Liver biopsy is considered the "gold standard"
for assessing liver fibrosis,
but the procedure is expensive, uncomfortable, and associated with a small risk
of complications. Researchers have therefore explored various non-invasive methods
for monitoring fibrosis progression.
In a study described in the March
2008 Journal of Viral Hepatitis, Italian researchers evaluated the use
of non-invasive markers for assessing fibrosis in hepatitis
C patients with normal alanine aminotransferase (ALT) levels. ALT is a marker
of liver inflammation, but does not necessarily reflect fibrosis; some people
with chronic hepatitis C have significant liver damage despite persistently normal
ALT.
The present study included 80 hepatitis C patients with normal ALT
and 164 with elevated ALT who underwent diagnostic liver biopsies. They were also
evaluated using various non-invasive biomarker methods:
•
Fibroindex (incorporating platelet count, AST, and gamma globulin).
The
primary end-point was the detection of significant fibrosis, defined as stage
F2 or higher. Performance of non-invasive markers was expressed as specificity,
sensitivity, positive (PPV) and negative (NPV) predictive values, accuracy, and
area under the receiver operating characteristic curve (AUROC).
Results
•
All non-invasive markers for liver fibrosis demonstrated poorer performance in
patients with normal ALT compared with the elevated ALT group.
•
Overall, Fibrotest had the best performance in the normal ALT group, as indicated
by an AUROC of 0.70 and 73.5% accuracy.
•
Performance of AST-to-ALT ratio, Forns' index, and Fibroindex was poor in the
normal ALT group.
•
Forns' index and Fibroindex performed significantly worse in the normal ALT group
compared with the elevated ALT group (AUROC 0.6 vs 0.76 and 0.58 vs 0.74, respectively;
P = 0.05).
•
In patients with normal ALT, the PPV was high (> 87%) for all non-invasive
markers except for AST-to-ALT ratio.
•
However, NPV was low (< 65%), and none of the tests was able to reliably exclude
significant fibrosis.
Conclusion
In
conclusion, the investigators wrote, "performance of non-invasive markers
is significantly reduced in HCV patients with normal ALT."
"Liver
biopsy may still be needed for many of these cases to correctly stage liver fibrosis,"
they continued. "Specific non-invasive tools and possibly combination[s]
of markers should be developed and validated in this clinical setting."
3/11/08
Reference G
Sebastiani, A Vario, M Guido, and others. Performance of noninvasive markers for
liver fibrosis is reduced in chronic hepatitis C with normal transaminases. Journal
of Viral Hepatitis 15(3): 212-218. March 2008.
