Utility of liver stiffness measurement by fibroscan in assessment of fibrosis in patients with chronic hepatitis B

Abstract

Background and Aim: Assessment of liver fibrosis is an important determinant for staging of disease, prognosis as well as therapeutic decision making in patients with chronic hepatitis B(CHB). Liver biopsy, although is gold standard, has certain limitations. Fibroscan is simple to perform, non-invasive, has good patient acceptance and reproducible. However, role of fibroscan in assessing fibrosis in CHB has remained controversial. Methods: Fibroscan and liver biopsy were performed in 382 consecutive patients of CHB. Biopsies were reviewed by pathologist blinded to the fibroscan value. Discriminant values of liver stiffness measurement (LSM) were calculated from receiver operating characteristic (ROC) curves to reasonably exclude and predict significant fibrosis, so as to avoid liver biopsy. The factors affecting LSM value were also assessed. Results: Twenty five patients were excluded because of inadequate biopsy or invalid fibroscan. Three hundred fifty seven patients were finally included(mean age 30.1±9.7 years, male:female 17:3).There was significant correlation between LSM and histological fibrosis(r=0.5, P< 0.001). The area under ROC curve of LSM for significant fibrosis (F0-1 vs F2-4), bridging fibrosis (F0-2 vs F3-4) and liver cirrhosis(F0-3 vs F4) was 0.84(95% CI: 0.78-0.89), 0.94(95% CI: 0.89-0.99) and 0.93(95% CI: 0.00-1.00) respectively. Cutoff of 6.0 KPa, could exclude presence of significant (F<2) and bridging fibrosis(F <3) with a negative predictive value (NPV) of 92.4% and 99.5% respectively. Cutoff of 8 Kpa, 9 Kpa, and 11 Kpa could detect significant fibrosis (F<2), bridging fibrosis(F<3) and cirrhosis(F=4) with specificity of 95%. Cutoffs of 9 Kpa and 12 Kpa had a positive predictive value (PPV) of 85% and 100% in predicting significant and bridging fibrosis respectively. Thus LSM values < 6 Kpa and < 9 Kpa matched with histological fibrosis in 227/250(91%) patients. On multivariate analysis, histological fibrosis was the only independent determinant of increased liver stiffness. Conclusions: Fibroscan could avoid liver biopsy in 70%(250/357) patients with a diagnostic accuracy of >90%.