Abstract: FR-PO0859
Single-Nephron Proteinuria and Kidney Outcomes in IgAN
Session Information
- Glomerular Outcomes: From Proteinuria to Prognosis
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Yamashita, Hiroshi, Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
- Sasaki, Takaya, Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
- Tsuboi, Nobuo, Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
- Marumoto, Hirokazu, Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
- Okabayashi, Yusuke, Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
- Haruhara, Kotaro, Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
- Kanzaki, Go, Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
- Koike, Kentaro, Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
- D'Agati, Vivette D., Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States
- Bertram, John F., Department of Anatomy and Developmental Biology, Biomedical Discovery Institute, Monash University, Melbourne, Victoria, Australia
- Yokoo, Takashi, Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
Background
Our established method for estimating nephron number, using kidney cortical volume from unenhanced computed tomography and glomerular density from kidney biopsy, enables calculation of single-nephron estimated glomerular filtration rate (SNeGFR) and urinary protein excretion (SNUPE). In IgA nephropathy, SNeGFR showed no consistent trend across chronic kidney disease stages, whereas SNUPE increased steadily, suggesting its potential as a risk factor. We investigated the associations of SNUPE and SNeGFR with kidney outcomes.
Methods
We included 222 patients whose nephron numbers were estimated by multiplying cortical volume by non-sclerotic glomerular density. SNUPE and SNeGFR were calculated by dividing UPE and eGFR by nephron number. eGFR slope was analyzed with a mixed-effects model for repeated measures, adjusted for risk factors (e.g., eGFR, UPE). Kidney replacement therapy (KRT) initiation was assessed by log-rank test.
Results
222 patients (mean age 42.7 years; 61.7% male) were followed for a median of 7.6 years. Median SNUPE and SNeGFR were 13.4 mg/day/nephron (IDI 6.0, 43.4) and 47.4 nL/min/nephron (IQI 34.2, 65.7), respectively. Higher SNUPE was significantly associated with faster eGFR decline (Fig. A). SNeGFR also showed a significant but inconsistent association (Fig. B). Higher SNUPE was linked to increased risk of KRT (Fig. C), whereas SNeGFR was not (Fig. D).
Conclusion
SNUPE may be a promising marker for kidney outcomes in patients with IgA nephropathy. Unlike SNeGFR, SNUPE may better reflect the single-nephron burden, enhancing risk stratification.