Non-invasive
FibroTest and FibroScan Predict Liver Cirrhosis Better than Earlier Stages of
Fibrosis in Hepatitis C Patients
While
liver biopsy is considered the "gold standard" for assessing liver
fibrosis, the procedure is expensive and is associated with a small
risk of complications including excessive bleeding. But accurate
assessment of liver damage is needed to guide decisions about viral
hepatitis treatment. Therefore, researchers have developed a variety of non-invasive
methods to reduce the need for biopsies.
As reported in the November 2007 American Journal of Gastroenterology,
researchers performed a systematic review of prior studies of 2 of these methods,
FibroTest and FibroScan, in patients with hepatitis C. FibroTest
(BioPredictive) combines the biomarkers
alpha2-macroglobulin, haptoglobin, apolipoprotein A1, total bilirubin, and GGT,
adjusted for a patient’s age and sex. FibroScan uses a technique called transient
elastometry to measure liver stiffness.
Studies
comparing FibroTest
or FibroScan
versus biopsy in hepatitis C patients were identified
through an electronic search. Random effects meta-analyses and areas under receiver operating characteristics
curves (AUROCs) were examined to characterize test accuracy for significant fibrosis
(stages F2-F4) and cirrhosis.
Results
•
12 relevant
studies were identified:
•
9
for FibroTest (1679 total subjects);
•
4
for FibroScan (546 total subjects).
•
In heterogeneous analyses
for significant fibrosis, the AUROCs for FibroTest and FibroScan were 0.81 and
0.83, respectively.
•
At a threshold of approximately
0.60, the sensitivity of FibroTest was 47% and the specificity was 90%.
•
Using a threshold of approximately
8 kPa, the sensitivity of FibroScan was 64% and the specificity was 87%.
•
Methodological quality, size
of liver biopsy specimens, and inclusion of special populations did not explain
the observed heterogeneity.
•
However, the diagnostic accuracy
of both measures was associated with the prevalence of significant fibrosis and
cirrhosis in the study populations.
•
For cirrhosis, the summary
AUROCs were 0.90 for FibroTest and 0.95 for FibroScan.
Conclusion
"FibroTest
and FibroScan have excellent utility for the identification of HCV-related cirrhosis,
but lesser accuracy for earlier stages," the study authors concluded. "Refinements
are necessary before these tests can replace liver biopsy."
This
review adds to the evidence that non-invasive methods tend to perform well at
estimating extreme degree of liver fibrosis (none versus severe fibrosis or cirrhosis),
but do less well at predicting intermediate stages.
Liver Unit, Division
of Gastroenterology, Department of Medicine, University of Calgary, Calgary, Alberta,
Canada.
12/11/07
Reference AA
Shaheen, AF Wan, RP Myers. FibroTest and FibroScan for the Prediction of Hepatitis
C-Related Fibrosis: A Systematic Review of Diagnostic Test Accuracy. American
Journal of Gastroenterology 102(11): 2589-2600. November 2007.
Studies
