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Abstract: SA-PO551

Association of Body Mass Index with Outcomes in a Critically Ill Population on Renal Replacement Therapy

Session Information

Category: Acute Kidney Injury

  • 102 AKI: Clinical, Outcomes, and Trials


  • Ambruso, Sophia L., University of Colorado Denver, Denver, Colorado, United States
  • Faubel, Sarah, University of Colorado Denver, Denver, Colorado, United States
  • Griffin, Benjamin, University of Colorado, Aurora, Colorado, United States
  • Jovanovich, Anna Jeanette, Denver VA / University of Colorado, Denver, Colorado, United States
  • Kendrick, Jessica B., University of Colorado School of Medicine, Aurora, Colorado, United States
  • You, Zhiying, UC Denver, Aurora, Colorado, United States
  • Palevsky, Paul M., University of Pittsburgh/VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, United States

The prevalence of obesity is rising in the critically ill population. Acute kidney injury (AKI) is a common complication seen in the intensive care unit (ICU) with 5% requiring renal replacement therapy (RRT). Limited data exists on the association of body mass index (BMI) and outcomes in patients on RRT in the ICU. In our study, we investigated the impact of very high and very low BMI on mortality rates.


We conducted a secondary analysis of the Acute Renal Failure Trial Network (ATN) database, which compared less-intensive to more-intensive RRT dosing in the ICU population with AKI. Weights >128.5kg, which exceeded the max dosing capabilities of the Prisma machine at the time, were excluded. In this analysis, patients were categorized into BMI quintiles; Q1 (<23.5kg/m2, n=173), Q2 (23.5-26.2kg/m2, n=174), Q3 (26.21-28.39kg/m2, n=173), Q4 (28.4-32.77kg/m2, n=174) and Q5 (≥32.78kg/m2, n=174). Q3 was the comparison value. Our primary endpoint was 60-day mortality. Logistic regression was used to adjust for demographics, SOFA score, Charlson score and treatment strategy.


Participants were mainly white (79%) males (70%) with a mean age of 60 ± 15.3 and overall mortality rate of 52%. Those in the highest quintile of BMI had a lower mortality rate (mortality rate 44% vs. 53%, 59%, 51% and 56% in quintiles 1,2,3 and 4, respectively). However, compared to quintile 3, those in the highest quintile did not have significantly lower odds of mortality in unadjusted or adjusted models. Compared to quintile 3, lower quintiles of BMI did not have a significant association with mortality.


Very high and very low BMI was not associated with an increased risk of mortality in critically ill patients requiring RRT. The small number of patients per quintile limited the power of this study. Larger studies analyzing the impact of BMI on mortality in critically ill patients with AKI is needed.

Multivariate analysis for 60-day ICU mortality
 Odds Ratio (95% CI)
Unadjusted Model 1 Model 2
Q11.0 (0.69-1.6)1.1 [0.7-1.7]1.2 [0.7-1.9]
Q21.3 [0.88-2.0]1.3 [0.9-2]1.3 [0.8-2.1]
Q41.2 [0.78-1.8]1.2 [0.8-1.9]1.3 [0.9-2.1]
Q50.7 [0.5-1.11]0.8 [0.5-1.2]0.8 [0.5-1.0]

Model 1: Age, race, gender Model 2: SOFA score, Charlson score, Treatment strategy + Model 1