A
study of non-invasive alternatives to liver
biopsy for assessing fibrosis
has concluded that a series of simple blood tests can accurately diagnose the
condition, according to a report in the February 2007 issue of Hepatology.
Fibrosis, the
formation of fibrous scar tissue in the liver, typically indicates progressive
damage, and can progress to liver cirrhosis.
Determining the stage of fibrosis is important for people with chronic hepatitis
C since it can help guide decisions about treatment. While liver biopsy is considered
the "gold standard" for assessing liver
disease, it is uncomfortable and expensive, prompting researchers to develop
non-invasive methods.
Japanese
researchers conducted a study of 402 chronic hepatitis C patients who underwent
liver biopsy between April 1994 and March 2004; those with pre-existing cirrhosis
were excluded. Blood samples were collected within 3 days of the biopsies, and
the investigators identified routinely measured markers associated with fibrosis
progression. The resulting index was then test in a group of 30 patients who underwent
a second biopsy more than 1 year after treatment with interferon-based therapy.
Results
•
Based on the original 402 subjects, the researchers identified 3 markers as independent
predictors of fibrosis, collectively dubbed "FibroIndex":
•
The areas under the
receiver operating characteristic curves (AUROCs) of FibroIndex for predicting
significant fibrosis were 0.83 and 0.82.
•
FibroIndex was more
accurate in predicting significant or severe fibrosis than the Forns index or
the AST-to-platelet ratio index (APRI).
•
Using the best cutoff
values to identify the absence or presence of significant fibrosis, 101 patients
(35%) could have avoided liver biopsy. •
For the 30 treated
patients, changes in FibroIndex directly correlated with changes in fibrosis as
determined by biopsy, while the Forns and APRI indices did not show this association. •
FibroIndex scores decreased
significantly in 14 patients whose fibrosis stage improved, but increased significantly
in 5 patients whose fibrosis stage deteriorated.
•
FibroIndex was also
accurate in a subset of patients with normal levels of alanine aminotransferase
(ALT), a third of whom had significant fibrosis.
Conclusion
The
researchers concluded that, "The FibroIndex is a simple and reliable index
for predicting significant fibrosis in [patients with] chronic hepatitis C and
could also be used as a surrogate marker during anti-fibrotic treatment for chronic
hepatitis C."
The
authors noted that platelet count, AST, and gamma globulin are easily determined
using routine blood tests available in most hospitals and laboratories, making
it a widely accessible tool for determining fibrosis.
"The
utilization of FibroIndex should decrease the number of liver biopsies necessary
during follow-up of patients with hepatitis C and could safely provide longitudinal
data on the progression of liver fibrosis," they added.
Accurate
non-invasive fibrosis tests could be especially important for HIV positive individuals
coinfected with HCV, who tend to experience more rapid liver disease progression.
02/06/07
References
M Koda, Y Matunaga, M Kawakami, and others. FibroIndex, a Practical
Index for Predicting Significant Fibrosis in Patients with Chronic Hepatitis C.
Hepatology 45(2): 297-306. February 2007.
