title: Resting energy expenditure, weight loss, and altered body composition in HIV infection.
abstract: Failure to downregulate resting energy expenditure (REE) as an adaption to anorexia or malabsorption is often stated as the major cause of weight loss in individuals with AIDS. In a prospective study, REE was compared with weight changes in HIV-infected patients. The impact of altered body composition on REE was reassessed by critical review of the literature. Patients were 65 male HIV-infected patients, 28 with recent weight loss (WL), and 37 who were weight stable (WS); 50/65 patients had AIDS, and 29/65 had acute infections; 29 male healthy persons served as controls. Indirect calorimetry, prospective intake protocol, and bioelectrical impedance analysis were performed. Absolute REE was lower in WL patients than in controls (1459 +/- 309 versus 1711 +/- 151 kcal/d, p < 0.001) and in WS patients (1625 +/- 402 kcal/d, p < 0.05). REE/kg body cell mass (BCM) was higher in WL and WS than in controls (both p < 0.01) due to lower BCM in both patient groups (p < 0.001). REE (%Harris-Benedict) was not different among the three groups. Weight changes around the measurement were not correlated to REE (r2 = 0.0008, p = 0.82). REE was independent of diarrhea, acute infection, fever, or caloric intake. REE had a stronger correlation to body weight and to Harris-Benedict's prediction than to fat-free mass or BCM. REE explains < 1% of weight changes. Many patients can downregulate REE as an adaption to anorexia and/or malabsorption. Higher REE/kg BCM does not signify hypermetabolism at the cellular level but can be explained by the maintenance of energy-consuming visceral tissue within the BCM during BCM loss.
authors.affiliation: Department of Internal Medicine I, University of Cologne, Germany. achim.schwenk@univ.koeln.de
authors.forename: A
authors.initials: A
authors.lastname: Schwenk
authors.forename: E
authors.initials: E
authors.lastname: Höffer-Belitz
authors.forename: B
authors.initials: B
authors.lastname: Jung
authors.forename: G
authors.initials: G
authors.lastname: Kremer
authors.forename: B
authors.initials: B
authors.lastname: Bürger
authors.forename: B
authors.initials: B
authors.lastname: Salzberger
authors.forename: V
authors.initials: V
authors.lastname: Diehl
authors.forename: M
authors.initials: M
authors.lastname: Schrappe
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000503:physiopathology; D000328:Adult; D001823:Body Composition; D002153:Calorimetry, Indirect; D003967:Diarrhea / Q000150:complications; D017097:Electric Impedance; D002149:Energy Intake; D004734:Energy Metabolism; D005334:Fever; D015658:HIV Infections / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D007239:Infections / Q000150:complications; D008297:Male; D012146:Rest; D015431:Weight Loss