Increases in weight and fat gains with antiretroviral treatment (ART) are serious problems in people with HIV (PWH), but the pathogenesis is poorly understood. Some have suggested changes in resting metabolic rate (RMR) and/or caloric intake are responsible, but no data exists. We examined changes in RMR, oxygen consumption (V02), and dietary intake and associations with changes in weight and body composition after ART initiation.
ART-naïve PWH were prospectively enrolled and underwent a comprehensive clinical and laboratory assessment at baseline and at 6 and 12 months after ART initiation. Fasting RMR/V02 and body composition were measured by indirect calorimetry and whole-body DXA, resp. Nutrient intake was assessed by a registered dietician via 24-hour dietary recalls x3 at each time point and analyzed using dietary analysis software. Changes in variables and associations were assessed using linear mixed effects models.
30 PWH were enrolled (mean age: 31 yrs, 77% male, 74% black; mean baseline CD4 444 cells/mm3; HIV RNA 267,148 copies/mL, BMI 28.6 kg/m2, RMR 1420 kcal/day, V02 205 mL/min, 1690 total kcal average daily intake). All but 1 initiated an integrase inhibitor-based regimen (53% DTG; 37% TAF). By 6 and 12 months, all but 3 and 1 participant, respectively, had an HIV RNA <200 copies/mL. At both time points, there was a significant increase in mean weight, total fat and trunk fat (6 mo/12 mo: +3.8/+10.2 kg, +2.4/+4.6 kg, +1.6/+3.4 kg, resp; all P<0.05), but a nonsignificant increase in total lean body mass (+1.7/+2.7 kg; P=0.09/P=0.71). Over the study period, there were no significant changes in RMR, V02 or dietary intake (kcal, total fat, saturated fat, fiber, protein, total sugars, fructose, branched-chain amino acids, or arginine) (all P>0.70). All body composition changes were significant after adjusting for sex, baseline HIV RNA and RMR (or V02) at both time points except for lean body mass at 12 months.
Significant increases in weight and fat gains were seen after ART initiation, despite a lack of significant changes in RMR, V02 or diet. All body composition changes except for lean body mass at 12 months were significant after adjusting for RMR or V02. These data do not support the hypothesis that changes in RMR or caloric intake are responsible for increases in weight and fat gains after ART initiation in PWH.