Resting Energy Expenditure in Asymptomatic HIV-Infected Females

The purpose of this study was to investigate whether resting energy expenditure (REE) is elevated in early, asymptomatic human immunodeficiency virus (HIV)-infected females and to study the contribution of a cytokine, tumor necrosis factor- alpha (TNF-alpha), to hypermetabolism. Cross-sectional comparison of REE in asymptomatic HIV+ females and a control group matched for age, body mass index (BMI), and fat-free mass (FFM). Twenty-six females aged 35 +/- 7 years (10 HIV+ [mean CD4 + T cell count 636/mm3] and 16 healthy controls) participated in this study. REE was measured by indirect calorimeter using a Deltatrac ventilated hood with a continuous rate of 40 L/min for 30 minutes after a 40-minute equilibrium period. All tests were performed after a 12-hour overnight fast. Twenty-four-hour urinary nitrogen was calculated to correct for respiratory quotient. Body composition was measured by bioelectrical impedance (BioAnalogics, Beaverton, OR). TNF-alpha was measured by ELISA (R & D Systems, Minneapolis, MN). Absolute REE was 17% higher (1755 kcal/kg +/- 410 versus 1497 kcal/kg +/- 197) in the HIV+ group compared with the control group (p<0.05). REE remained significantly higher in the HIV+ group when REE was adjusted for body composition differences (p=0.04). Results revealed a 23% higher level of TNF-alpha in the HIV+ subjects (p<0.01); however, only a weak correlation existed between TNF-alpha and REE (r=.352). This study documented that hypermetabolism and elevated TNF-alpha exist in HIV+ females in the early stages of disease.