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.
To the Editor,
I read with great interest the Ross et al article “Obesity and Mortality Risk in Critically Ill Children,” where Ross and his colleagues investigate the association between obesity and PICU mortality. (1) Since obesity has become a nationwide concern due to obesity rates in the United States being so high, I believe that other individuals would be very interested in reading this article and the comments to follow.
I really appreciated the fact that this study included height as one of its main factors of interest due to other studies not taking it into consideration. You cannot conclude that a child is indeed obese without taking into account their weight for height ratio. Some children can weigh too much for their age but in fact be within the normal weight range for their height. A child that is 4’0 weighing 120 pounds is a totally different scenario than a child who is 5’0 weighing the same and I think it was a very logical for this study to understand that when performing their research.
If weight for age was used rather than weight for height, I think this study would have been a lot more misleading with their information. This is shown in Figure 3 and Ross et al states, “when examining individual patients, only 46,405 of 127,607 patients were classified into the same z-score grouping using weight for age and weight for height/BMI.” (1)
It is stated that the patients’ information came from 50 different PICUs around the United States and it leads me to become curious as to whether the location of the hospital was taken into consideration at all. Environment has a lot to do with an individual’s weight such that in 2012 Alaska and Virginia had the highest rates of obesity for children aged 2-5 years old. (2) If the patients’ information only came from certain states then the quality of their information may be somewhat misleading. PICU information from 50 different hospitals but only 10 different states would be only a small portion size and could potentially lead to inaccurate results. The bigger the sample size the more accurate the research will be and I think they should have tried to receive PICU information from every state in the United States if possible to make their research that much better.
In the hopes of finishing my college career with a degree as an occupational therapist, I found the Ross et al study to be very enticing. Any health care professional can relate to the fact that obesity has become a very serious problem globally over the last decade or so. Finding ways to educate and promote healthy lifestyles is the key to lowering obesity rates as well as mortality rates.
(1.) Ross, P. A., Newth, C. J., Leung, D., Wetzel, R. C., & Khemani, R. G. (2016, March). Obesity and Mortality Risk in Critically Ill Children. Pediatrics: Official Journal of the American Academy of Pediatrics, 137(3). Retrieved from http://pediatrics.aappublications.org/content/137/3/e20152035
(2.) StateofObesity.org. (2013). Childhood Obesity Trends. Retrieved from http://stateofobesity.org/childhood-obesity-trends/
Kylie M. Kaiding
Health Studies-Occupational Therapy student
Utica College
1600 Burrstone Rd
Utica, NY 13502