Changes in renal function after switching from TDF to TAF in HIV-infected individuals: a prospective cohort study. Journal of Infectious Disease
Surial et al. aimed to estimate the impact of replacing tenofovir disoproxil fumarate (TDF) by tenofovir alafenamide (TAF) on estimated glomerular filtration rate (eGFR) and proteinuria, and to assess whether differences exist among patients with renal dysfunction and other comorbidities.
In all participants from the Swiss HIV Cohort Study who switched from TDF to TAF-containing antiretroviral regimen or continued TDF, the authors estimated changes in eGFR and urine protein-to-creatinine ratio (UPCR) after 18 months.
Of 3’520 participants (26.6% women, median age 50 years), 2404 (68.5%) switched to TAF. Overall, 1664 (47.3%) had an eGFR <90 mL/min and 1087 (30.9%) an UPCR ≥15 mg/mmol. In patients with baseline eGFR ≥90 mL/min, eGFR decreased with the use of TDF and TAF (−1.7 mL/min). Switching to TAF was associated with increases in eGFR of 1.5 mL/min (95% confidence interval [CI], .5–2.5) if the baseline eGFR was 60–89 mL/min, and 4.1 mL/min (95% CI, 1.6–6.6) if <60 mL/min. In contrast, eGFR decreased by 5.8 mL/min (95% CI, 2.3–9.3) with continued use of TDF in individuals with baseline eGFR <60 mL/min. UPCR decreased after replacing TDF by TAF, independent of baseline eGFR.
In conclusion, these findings suggest that switching from TDF to TAF or to another TDF-free backbone should be considered in individuals with established renal dysfunction. In the absence of other risk factors for TDF-associated toxicity, continuing TDF in individuals with a normal renal function seems reasonable, and has the potential to reduce HIV-related costs due to the availability of generic formulations of TDF. Additionally, because TAF seems to be associated with other adverse events such as increases in cholesterol levels and weight gain, longer term follow-up from observational cohort studies is needed to confirm the safety and efficacy of TAF in individuals with comorbidities.