Evaluating the renal safety of tenofovir disoproxil fumarate in hepatitis B patients without chronic kidney disease.

The nephrotoxicity of tenofovir disoproxil fumarate (TDF) in chronic hepatitis B (CHB) patients without chronic kidney disease (CKD) remains controversial. We aimed to evaluate nephrotoxicity of TDF in this population. In this hospital-based cohort study, CHB patients who received either TDF or entecavir (ETV) therapy, and did not have underlying CKD, were retrospectively recruited from January, 2008 to January, 2019. After excluding those with confounding conditions, 257 TDF-treated patients were matched through propensity scores with 514 ETV-treated patients. Cumulative incidences of, and hazard ratios (HRs) for the CKD guideline-defined renal dysfunction, were analysed. The mean decline in glomerular filtration rate was similar over 60 months (TDF vs. ETV: 10.1 ml/min/1.73 m2 , 95% confidence interval [CI]: 7.4-12.7 vs. 8.0 ml/min/1.73 m2 , 95% CI: 6.4-9.6; p = .34). The 5-year cumulative incidence of renal dysfunction was not significantly different (TDF vs. ETV: 10.4%, 95% CI: 5.6-18.0 vs. 5.8%, 95% CI: 3.6-9.0; p = .18). However, in multivariable stratified analysis, TDF was associated with an increased risk of renal dysfunction in the elderly (age ≥60 years), when compared to ETV (HR 2.86, 95% CI: 1.02-8.01; p < .05). For confirming the effect of TDF amongst the elderly, 61 TDF-treated patients were further matched with 183 ETV-treated patients, with 5-year cumulative incidence of renal dysfunction being significantly higher in TDF users (TDF vs. ETV: 34.4%, 95% CI: 17.7-59.8 vs. 15.5%, 95% CI: 9.4-25.1; p < .05). TDF use was independently related to renal dysfunction (HR 2.71, 95% CI: 1.19-6.14; p < .05). Although TDF is generally safe for CHB patients without CKD, it is best to be avoided in the elderly.