Renal safety and biochemical changes for 2 years after switching to tenofovir alafenamide from long-term other nucleotide analog treatment in patients with chronic hepatitis B

Background Long-term use of nucleotide analogs such as adefovir (ADV) or tenofovir disoproxil fumarate (TDF) may cause renal impairment. Tenofovir alafenamide (TAF) has less systemic exposure than TDF did. The aims were to examine longitudinal changes in renal function and biochemical parameters for 2 years after switching from long-term ADV and TDF to TAF, and to explore factors associated with improved renal function after TAF in patients with chronic hepatitis B. Methods The prospective observational cohort study included 306 patients with chronic hepatitis B who underwent switching from long-term TDF or ADV to TAF. The primary outcome was the changes in estimated glomerular filtration rate (eGFR) after TAF. Results Among 306 patients, 190 (65.3%) and 106 (34.7%) had chronic kidney disease (CKD) stages 1-2 and 3a-4 at baseline. In patients with CKD stages 3a-4, the mean eGFR significantly increased until week 12 and plateaued from week 12 to year 2 (adjusted slope using linear mixed effect models: +9.01 ml/min/1.73 m(2)/year until week 12; p < 0.001). In contrast, the mean eGFR plateaued from baseline to year 2 in the CKD stages 1-2 subgroup. Multivariate logistic regression showed that baseline CKD stage >= 3a, steeper decline in eGFR 1 year before TAF, and shorter duration of any nucleotide analog use was significantly associated with >= 10% improvement in eGFR in year 1. Conclusions Switching from TDF or ADV to TAF resulted in favorable renal safety for 2 years. In CKD stage 3a-4 subgroup, eGFR after TAF was recovered in the first 12 weeks and subsequently stabilized.