Liver Stiffness Measurement (FibroScan) More Useful for Assessing Fibrosis in Patients with HCV Compared with HBV  

Liver biopsy is considered the “gold standard” for assessing liver fibrosis progression, but the procedure is uncomfortable, expensive, and associated with a small risk of complications such as bleeding.

Therefore, researchers have explored several non-invasive methods for estimating liver fibrosis. One of these, transient elastometry (FibroScan) estimates the extent of fibrosis by measuring liver “stiffness.”

To date, most studies of transient elastometry have been done in patients with chronic hepatitis C. In a study presented at the recent 58th Annual Meeting of the American Association for the Study of Liver Diseases in Boston (November 2-6, 2007), Korean researchers sought to determine whether the method works as well in people with chronic hepatitis B.

The investigators enrolled 64 patients with chronic hepatitis B and 27 with chronic hepatitis C who underwent liver biopsy. About two-thirds were men, and the median age was 40 years (range 14-68 years). Liver biopsies and transient elastometry were performed on the same day. Interpretation of fibrosis scores was done by an experienced pathologist using the Metavir system (stage F0-F4).

Results

·    The distribution of fibrosis scores based on liver biopsy were as follows:

o        absent to mild (F0-F1): 27 patients;

o        significant (F2): 27 patients;

o        severe (F3): 26 patients;

o        cirrhosis (F4): 11 patients.

·    The median serum ALT level was 58 IU/L and the median bilirubin level was 0.8 mg/dL.

·    Liver stiffness measurement was well correlated with fibrosis score for all patients (Kendall’s correlation coefficient: 0.617; P<0.001).

·    The areas under the receiver operator characteristics (ROC) curve were 0.901 for patients with significant fibrosis (F ≥2), 0.899 for patients with severe fibrosis (F ≥3), and 0.883 for patients with cirrhosis (F = 4).

·    Optimal transient elastometry cutoff values were 7.15 kPa for F ≥2, 11.9 kPa for F ≥3, and 13.85 kPa for F4.

·    Liver stiffness measurement was better correlated with fibrosis scores in patients with chronic hepatitis C than in those with chronic hepatitis B (0.773 vs 0.557; P < 0.001).

·    The areas under the ROC curve were larger for patients with chronic hepatitis C (0.944, 0.982, and 0.958 for F ≥2, F ≥3, and F4) than for chronic hepatitis B (0.881, 0.863, and 0.850, respectively).

·    The optimal cutoff values for F ≥2 and F ≥3 were similar for patients with chronic hepatitis C (7.05 and 11.4 kPa) and chronic hepatitis B (7.15 and 10.75 kPa).

·    However, sensitivity and specificity were superior in patients with chronic hepatitis C.

Conclusion

“Liver stiffness measurement is a simple, safe, and effective method for assessing liver fibrosis in patients with chronic viral hepatitis,” the investigators concluded.

However, they added, “The efficacy of liver stiffness measurement for the assessment of liver fibrosis was superior in patients with chronic hepatitis C than in patients with chronic hepatitis B.”

12/04/07

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