Obesity and Mortality Risk in Critically Ill Children

• Published in: Pediatrics (Evanston) 2016-03, Vol.137 (3), p.e20152035-e20152035
• Main Authors: Ross, Patrick A, Newth, Christopher J L, Leung, Dennis, Wetzel, Randall C, Khemani, Robinder G
• Format: Article
• Language: English
• Subjects: Body mass index; Child; Childhood obesity; Comorbidity; Comparative analysis; Critical Illness - mortality; Critically ill children; Health aspects; Humans; Intensive Care Units; Logistic Models; Mortality; Obesity; Obesity in children; Patient outcomes; Pediatric Obesity - epidemiology; Pediatrics; Retrospective Studies; Risk Factors; Severity of Illness Index; United States - epidemiology; Weight control
• ISSN: 0031-4005; 1098-4275
• DOI: 10.1542/peds.2015-2035

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. 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. 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. 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.