Mild-to-moderate elevation of alanine aminotransferase increases liver stiffness measurement by transient elastography in patients with chronic hepatitis B.

OBJECTIVES: Liver stiffness measurement has been shown to be increased in severe acute flares of hepatitis. Whether lesser degree of hepatitis can also increase liver stiffness is not known. The present study aimed to investigate the effect of mild-to-moderate elevations of alanine aminotransferase (ALT) on liver stiffness in chronic hepatitis B.
METHODS: Fifty-eight patients with chronic hepatitis B with ALT levels from 1 to 10 × upper limit of normal were recruited. Liver stiffness measurements were performed at the time of ALT elevation, and liver stiffness measurement was repeated once normalization of ALT occurred after antiviral therapy. Liver biopsies were performed in 38 patients.
RESULTS: All 58 patients achieved normalization of ALT after antiviral therapy, with a median time of 3 months between the first and second liver stiffness measurement. There was a significantly lower median liver stiffness measurement after commencement of antiviral therapy, with the normalization of ALT levels compared with pre-treatment levels (6.4 vs. 7.9 kPa, respectively; P<0.001). The area under the receiver operator characteristic curve for diagnosing F2 fibrosis in elevated ALT was 0.68, compared with 0.73 after ALT normalization. Twelve (32%) patients would have been misclassified as having cirrhosis using liver stiffness measurements taken at the time of ALT elevation, compared with 16% after normalization of ALT.
CONCLUSIONS: Even mild-to-moderate elevation in ALT levels may increase liver stiffness independent of underlying liver fibrosis. Higher levels of ALT were associated with higher discrepancies in liver stiffness. Therefore, the timing of liver stiffness measurement is important.