Liver disease may be more deadly than previously thought.
The Centers for Disease Control and Prevention ranks mortality related to chronic liver disease and cirrhosis as the 12th most common cause of death in U.S. adults, but research recently presented at the American Association for the Study of Liver Diseases suggests the actual ranking should be higher. The investigators conclude the mortality impact of liver disease in the U.S. is underestimated.
Deaths associated with other descriptors of liver disease (e.g., portal hypertension, viral hepatitis, and hepatobiliary cancer) are not included in the CDC?s calculations, says W. Ray Kim, MD, a gastroenterologist with Mayo Clinic and one of the study?s author.
Using a modified definition that includes diseases such as viral hepatitis, liver cancer, and obesity-related fatty liver disease, he and his colleagues determined that liver-related mortality is as high as fourth for some age groups, and eighth overall.
They arrived at this conclusion by analyzing mortality data using more comprehensive criteria. The research team examined data from the CDC's national death registry for deaths among adults during 1979-2006 and compared their results to statistics from the Rochester Epidemiology Project, a long-term, collaborative medical records project among healthcare providers in Olmsted County, Minn. (There was a good correlation between the national statistics and the Olmsted County mortality data, says Kim.)
Using the most comprehensive definition, the researchers concluded that liver disease was the eighth leading cause of death in the U.S. in 2006: 27,543 deaths using the CDC definition, 9,257 with the expanded liver diagnosis, 7,214 with viral hepatitis, and 16,492 with hepatobiliary cancer. The updated death rate was 121% higher than the CDC estimate (24.6 vs. 11.2).
There was at least one surprise, he tells HealthLeaders Media: "We also noted that the time trend for liver disease death did not show an increase as we expected from the rise in the burden of hepatitis C."
The impetus for the study was simple: Liver disease is underdiagnosed, Kim tells Health Leaders Media. "Liver disease is an important cause of morbidity and mortality in the U.S.— more than we have recognized in the past— and as physicians, we need to be aware of that."
Many people in the U.S. have hepatitis C, and as they grow older, they experience complications. Moreover, related to the rising obesity rates, a large number of individuals have fatty liver disease. Some go on to develop end-stage liver disease, cirrhosis, or liver cancer, he explained.
Analyzing the mortality data using the more comprehensive criteria, he and his colleagues were able to discover the true impact of liver disease on the population.
The implications for clinicians are clear, says Kim: Obese people and those with hepatitis C need to be watched especially closely for liver disease as part of their overall medical management program. "Many liver disease patients are asymptomatic until they have really advanced disease."