title: Obesity and Mortality Risk in Critically Ill Children.
abstract: OBJECTIVE
  Childhood obesity is epidemic and may be associated with PICU mortality. Using a large multicenter PICU database, we investigated the association between obesity and PICU mortality, adjusting for initial severity of illness. We further investigated whether height- and weight-based classifications of obesity compared with a weight-based classification alone alter the mortality distribution.
  
  
  METHODS
  This retrospective analysis used prospectively collected data from the Virtual PICU Systems database. Height, weight, age, and gender were used to calculate z score groups based on Centers for Disease Control and Prevention and World Health Organization growth curves. A random effects mixed logistic regression model was used to evaluate the association between obesity and PICU mortality, controlling for hospital, initial severity of illness, and comorbidities.
  
  
  RESULTS
  A total of 127,607 patients were included; the mortality rate was 2.48%. Being overweight was independently associated with increased PICU mortality after controlling for severity of illness with the Pediatric Index of Mortality 2 score and preexisting comorbidities. Mortality had a U-shaped distribution when classified according to weight-for-age or weight-for-height/BMI. When classifying patients using weight-for-age without respect to height, the nadir of the mortality curve was shifted, potentially falsely implying a benefit to mild obesity.
  
  
  CONCLUSIONS
  Risk-adjusted PICU mortality significantly increases as weight-for-height/BMI increases into the overweight and obese ranges. We believe that height data are necessary to correctly classify body habitus; without such information, a protective benefit from mild obesity may be incorrectly concluded.
authors.affiliation: Department of Anesthesiology Critical Care Medicine, Children's Hospital Los Angeles, University of Southern California Keck School of Medicine, Los Angeles, California paross@chla.usc.edu.
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Ross
authors.affiliation: Department of Anesthesiology Critical Care Medicine, Children's Hospital Los Angeles, University of Southern California Keck School of Medicine, Los Angeles, California.
authors.forename: Christopher J L
authors.initials: CJ
authors.lastname: Newth
authors.affiliation: Department of Anesthesiology Critical Care Medicine, Children's Hospital Los Angeles, University of Southern California Keck School of Medicine, Los Angeles, California.
authors.forename: Dennis
authors.initials: D
authors.lastname: Leung
authors.affiliation: Department of Anesthesiology Critical Care Medicine, Children's Hospital Los Angeles, University of Southern California Keck School of Medicine, Los Angeles, California.
authors.forename: Randall C
authors.initials: RC
authors.lastname: Wetzel
authors.affiliation: Department of Anesthesiology Critical Care Medicine, Children's Hospital Los Angeles, University of Southern California Keck School of Medicine, Los Angeles, California.
authors.forename: Robinder G
authors.initials: RG
authors.lastname: Khemani
mesh_terms: D002648:Child; D015897:Comorbidity; D016638:Critical Illness / Q000401:mortality*; D006801:Humans; D007362:Intensive Care Units; D016015:Logistic Models; D063766:Pediatric Obesity / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology