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Kidney Week

Abstract: FR-PO043

Effects of Obesity on Mortality in Critically Ill Patients with AKI

Session Information

Category: Acute Kidney Injury

  • 102 AKI: Clinical, Outcomes, and Trials

Authors

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

The prevalence of obesity is rising in the critically ill population, but little data exists on outcomes in critically ill obese patients with acute kidney injury (AKI) requiring renal replacement therapy (RRT). In this study, we assessed the impact of obesity on rates of mortality in patients with AKI initiated on RRT.

Methods

We conducted a secondary analysis of the Acute Renal Failure Trial Network (ATN) database, which compared less-intensive to more-intensive RRT dosing strategies in critically ill patients. Weights >128.5 kg, exceeding the max dose capabilities of the Prisma machine at the time, were excluded. Modalities used were CVVHDF and HD, often with cross-over during the admission. In the overweight patients who received CVVHDF, 88% received a dose reduction. The overweight group was defined as ‘actual weight 30% greater than ideal body weight’. We categorized patients into an overweight group and a standard weight group (all other patients). A subgroup analysis looked separately at those who received CVVHDF at some point during the admission (CVVHDF group) and those who received no CVVHDF (HD only group). Our primary outcome was 60-day mortality. We used logistic regression to adjust for demographics, SOFA score and Charlson score.

Results

In the combined CVVHDF and HD cohort, the 60-day mortality rate was 45% (n=235, mean BMI 35.1) in the overweight group and 55% (n=633, mean BMI 25.7) in the standard weight group. Compared to the standard weight group, the overweight group had a 45% improved odds of survival, which persisted after illness severity adjustments (OR 0.55 [95% CI, 0.32-0.90]; p=0.016). Among patients receiving HD only, the overweight group had improved odds of survival (OR 0.42 [95% CI 0.21-0.84]; p=0.015). In contrast, there was no survival benefit in the overweight patients receiving CVVHDF (OR 0.83 [95% CI 0.52-1.21]; p=0.3).

Conclusion

Overweight patients with AKI had improved survival compared to the standard weight group. However, the survival benefit was only observed in overweight patients who received HD only, not CVVHDF. This benefit seems to parallel the protective effect of obesity seen in outpatient HD populations. Loss of benefit in the CVVHDF group is likely multifactorial. More outcomes studies in overweight and obese patients with AKI in the ICU are needed.