Nutritional Status Based on Body Mass Index Is Associated With Morbidity and Mortality in Mechanically Ventilated Critically Ill Children in the PICU. (Emrath)

Bechard LJ, et al. Nutritional Status Based on Body Mass Index Is Associated With Morbidity and Mortality in Mechanically Ventilated Critically Ill Children in the PICU. Crit Care Med. 2016 Aug;44(8):1530-7.

OBJECTIVE: To determine the influence of admission anthropometry on clinical outcomes in mechanically ventilated children in the PICU.

DESIGN: Data from two multicenter cohort studies were compiled to examine the unique contribution of nutritional status, defined by body mass index z score, to 60-day mortality, hospital-acquired infections, length of hospital stay, and ventilator-free days, using multivariate analysis.

SETTING: Ninety PICUs from 16 countries with eight or more beds.

PATIENTS: Children aged 1 month to 18 years, admitted to each participating PICU and requiring mechanical ventilation for more than 48 hours.

MEASUREMENTS AND MAIN RESULTS: Data from 1,622 eligible patients, 54.8% men and mean (SD) age 4.5 years (5.1), were analyzed. Subjects were classified as underweight (17.9%), normal weight (54.2%), overweight (14.5%), and obese (13.4%) based on body mass index z score at admission. After adjusting for severity of illness and site, the odds of 60-day mortality were higher in underweight (odds ratio, 1.53; p < 0.001) children. The odds of hospital-acquired infections were higher in underweight (odds ratio, 1.88; p = 0.008) and obese (odds ratio, 1.64; p < 0.001) children. Hazard ratios for hospital discharge were lower among underweight (hazard ratio, 0.71; p < 0.001) and obese (hazard ratio, 0.82; p = 0.04) children. Underweight was associated with 1.3 (p = 0.001) and 1.6 (p < 0.001) fewer ventilator-free days than normal weight and overweight, respectively.

CONCLUSIONS: Malnutrition is prevalent in mechanically ventilated children on admission to PICUs worldwide. Classification as underweight or obese was associated with higher risk of hospital-acquired infections and lower likelihood of hospital discharge. Underweight children had a higher risk of mortality and fewer ventilator-free days.

Obesity and Mortality Risk in Critically Ill Children.

Ross PA, et al. Obesity and Mortality Risk in Critically Ill Children. Pediatrics. 2016 Mar; 137(3):1-8.

BACKGROUND AND OBJECTIVES: 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.

Obesity, Acute Kidney Injury, and Mortality in Critical Illness. (Emrath)

Danziger J, et al. Obesity, Acute Kidney Injury, and Mortality in Critical Illness. Crit Care Med. 2016 Feb;44(2):328-34.

OBJECTIVES: Although obesity is associated with risk for chronic kidney disease and improved survival, less is known about the associations of obesity with risk of acute kidney injury and post acute kidney injury mortality.

DESIGN: In a single-center inception cohort of almost 15,000 critically ill patients, we evaluated the association of obesity with acute kidney injury and acute kidney injury severity, as well as in-hospital and 1-year survival. Acute kidney injury was defined using the Kidney Disease Outcome Quality Initiative criteria.

MEASUREMENTS AND MAIN RESULTS: The acute kidney injury prevalence rates for normal, overweight, class I, II, and III obesity were 18.6%, 20.6%, 22.5%, 24.3%, and 24.0%, respectively, and the adjusted odds ratios of acute kidney injury were 1.18 (95% CI, 1.06-1.31), 1.35 (1.19-1.53), 1.47 (1.25-1.73), and 1.59 (1.31-1.87) when compared with normal weight, respectively. Each 5-kg/m increase in body mass index was associated with a 10% risk (95% CI, 1.06-1.24; p < 0.001) of more severe acute kidney injury. Within-hospital and 1-year survival rates associated with the acute kidney injury episodes were similar across body mass index categories.

CONCLUSION: Obesity is a risk factor for acute kidney injury, which is associated with increased short- and long-term mortality.