Background: Tenofovir alafenamide (TAF) has good viral suppression efficacy and less adverse effect than tenofovir disoproxil fumarate (TDF). Real-world studies on the antiviral efficacy and safety of switching from TDF to TAF in patients with chronic hepatitis B (CHB) are limited. Methods: This retrospective study included 167 nucleos(t)ide analogue (NA)-naive patients with CHB. All the patients received TDF at least 12 months before switching and TAF at least 12 months after switching at a single medical center. The Friedman test with Dunn-Bonferroni post hoc tests and repeated-measures analysis of variance was used to analyze the effect of complete viral suppression, alanine aminotransferase (ALT) level normalization, renal function changes, body weight, and body mass index in the periods before and after switching. Results: The mean age and TDF treatment duration were 52 +/- 11 years and 2.8 years (interquartile range, 1.51-5.15 years), respectively. The complete viral suppression rate was similar between the time of switching and 48 weeks after switching to TAF (77.8% vs 76%, P = 1.000). The percentage of alanine aminotransferase (ALT) normalization increased from 26.3% at TDF start to 81.4% (P < 0.001) at time of switching and 89.2% at 48 weeks after switching to TAF (P = 0.428). The median estimated glomerular filtration rate decreased from 100.09 mL/min/1.73 m(2) at TDF start to 91.97 mL/min/1.73 m(2) (P < 0.001) at the time of switching and stabilized at 48 weeks after switching to TAF (93.47 mL/min/1.73m(2), P = 1.000). The body weight decreased from 69.2 +/- 12.2 kg at TDF start to 67.4 +/- 12.1 kg (P < 0.001) at the time of switching to TAF and returned to 68.7 +/- 12.7 kg (P < 0.001) 48 weeks thereafter. The body mass index (BMI) decreased from 25 +/- 3.3 kg/m(2) at TDF start to 24.5 +/- 3.3 kg/m(2) (P = 0.002) at the time of switching to TAF and returned to 25.1 +/- 3.6 kg/m(2) (P < 0.001) 48 weeks thereafter. Conclusions: Our study showed that switching to TAF from TDF had good antiviral effectiveness and stabilized renal function. The body weight and BMI decreased during TDF therapy and regained after switching to TAF.
