Switching from tenofovir disoproxil fumarate to tenofovir alafenamide or dual therapy-based regimens in HIV-infected individuals with viral load ≤50 copies/mL: does estimated glomerular filtration rate matter?

Our aim was to evaluate the association between recent eGFR values and risk of switching from TDF to TAF or dual therapy (DT) in real life. HIV-positive patients achieving HIV-RNA ≤50 copies/mL for the first time after starting a TDF-based regimen were included. Kaplan-Meier (KM) curves and Cox regression models were used to estimate the time from TDF to switch to TAF or DT. 1486 participants were included: median (IQR) age 36 (30-42) years; baseline CKD-EPI eGFR 99.92 (86.47-111.4) mL/min/1.73m. We observed a consistently higher proportion of people with HIV-RNA ≤50 copies/mL who switched from TDF to TAF rather than to DT. By competing risk analysis, at 2 years from baseline, the probability of switching was 3.5% (95% CI 2.6-4.7%) to DT and 46.7% (42.8-48.5%) to TAF. A significantly higher probability of switching to TAF was found for patients receiving INSTI at baseline versus NNRTIs and PI/b [KM, 65.6% (61.7-69.4%) vs. 4.0% (1.8-6.1%) and 59.9% (52.7-67.2%), respectively; P < 0.0001]. eGFR <60 mL/min/1.73m both as time-fixed covariate at baseline or as current value was associated with a higher risk of switching to DT [aHR 6.68 (2.69-16.60) and 8.18 (3.54-18.90); P < 0.001] but not to TAF-based cART [aHR 0.94 (0.39-2.31), P = 0.897; and 1.19 (0.60-2.38), P = 0.617]. Counter to our original hypothesis, current eGFR is used by clinicians to guide switches to DT but does not appear to be a key determinant for switching to TAF.