Progressive increases in fat mass occur in adults living with HIV on antiretroviral therapy, but patterns differ by sex and anatomic depot.

Objectives: Although weight gain on ART is common, the long-term trajectory of and factors affecting increases in fat mass in people living with HIV are not well described.

Methods: Men and women living with HIV in the Modena HIV Metabolic Clinic underwent DXA scans every 6-12 months for up to 10 years (median 4.6 years). Regression modelling in both combined and sex-stratified models determined changes in and clinical factors significantly associated with trunk and leg fat mass over the study period.

Results: A total of 839 women and 1759 men contributed two or more DXA scans. The baseline median age was 44 years and BMI 22.9 kg/m2; 76% were virologically suppressed on ART at baseline. For both sexes, trunk and leg fat consistently increased over the study period, with mean yearly trunk and leg fat gain of 3.6% and 7.5% in women and 6.3% and 10.8% in men, respectively. In multivariate analysis, factors associated with greater fat mass included female sex, per-year ART use (specifically tenofovir disoproxil fumarate and integrase strand transfer inhibitor therapy), per-unit BMI increase, no self-reported physical activity and CD4 nadir <200 cells/mm3.

Conclusions: Among people living with HIV on ART, trunk and leg fat mass increased steadily over a median of 4.6 years of follow up, particularly among women. After controlling for traditional risk factors, HIV- and ART-specific risk factors emerged.