Changes in Body Mass Index Over Time in People With and Without HIV Infection

Background: Excess weight gain is an important health concern among people with HIV (PWH) on antiretroviral therapy (ART). The extent to which ART contributes to body mass index (BMI) changes is incompletely understood.

Methods: We conducted a retrospective study of PWH initiating ART and demographically matched people without HIV (PWoH). Data on baseline BMI (kg/m²; categorized as underweight/normal, overweight, or obese) and ART class (integrase strand transfer inhibitor [INSTI], non-nucleoside reverse transcriptase inhibitor [NNRTI], protease inhibitor [PI]) were obtained from electronic health records. BMI was evaluated longitudinally using piecewise linear splines in mixed effects models by HIV status, baseline BMI, and ART class. Models were adjusted for sociodemographics, comorbidities, and substance use.

Results: The study included 8256 PWH and 129 966 PWoH (mean baseline age, 40.9 and 42.2 years, respectively; 88% men). In adjusted models, the average annual change in BMI in the first 2 years after ART initiation was 0.53 for PWH and 0.12 for PWoH (P < .001). BMI increases among PWH were observed for all ART classes: 0.69 for INSTIs, 0.69 for PIs, and 0.40 for NNRTIs vs 0.12 among PWoH. For PWH initiating INSTIs, BMI increases were observed regardless of baseline BMI. Overall BMI changes >2 years after ART initiation were similar by HIV status (0.02 average annual increase for PWH and PWoH).

Conclusions: PWH initiating ART gained excess weight in the first 2 years, emphasizing the importance of monitoring weight and cardiometabolic health among ART-treated PWH.