title: Gender-specific differences in energy metabolism during the initial phase of critical illness.
abstract: OBJECTIVE
  Women and men differ in substrate and energy metabolism. Such differences may affect energy requirements during the acute phase of critical illness.
  
  
  METHODS
  Data of 155 critically ill medical patients were reviewed for this study. Indirect calorimetry in each patient was performed within the first 72 h following admission to the medical intensive care unit after an overnight fast.
  
  
  RESULTS
  In overweight (body mass index (BMI) ≥25 kg/m(2)) but not in normal-weight patients, resting energy expenditure (REE) adjusted for body weight (REEaBW) differed significantly between women and men (17.2 (interquartile range (IQR) 15.2-20.7) vs 20.9 (IQR 17.9-23.4) kcal/kg/day, P<0.01). Similarly, REE adjusted for ideal body weight (REEaIBW) was significantly lower in women compared with men (25.5 (IQR 22.6-28.1) vs 28.0 (IQR 25.2-30.0) kcal/kg/day, P<0.05). In overweight patients, gender was identified as an independent predictor of REEaBW in the multivariate regression model (r=-2.57 (95% CI -4.57 to -0.57); P<0.05), even after adjustment for age, simplified acute physiology score (SAPS II), body temperature, body weight and height.
  
  
  CONCLUSIONS
  REEaBW decreases with increasing body mass in both sexes. This relationship differs between women and men. Overweight critically ill women show significantly lower REEaBW and REEaIBW, respectively, compared with men. These findings could affect the current practice of nutritional support during the early phase of critical illness.
authors.affiliation: Intensive Care Unit, Department of Gastroenterology and Hepatology, Division of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Drolz
authors.affiliation: Intensive Care Unit, Department of Gastroenterology and Hepatology, Division of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Wewalka
authors.affiliation: Intensive Care Unit, Department of Gastroenterology and Hepatology, Division of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: T
authors.initials: T
authors.lastname: Horvatits
authors.affiliation: Intensive Care Unit, Department of Gastroenterology and Hepatology, Division of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: V
authors.initials: V
authors.lastname: Fuhrmann
authors.affiliation: Division of Internal Medicine, LKH Kirchdorf, Kirchdorf, Austria.
authors.forename: B
authors.initials: B
authors.lastname: Schneeweiss
authors.affiliation: Intensive Care Unit, Department of Gastroenterology and Hepatology, Division of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Trauner
authors.affiliation: Intensive Care Unit, Department of Gastroenterology and Hepatology, Division of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Zauner
mesh_terms: D000328:Adult; D000368:Aged; D002153:Calorimetry, Indirect; D016638:Critical Illness; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism*; D012189:Retrospective Studies; D012737:Sex Factors