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Abstract: TH-OR042

Increased Mortality in Underweight but Not Obese Critically Ill Patients – A Secondary Analysis of the AWARE Study

Session Information

Category: Pediatric Nephrology

  • 1600 Pediatric Nephrology


  • Basu, Rajit K., Children's Healthcare of Atlanta, Atlanta, Georgia, United States
  • Ayalon, Itay, Dana-Dwek Children''s Hospital, Tel-Aviv Medical Center, Tel-Aviv, Israel
  • Woo, Jessica G., Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
  • Kaddourah, Ahmad, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
  • Goldstein, Stuart, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
  • Kaplan, Jennifer M., Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States

Obesity is a significant public health problem with an increasing prevalence in both adults and children. The effect of obesity on critical care mortality is controversial and even less is known about the effect of underweight status on mortality. We investigated the prevalence and outcomes of obesity and underweight in a large, critically ill pediatric cohort.


We conducted a secondary analysis of the prospective, observational, multinational Assessment of Worldwide Acute kidney injury, Renal angina, and Epidemiology (AWARE) study data. PICU patients, 3mos to 25yrs, were eligible but only subjects with documented age, sex, height and weight were analyzed. Patients were divided into 4 groups (under, normal, overweight and obese) based on their BMI percentile-for-age and sex according to WHO (for patients 3mos- 2yrs) and CDC criteria (for patients ≥2yrs). The primary outcome was 28d mortality. We planned for an analysis of a subgroup of septic patients.


A total of 3,719 patients were evaluated of which 542 (14%) had a primary diagnosis of sepsis. Twenty-nine percent of patients were underweight, 44% normal weight, 11% overweight and 16% obese. The 28d mortality rate was 3.5% for the entire cohort and 8.9% for the septic group and differed significantly by weight status (5.7%, 3%, 2.1% and 1.7% for under, normal, overweight and obese subjects, p<0.0001 and 14.9%, 6.5%, 3.5%, 5.3% in the septic group respectively, p=0.003). In a fully adjusted model, 28d mortality risk was 1.8-fold higher in underweight (adjusted Odds Ratio [OR] and 95%CI: 1.2-2.8]) compared to normal weight in the entire group and 3.4 [1.4-8.4] in the septic group with overweight and obese not having increased risk in both cohorts. Interestingly underweight patients had a significantly higher frequency of fluid overload >10% at day 3 (44.0% vs. 32.5%, 26.1%, 19.1% for under, normal, overweight and obese subjects, p<0.0001) without increased frequency of KDIGO-AKI or renal replacement therapy.


Underweight subjects make up a significant proportion of patients in the PICU. Underweight, not obesity, is independently associated with increased risk for mortality which may be associated to their higher frequency of fluid overload during their ICU stay.