Abstract: SA-PO0068
Lower Spot Urine Creatinine-to-Osmolality Ratio as an Indicator of Acute Decline in Estimated Glomerular Filtration Rate
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
Author
- Hsu, Shih-Ping, Far Eastern Memorial Hospital, New Taipei City, Taiwan
Background
A spot urine creatinine-to-osmolality ratio (UCrOsm) quantifies urinary creatinine (Cr) excretion relative to accompanying osmoles within an intervoid interval. Lower values may indicate reduced Cr excretion, suggesting renal dysfunction. This study investigates its association with estimated glomerular filtration rate (eGFR).
Methods
A cross-sectional analysis was performed on 3,316 non-hospitalized adults from the NHANES 2011–2012. The ratio of UCrOsm to serum Cr (UCrOsm/SCr) was used as a surrogate for Cr clearance rate, while eGFR was estimated using MDRD and 2021 CKD-EPI equations. Subgroup analysis was conducted on individuals with eGFR < 60 mL/min/1.73m2.
Results
The study population had a mean age of 45 ± 17 years, with 45% female and 24% identifying as Black. Mean serum Cr was 0.89 ± 0.34 mg/dL, and mean UCrOsm was 0.19 ± 0.08. The eGFR estimates were 93 ± 24 mL/min/1.73m2 (MDRD) and 98 ± 21 mL/min/1.73m2 (CKD-EPI). UCrOsm/SCr exhibited significant positive correlations with eGFR (P < 0.001), with enhanced correlations in participants with eGFR < 60 mL/min/1.73m2 (R2= 0.374 and 0.412). (Fig. A) Discrepancies between eGFR inferred from UCrOsm/SCr and standard estimates were within ±15% for 50% of cases and within ±30% for 80% of participants. (Fig. B) Notably, UCrOsm correlated with these discrepancies (ρ = 0.390 to 0.601); (Fig. C) for values below 0.08 (5th percentile), median discrepancies ranged from -25.8% to -55.3%. (Fig. D)
Conclusion
UCrOsm may serve as a surrogate marker for eGFR estimation, particularly in individuals with eGFR < 60 mL/min/1.73m2. Values below the 5th percentile, indicating at least a 26% decline in eGFR, may portend worsening acute kidney injury. These findings highlight the potential role of UCrOsm in screening for acute renal dysfunction in non-hospitalized populations.