Reuters Health Information (2006-08-31): Hepatitis B viral load associated with subsequent liver cancer mortality
Hepatitis B viral load associated with subsequent liver cancer mortality
Last Updated: 2006-08-31 14:55:05 -0400 (Reuters Health)
NEW YORK (Reuters Health) - A high hepatitis B viral load is a prognostic factor for death from hepatocellular carcinoma (HCC) and chronic liver disease, investigators report in the August issue of the American Journal of Gastroenterology.
Dr. Alison A. Evans of the Fox Chase Cancer Center in Philadelphia, Pennsylvania, and associates in China studied data on 2763 Chinese patients who were hepatitis B surface antigen-positive and had blood samples stored when they were recruited in 1992-1993.
During follow-up through 2003 there were 447 deaths: 231 due to HCC, 85 attributed to chronic liver disease, and 131 to non-liver causes.
There was a significant increase in mortality across three ranges of viral load measured in the original samples -- i.e., undetectable viral load, low titers (below 100,000 copies/ml) and high titers (100,000 copies/ml or higher).
Compared with patients with undetectable virus, the relative risk for HCC mortality was 1.7 for patients with low HBV titers and 11.2 for patients with high HBV titers.
For chronic liver disease mortality, the relative risk was 1.5 for those with low viral titers and 15.2 for patients with high HBV titers. Among those with high viral titers, the relative risk did not increase during 11 years of follow-up.
"Viral load is already used as a clinical marker for monitoring the progress of chronic infection and to determine whether anti-viral therapies are working," Dr. Evans commented in correspondence with Reuters Health. "What our study shows is that this marker is a very good predictor of very long-term risk of dying of HCC or CLD, which bolsters its use as a clinical marker for more than just short-term prognosis."
The study also analyzed the health status of the survivors, who were presumably relatively healthy, in relation to initial viral load. The odds ratio for severe liver disease was 1.3 with low viral loads and 2.7 with high viral loads, compared with undetectable viral DNA.
"Even among relatively healthy HBV-infected people, viral load is an important indicator of just how sick they might become in the long-term future," Dr. Evans said.
"Because the relative risk doesn't change over time, it suggests that viral load is a very good long term marker of risk of serious complications of HBV infection," Dr. Evans commented.
"It frankly surprised us that just one measurement of viral load, as much as a decade before death, was such a powerful predictor," she continued. "We don't yet know what the implications are for someone with a viral load that is changing over time naturally. For people whose viral load is reduced with anti-viral drugs, however, it's pretty clear that their liver function improves and disease progression slows."
In addition to the clinical implications for people already being followed medically for HBV infection, "the study supports public health efforts to identify HBV carriers as early as possible, particularly in high-risk populations," Dr. Evans concluded. "And it underscores the need for continued development of anti-viral drugs that can effectively treat chronic HBV infection."
Am J Gastroenterol 2006;101:1797-1803.