335. Antiretroviral Therapy Anchor-based Trends in Body Mass Index following Treatment Initiation among Military Personnel with HIV

Background Weight gain and obesity in people living with HIV have been associated with increased risk for non-AIDS-related comorbidities, and integrase strand transfer inhibitor (INSTI)-based regimens may lead to comparatively more weight gain than other regimens. We evaluated body mass index (BMI) following antiretroviral therapy (ART) initiation among participants in the US Military HIV Natural History Study (NHS). Methods Of 961 NHS participants started on initial ART between 2006–2017, 496 men who had available baseline BMI data and were virally suppressed (< 200 c/mL) at 1 and 2 years of follow-up were included (Tables 1 and 2). ART was categorized by anchor class to include INSTIs, non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs). Linear growth-curve modeling was used to predict BMI changes from ART initiation through 2 years of follow-up in participants stratified by baseline BMI (< 25 vs. ≥25 kg/m2) at ART start and anchor drug class. Demographic and HIV-related characteristics were analyzed as independent variables. Results Overall, the predicted BMI increased over 2 years regardless of baseline BMI (Table 3). There was a trend toward decreased BMI on ART for those with BMI ≥ 25 treated with a non-INSTI regimen (−0.63, P = 0.079). In participants with BMI 100,000 c/mL) started on PI regimens (−1.61, P = 0.013). For those with BMI ≥ 25, only INSTI- and PI-based regimens were significantly associated with increased BMI (INSTI 0.54, P = 0.000; NNRTI 0.11, P = 0.174; PI 0.39, P = 0.006). Observed BMI increases for INSTI and PI regimens were also associated with increased time from HIV diagnosis to ART initiation (INSTI 0.35, P = 0.003; PI 0.44, P = 0.037). African Americans with BMI ≥ 25 on INSTIs had the greatest predicted gains in BMI (1.84, P = 0.007). Conclusion In our cohort of young military members with HIV infection, those with baseline BMI < 25 experienced BMI gains across all ART classes. Among those with baseline BMI ≥ 25, African Americans on INSTI regimens had the greatest BMI gains. Further studies are needed to determine whether NNRTI regimens should be considered in certain individuals at risk for INSTI-associated weight gain. Disclosures All authors: No reported disclosures.