Kidney Week

Abstract: SA-PO0076

Routine Urine Profiling in Sepsis-Associated AKI: Cost-Effective Tool for Risk Stratification and Targeted Post-AKI Care

Session Information

• AKI: Clinical Diagnostics and Biomarkers
  November 08, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 102 AKI: Clinical, Outcomes, and Trials

Authors

• Nusshag, Christian, Universitat Heidelberg Medizinische Fakultat Heidelberg, Heidelberg, BW, Germany

Christian Nusshag, MD, DrMed

• Tavris, Bengi Su, Universitat Heidelberg Medizinische Fakultat Heidelberg, Heidelberg, BW, Germany

Bengi Su Tavris, MD

• Morath, Christian, Universitat Heidelberg Medizinische Fakultat Heidelberg, Heidelberg, BW, Germany

Christian Morath, MD

• Zeier, Martin G., Universitat Heidelberg Medizinische Fakultat Heidelberg, Heidelberg, BW, Germany

Martin G. Zeier, MD, MS, MSc, FASN

• Weigand, Markus A., Universitat Heidelberg Medizinische Fakultat Heidelberg, Heidelberg, BW, Germany

Markus A. Weigand

• Brenner, Thorsten, Universitatsklinikum Essen, Essen, NRW, Germany

Thorsten Brenner, MD, PhD

Group or Team Name

• Nusshag Lab.

Background

Proteinuria is an established risk factor for CKD progression, but the diagnostic utility of routine urine parameters in early AKI is unclear. We investigated longitudinal changes in routine urine markers (ACR, PCR, osmolality, α1M, IgG) in patients with sepsis-associated AKI (SA-AKI), evaluating associations with kidney outcomes and overall survival.

Methods

200 ICU patients fulfilling Sepsis-3 criteria were enrolled. Urinary biomarkers were measured daily for 7 days. The primary endpoint was KRT or death within 7 days of ICU admission. Secondary endpoints included AKI severity (AKI 0/I vs. II/III without KRT) and survival at 7, 30, 90, and 365 days. AKI was staged per KDIGO criteria. AUROC analysis, Kaplan–Meier estimates, log-rank tests, and Cox regression were applied.

Results

Patients meeting the primary endpoint (N=42) showed persistently elevated ACR/PCR and reduced osmolality. In contrast, AKI II/III patients w/o KRT (N=96) exhibited declining ACR/PCR and rising osmolality after 24h of sepsis therapy, independent of urine output. AKI 0/I patients (N=62) maintained low ACR/PCR and high osmolality throughout (Fig.1). At baseline, osmolality most accurately predicted the primary endpoint (AUROC 0.78 [95% CI: 0.71–0.84]), followed by PCR (0.72), ACR (0.71), IgG (0.68) and α1M (0.56). Thresholds associated with improved survival included ACR ≤ 66 mg/gCr, PCR ≤ 1.5 g/gCr, IgG ≤ 27 mg/L, and osmolality > 450 mOsm/kg; α1M was not predictive (Fig.2). After adjustment for age, CKD and gender, ACR ≤ 66 mg/gCr and PCR ≤ 1.5 g/gCr remained independently associated with lower 30- and 365-day mortality: ACR Hazard Ratio (HR) 0.18 (95% CI: 0.06–0.50) and 0.51 (0.31–0.83); PCR HR 0.31 (0.17–0.56) and 0.59 (0.38–0.90), respectively. Importantly, results were consistent when adjusting for AKI severity instead of CKD.

Conclusion

Routine urine profiling may be a cost-effective tool for risk stratification in SA-AKI, enabling timely identification of high-risk patients and supporting targeted post-AKI care.

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025ndhsvwwj