Risk Factors for Weight Gain Following Switch to Integrase Inhibitor-Based Antiretroviral Therapy.

BACKGROUND: Treatment initiation with integrase strand transfer inhibitors (INSTIs) has been associated with excess weight gain. Whether similar gains are seen after switch to INSTI among virologically suppressed persons is less clear. We assessed pre/post-INSTI weight changes from AIDS Clinical Trials Group participants (A5001 and A5322). METHODS: Participants who were in follow-up from 1997-2017 and switched to INSTI-based antiretroviral regimens were included. Piecewise linear mixed effects models adjusting for age, sex, race/ethnicity, baseline BMI, nadir and current CD4+ T cell count, smoking, diabetes and follow-up time with suppressed HIV-1 RNA examined weight and waist circumference change before and after first switch to INSTI. Linear spline models with a single knot at time of switch accounted for non-linear trends. RESULTS: The 972 who switched to INSTI were 81% male and 50% non-white with a median age at switch 50 years, CD4+ T cell count 512 cells/muL and BMI 26.4 kg/m2. Restricting to persons with suppressed HIV-1 RNA at switch (n=691), women, blacks and persons age >/=60 experienced greater weight gain in the 2 years after versus before switch. In adjusted models, white or black race, age >/=60 and BMI >/=30 kg/m2 at switch were associated with greater weight gain following switch among women; age >/=60 was the greatest risk factor among men. Trends for waist circumference were similar. CONCLUSIONS: Yearly weight gain increased following switch to INSTI, particularly for women, blacks and persons age >/=60. Concomitant increases in waist circumference suggest that this weight gain is associated with an increase in fat mass.