S. Census population and used logistic regression and propensity scores to estimate predictors of chronic liver disease-related deaths.
Dr. Younossi, who chairs the department of medicine at Inova Fairfax Medical Campus, in Falls Church, Va., and his colleagues reported findings from 838,809 chronic liver disease–related deaths during the study period. They found that the age-standardized death rate for chronic liver disease increased from 21.9/100,000 population in 2007 to 24.9/100,000 population in 2016, which translated into an annual percentage change of 1.3% for males and 2.5% for females. Chronic liver disease–related deaths increased with age and were highest among those aged 55-64 years, followed by those aged 65-74 years – an average annual percentage change of 3.4% and 3.1% in each group.
Among chronic liver disease–related deaths, the most common diagnostic etiology was NAFLD (34.7%), followed by alcoholic liver disease (28.8%) and chronic hepatitis C (21.1%). Between 2007 and 2016, death rates increased from 7.6 to 9.0 per 100,000 population for NAFLD (an average annual percentage change of 2.1%) and from 6.1 to 7.9 per 100,000 population for alcoholic liver disease (an average annual percentage change of 3.1%). “What surprised me was that, despite highly effective treatment for HCV, we still have a burden of hepatitis C in this country,” Dr. Younossi said. “It’s still the most common cause of liver disease in the U.S. But it seems like hepatitis C–related liver disease is being replaced quickly by liver disease from nonalcoholic steatohepatitis. This transition between hepatitis C as the most important cause of liver disease and liver mortality to NASH or obesity-related NASH is becoming more rapid than I expected.”
On multivariate analysis, three factors were independently associated with an increased risk of death in NAFLD: the presence of type 2 diabetes (odds ratio, 1.78), cardiovascular disease (OR, 1.07), and renal failure (OR, 1.08).
“One important message from this study is that NASH is very common in the U.S. population,” said Dr. Younossi, who is also a professor of medicine at Virginia Commonwealth University, Richmond. “These patients are underrecognized and underdiagnosed because they are asymptomatic. The second message is that there is a subtype of patients with fatty liver disease – even a subtype of NASH – that can progress to cirrhosis and its complications. We have to pay attention to this silent disease to identify patients who are at risk for progressive liver disease and try to address some of the risk issues, such as tight control of diabetes, obesity, and control of hypertension and hyperlipidemia. Short of that, right now we have very few medical treatments such as vitamin E and pioglitazone recommended for a very selected group. In contrast, there are plenty of new medications that are being developed. The first step in tackling this disease is to identify who the patients are with fatty liver disease who are at risk for bad outcomes and make sure they’re linked to care by a knowledgeable caregiver [who] understands the importance of NASH.”
Dr. Younossi acknowledged certain limitations of the study, including the fact that liver disease diagnoses were based on ICD-10 coding. He disclosed that he is a consultant for Gilead, Intercept, Novo Nordisk, BMS, AbbVie, Viking, Term Quest Diagnostics, Echosens,and Shionogi. He has also received grant/research support from Gilead, Intercept, and BMS.
Source: Hepatol. 2018;68[S1], Abstract 763.