Preswitch Regimens Associated With Weight Gain Among Persons With HIV who Switch to Integrase Inhibitor-Containing Regimens.

Background: Weight gain associated with integrase strand transfer inhibitors (INSTIs) is well documented. However, recent reports suggest that the observed weight gain among persons who switch to INSTIs may be associated with their preswitch regimen.

Methods: We conducted retrospective analyses of persons with HIV on antiretroviral therapy who switched to a second-generation INSTI-containing regimen (bictegravir/dolutegravir) at the Duke Adult Infectious Diseases Clinic (Durham, NC, USA) between 2014 and 2021. The outcome was weight change, operationalized as percent weight change, absolute weight change (kg), gaining ≥5% of preswitch weight, and gaining ≥10% of preswitch weight. The primary exposure was preswitch regimen.

Results: Our analysis included 750 persons. Cohort demographics were as follows: mean age (SD) 51 (11) years, 30% female at birth, 58% Black, 4% Hispanic ethnicity. At regimen switch, the mean CD4 count was 701 cells/mm³, and 68% had a viral load ≤20 copies/cc. Persons with preswitch regimens containing efavirenz had higher odds of gaining ≥5% body weight (odds ratio [OR], 1.62, 95% CI, 1.13-2.32) and ≥10% body weight (OR, 1.68; 95% CI, 1.02-2.73) after regimen switch, adjusted for age, sex, race, ethnicity, and preswitch body mass index. Persons with preswitch regimens containing tenofovir disoproxil (TDF) also had higher odds of gaining ≥5% body weight (OR, 1.64; 95% CI, 1.17-2.30).

Conclusions: Preswitch regimens containing efavirenz and TDF were associated with significant weight gain after switching to INSTI-based regimens. Our findings support the hypothesis that the weight gain observed with switching to INSTI-based regimens could be driven by stopping medications with weight-suppressing properties.