Computed Tomography-Measured Subcutaneous Adipose Tissue as a Protective Factor in Patients with Sepsis-Associated AKI Undergoing Continuous Kidney Replacement Therapy

Background: The obesity paradox, a phenomenon in which obese patients exhibit improved survival compared to normal weight patients, has been observed in sepsis. However, body mass index does not adequately reflect adipose tissue mass and distribution. We investigated the association between abdominal adiposity and mortality among patients with sepsis-associated acute kidney injury (SA-AKI) undergoing continuous renal replacement therapy (CRRT). Methods: Between 2011 and 2022, 1,390 adult patients with SA-AKI required CRRT at Presbyterian Medical Center. After excluding those on chronic dialysis, those who died within 24 hours of CRRT initiation, and those with missing data, 330 patients were included in the study. Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) areas were quantified at the L4-L5 level from abdominal CT scans (Figure 1). Patients were divided into tertiles based on VAT or SAT values. The second tertile served as the reference, with the first and third tertiles as low and high groups, respectively. The primary outcome was 28-day mortality. Results: In the high SAT group, 28-day survival was superior compared to the reference group, with no such difference in the low SAT group (Figure 2A). In contrast, no significant difference in 28-day survival was observed between the groups based on VAT (Figure 2B). Adjusted Cox model analysis indicated high SAT reduced 28-day mortality risk (hazard ratio: 0.675, confidence interval: 0.460 – 0.990). Conclusion: SAT, but not VAT, may provide a protective effect in patients with SA-AKI requiring CRRT.Figure 1. Adipose tissue area quantification