Kidney Week

Abstract: TH-PO0728

Uremic Toxin Levels, Serum Urea Nitrogen (BUN), and Creatinine in Patients with AKI Before CKRT

Session Information

• AKI: Critical Care, CKRT, Cardiorenal Syndromes, and Clinical Outcomes
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 102 AKI: Clinical, Outcomes, and Trials

Authors

• Park, Samel, Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States

Samel Park, DrMed

• Budnick, Isadore, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States

Isadore Budnick, MD

• Li, Amy Shijia, Oregon Health & Science University, Portland, Oregon, United States

Amy Shijia Li, MD

• Carniglia, Giada, Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States

Giada Carniglia, MS, MSc

• Reisz Haines, Julie A., University of Colorado Anschutz Medical Campus Department of Biochemistry and Molecular Genetics, Aurora, Colorado, United States

Julie A. Reisz Haines, PhD

• Okamura, Kayo, Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States

Kayo Okamura

• He, Zhibin, Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States

Zhibin He, MS

• Miyazaki, Makoto, Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States

Makoto Miyazaki, PhD

• Foulon, North, Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States

North Foulon

• Madison, David, Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States

David Madison

• Blaine, Rachel, Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States

Rachel Blaine

• Campbell, Ruth E., Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States

Ruth E. Campbell, DO, MS

• Colbert, James F., Division of Infectious Disease and Geographic Medicine, Department of Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States

James F. Colbert, MD

• Griffin, Benjamin R., Division of Nephrology and Hypertension, Department of Medicine, University of Iowa Health Care, Iowa City, Iowa, United States

Benjamin R. Griffin, MD, MS, FASN

• Faubel, Sarah, Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States

Sarah Faubel, MD

Background

Uremia is a clinical syndrome associated with kidney failure caused by accumulation of metabolic waste products known as uremic toxins (UTs). BUN and creatinine are widely used surrogates for uremia and severity of kidney failure in patients with AKI. However, how well BUN and creatinine reflect UT levels in patients with AKI is unknown.

Methods

Plasma levels of BUN, creatinine, and 21 UTs were measured in 89 patients with AKI prior to anticipated CKRT. Associations of individual UTs with BUN, creatinine, and AKI duration were assessed using Spearman correlation analysis. UT levels were compared across BUN ≥100 versus <100 mg/dL, creatinine-based KDIGO stages, and AKI duration categories. Louvain analysis based on Spearman correlation coefficients was used to identify UT modules among UTs, BUN, and creatinine.

Results

Table 1 summarizes the characteristics of the 21 UTs identified in this study, together with the results of correlation and group-comparison analyses. Guanidinosuccinic acid, hypoxanthine, and quinolinic acid were significant across all six analyses. Figure 1 shows correlations among 21 UTs, BUN, and creatinine. Louvain algorithm further identified biologically interpretable modules, including a BUN/creatinine-linked module, a gut-microbiome-associated module, and a tryptophan metabolism-related module.

Conclusion

Due to heterogeneity, neither BUN nor creatinine can be used as a surrogate for global UT accumulation. Our findings support avoidance of specific cut points to define uremia and suggest further investigation of our novel UT modules in relation to AKI phenotypes and outcomes.

Funding

• Commercial Support – Baxter Investigator Initiated Grant