title: Fat mass protects hospitalized elderly persons against morbidity and mortality.
abstract: BACKGROUND
  It is well established that the combination of protein-energy malnutrition and low body mass index (BMI) increases the risk of death in elderly patients, but recent studies indicate that the risk of death may decrease with higher body weight. However, these studies did not perform direct, separate, and reliable measurements of fat and lean mass by using a reference technique.
  
  
  OBJECTIVE
  Our objective was to evaluate the relation between body composition, based on the 4-compartment model, and morbidity and mortality in hospitalized elderly patients.
  
  
  METHODS
  This prospective study enrolled 125 elderly patients evaluated at admission for body composition on the basis of BMI plus fat mass, lean mass, appendicular skeletal muscle mass, and body cell mass indexes (calculated as the ratio of the mass to the square of the height) measured by X-ray absorptiometry and bioelectrical impedance analysis. Outcomes were assessed 6 mo later by using a score system that takes into account complications (pressure ulcers and/or infections) and 6-mo mortality.
  
  
  RESULTS
  The fat mass index correlated positively (r = 0.19 and P = 0.023 adjusted for sex; r = 0.18 and P = 0.043 adjusted for sex, albuminemia, and C-reactive protein) with outcome score (1: death, 2: complications, 3: no complications). There was no significant correlation between outcome score and BMI, lean mass, appendicular skeletal muscle mass, and body cell mass indexes.
  
  
  CONCLUSIONS
  This study clearly indicates that the generally accepted rule that overweight is associated with morbidity and mortality does not apply to hospitalized elderly patients, for whom fat mass is associated with a decreased risk of adverse events.
authors.affiliation: Hôpital Emile-Roux, Assistance Publique-Hôpitaux de Paris, Limeil-Brévannes, France. olivier.bouillanne@erx.aphp.fr
authors.forename: Olivier
authors.initials: O
authors.lastname: Bouillanne
authors.forename: Claire
authors.initials: C
authors.lastname: Dupont-Belmont
authors.forename: Phasaro
authors.initials: P
authors.lastname: Hay
authors.forename: Brigitte
authors.initials: B
authors.lastname: Hamon-Vilcot
authors.forename: Luc
authors.initials: L
authors.lastname: Cynober
authors.forename: Christian
authors.initials: C
authors.lastname: Aussel
mesh_terms: D000273:Adipose Tissue; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D009026:Mortality; D011183:Postoperative Complications / Q000453:epidemiology*; D011446:Prospective Studies; D011502:Protein-Energy Malnutrition