Background: Tenofovir alafenamide (TAF), characterized by its better renal safety profile than tenofovir disoproxil fumarate (TDF), became available in Switzerland in October 2016. We compared the impact of switching from TDF to TAF on estimated glomerular filtration rate (eGFR).
Methods: We included all participants of the Swiss HIV Cohort Study on TDF-containing antiretroviral therapy with follow-up after January 2016 who remained on TDF until the end of the observation period (October 2018), or switched to TAF. Baseline was defined as (1) switching date for patients on TAF, (2) October 1st 2016 for patients remaining on TDF, or (3) registration date for patients remaining on TDF and registered after October 1st 2016. We calculated eGFR with the CKD-EPI formula, and used multivariable linear mixed-effect models to explore the association between receiving TAF and eGFR over time.
Results: Of 3''430 individuals included, 2''499 (72.9%) were male and the median age was 49 years (IQR 42-56). At baseline, 1''823 individuals (53.1%) had an eGFR ≥90 ml/min, 1''433 (41.8%) a value of 60-89 ml/min, and 174 (5.1%) had an eGFR < 60 ml/min. The median follow-up time was 15.3 months (IQR 13.4─16.6) for 1''575 individuals who remained on TDF and 11.4 months (8.8─13.6) for 1''855 who switched to TAF. Adjusted eGFR trajectories were similar in both groups if baseline eGFR was ≥90 ml/min (predicted difference in eGFR after 18 months: 0.3 ml/min, 95% confidence interval [CI] -1.5─2.0 ml/min) or 60-89 ml/min (predicted difference: 1.4 ml/min, 95% CI -0.4─3.2 ml/min). In contrast, difference in eGFR at 18 months was 9.6 ml/min (95% CI 5.1─14.0 ml/min) between individuals on TAF compared to those remaining on TDF if baseline eGFR was < 60 ml/min. (Figure).
Conclusions: TAF was associated with an increase in eGFR over time compared to TDF in patients with moderate to severe impairment of renal function.

Comparisons of predicted eGFR trajectories over time between TDF (dashed) and TAF (solid).
[Comparisons of predicted eGFR trajectories over time between TDF (dashed) and TAF (solid). ]