FACTORS OF IMPROVEMENT OF LIVER STIFFNESS DURING ANTIVIRAL TREATMENT IN CHRONIC HEPATITIS B PATIENTS

초록

Background: Liver stiffness measured by transient elastography is well correlated with the degree of liver fibrosis. However,liver stiffness can be overestimated in the presence of varying degree of necroinflammation. Herein, we evaluated the factors associated with the improvement of liver stiffness 12 months after initiating antiviral agent for the treatment of chronic hepatitis B. Methods: Three hundred thirteen cases of liver stiffness measurement data of chronic hepatitis B patients at Korea University Ansan Hospital were reviewed from March, 2008 to March, 2011. Among those patients, 95 patients underwent transient elastography on the day of liver biopsy right before the initiation of antiviral agent. Thereafter, while on antiviral treatment, liver stiffness measurement (LSM) were repeated serially and 54 patients had liver stiffness measurement data followed up at 12 months after antiviral treatment. Primary endpoints were the presence of response in liver stiffness at 12 months, which was defined as either decrease of liver stiffness more than 10.0 kPa (corresponding to 1 standard deviation from the pretreatment mean value) or the reduction of absolute value of liver stiffness below 7.5 kPa. Liver histopathologic findings were assessed by Batts-Ludwig score. Results: The value of liver stiffness at baseline and at 12 months were 14.3±10.2 kPa [range 4.8-48.8, n=54] and 7.6±4.5 kPa [range 3.5-27.0, n=54], respectively. When baseline characteristics were compared according to the existence of the response in LSM, baseline value of LSM were significantly different between the two groups with or without response at 12 months (19.6±10.6 kPa vs 12.0±9.7, n=42 vs n=12, respectively, p=0.011) along with the baseline staging score of fibrosis (p<0.001). Rates of virologic response, serologic response, and the rates of normal ALT at 6, and 12 months were not different between the two groups according to the existence of response in liver stiffness. By multivariate analysis, the prognostic factors of LSM response at 12 months were staging score of fibrosis (OR= 0.096,p=0.018) and serum ALT (OR=1.046, p=0.018). Conclusions: LSM improvement is primarily affected by baseline fibrosis staging, and baseline serum ALT level also significantly influences on the changes of LSM during treatment.