The switch from TDF to TAF determines weight gain in patients on rilpivirine-based regimen

OBJECTIVE: To investigate whether the switch from tenofovir disoproxil fumarate/emtricitabine/rilpivirine (TDF/FTC/RPV) to tenofovir alafenamide (TAF)/FTC/RPV is associated with weight gain in people living with HIV (PLWHIV). DESIGN: Retrospective single-centre study. METHODS: All PLWHIV on TDF/FTC/RPV who switched to TAF/FTC/RPV from January 2017 to December 2018 were considered if they had at least two weight measures in the year before and two after the switch. The weight trend across the study was evaluated by a generalized linear model for repeated measures, with pair comparison performed by Bonferroni adjustment. RESULTS: Two hundred and fifty-two patients on TDF/FTC/RPV were included, 65% men, mean age 51.2 years (±9.6), history of 18 (±18.2) years of HIV infection and CD4 T-cell count of 744 (±329) cells/μl. All had HIV-RNA <50 copies/ml. Twelve months before the switch, baseline weight was 73.8 (±14.3) kg, and remained stable to 73.8 (±14.3) kg in the following 6 months. A weight increase was noticed 3 and 6 months after the switch, to 77.7 (±42.3) and 75.5 (±14.5) kg, respectively (P < 0.0001). A significant weight change exactly within the timeframe of the switch (between 6 months before and 3 months after) was found in women, patients with higher BMI (>25 kg/m), lower CD4 T-cell count (≤500 cells/μl) and history of previous drug abuse. The frequency of BMI greater than 25 kg/m rose from 122/252 patients (48.4%), to 133/252 (52.8%) (P < 0.0001). CONCLUSION: TAF appears to have an impact on weight gain, similarly to what observed in naïve patients, also in experienced PLWHIV with good virologic control.