1041. Tenofovir alafenamide associated weight change in persons living with HIV

BACKGROUND: Persons living with human immunodeficiency virus (PLWH) have a higher incidence of developing obesity, diabetes, and cardiovascular disease. TAF, a newer formulation of tenofovir, has favorable effects on renal function and bone mineral density compared to TDF. However, recent evidence suggests TAF may have a higher propensity for weight gain over TDF. The purpose of this study is to evaluate weight change in patient switched from TDF to TAF, keeping constant the other components of their antiretroviral therapy. METHODS: This retrospective observational cohort study evaluated adult PLWH who were followed for 12 months pre and post TDF to TAF therapy switch holding all other ART constant. Patients were excluded if not on TDF or TAF therapy for a minimum of 12 months, if there were additional changes to their ART, or if there was inadequate documentation of weight defined as less than 2 weight records pre and post TAF switch. Data collected included height, weight, HIV RNA, CD4 count, and presence of any current opportunistic infections or chronic comorbid conditions. The primary endpoint was change in weight after TAF switch. All variables were evaluated using linear mixed effect models over time. RESULTS: 466 patient charts were reviewed and 55 patients met study criteria and were included in the analysis. The median age (SD) of patients included was 45.9 (12.6) years with most patients being male (67%) and black (73%). Patients had an HIV diagnoses for a mean (SD) of 10 (6.6) years with a mean (SD) CD4 count of 544 (246.8). Full baseline characteristics are recorded in Table 1. Notably, most patients had either an INSTI or PI in their baseline ART regimen (Table 1). The estimated overall marginal mean weight gain was 1.91 kg (95% CI 0.25-3.57, p=0.024). The estimated overall gain in BMI was 0.63 kg/m2 (95% CI 0.08-1.18). Significant predictors of weight gain included female gender (3.09, 95% CI 0.54 – 5.65) and use of both integrase and protease inhibitors at baseline (6.97 kg, 95% CI 3.02 – 10.92). CONCLUSION: In a predominantly black, male population, there was a statistically significant change in weight after a TAF switch. As this is the only data highlighting weight changes following tenofovir formulation change, more data is needed to elucidate the extent of weight-gain in patients on TAF-based regimens. DISCLOSURES: All Authors: No reported disclosures