Long-term effects of entecavir and tenofovir treatment on the fibrotic burden in patients with chronic hepatitis B

Background and Aim: Antiviral therapy (AVT) induces fibrosis regression in patients with chronic hepatitis B. We investigated long-term effects of entecavir (ETV) versus tenofovir (TDF) on fibrotic burden. Methods: Treatment-naïve chronic hepatitis B patients who had begun ETV or TDF were recruited from four tertiary hospitals. The aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis index based on four factors (FIB-4) were used to determine fibrotic burden. Results: In the entire population (n = 3277), although patients treated with ETV had higher baseline APRI (1.71 vs 1.07, P < 0.001) and FIB-4 (3.60 vs 2.80, P < 0.001) than those treated with TDF, significant fibrosis regression was identified during 6 years of AVT in both ETV (APRI, mean 1.71 → 0.48, P < 0.001; FIB-4, mean 3.60 → 2.21, P < 0.001) and TDF groups (APRI, mean 1.07 → 0.43, P < 0.001; FIB-4, mean 2.80 → 2.19, P < 0.001). In patients without cirrhosis (n = 2366), baseline APRI was significantly higher in ETV group than in TDF group (1.72 vs 0.97, P < 0.001); however, they became similar after 6 months. Similarly, baseline FIB-4 was significantly higher in ETV group than in TDF group (3.25 vs 2.35, P < 0.001), but became similar from 4 to 6 years. In patients with cirrhosis (n = 911), baseline APRI (1.70 vs 1.34, P < 0.001) and FIB-4 (4.62 vs 3.91, P = 0.005) were higher in ETV group than in TDF, however, both parameters became statistically similar from 6 months to 6 years. Conclusion: Significant regression of APRI and FIB-4 was observed during long-term ETV and TDF treatment. Despite higher baseline fibrotic burden in ETV group, fibrotic burden between the groups eventually converged through significant fibrosis regression after 1 to 4 years of AVT.