Kidney Week

Abstract: FR-PO0541

Association Between Urinary Sodium-to-Potassium Ratio and Antiproteinuric Effects of Finerenone in Patients with Diabetic Kidney Disease: A Retrospective Study

Session Information

• CKM: Clinical - Trials, Epidemiology, and Biomarkers
  October 23, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Cardiovascular-Kidney-Metabolic Health

• 602 Cardiovascular-Kidney-Metabolic Health: Clinical

Authors

• Otsuka, Tomoyuki, Department of Nephrology, Juntendo University Urayasu Hospital, Urayasu, Chiba Prefecture, Japan

Tomoyuki Otsuka, DrMed

• Sasatsuki, Yuya, Department of Nephrology, Juntendo University Urayasu Hospital, Urayasu, Chiba Prefecture, Japan

Yuya Sasatsuki, MD

• Fujishiro, Mikoto, Department of Nephrology, Juntendo University Urayasu Hospital, Urayasu, Chiba Prefecture, Japan

Mikoto Fujishiro, MD

• Okuma, Teruyuki, Department of Nephrology, Juntendo University Urayasu Hospital, Urayasu, Chiba Prefecture, Japan

Teruyuki Okuma

• Nakayama, Maiko, Department of Nephrology, Juntendo University Urayasu Hospital, Urayasu, Chiba Prefecture, Japan

Maiko Nakayama, MD

• Muto, Masahiro, Department of Nephrology, Juntendo University Urayasu Hospital, Urayasu, Chiba Prefecture, Japan

Masahiro Muto, MD, PhD

• Takahara, Hisatsugu, Department of Nephrology, Juntendo University Urayasu Hospital, Urayasu, Chiba Prefecture, Japan

Hisatsugu Takahara, DrMed

• Suzuki, Yusuke, Department of Nephrology, Juntendo University Faculty of Medicine, Bunkyo, Tokyo, Japan

Yusuke Suzuki, MD, PhD

• Suzuki, Hitoshi, Department of Nephrology, Juntendo University Urayasu Hospital, Urayasu, Chiba Prefecture, Japan

Hitoshi Suzuki, MD, PhD

Background

Finerenone, nonsteroidal mineralocorticoid receptor antagonist (MRA), has emerged as a key therapy for reducing the risk of kidney failure and cardiovascular events in patients with diabetic kidney disease (DKD). However, further investigation is needed regarding the association between long-term changes in urinary electrolytes and their anti-proteinuric effects in real-world clinical practice. This study aimed to investigate the changes in the urinary sodium-to-potassium (Na/K) ratio, a potential surrogate for MR blockade, and its clinical relevance in patients treated with finerenone.

Methods

We conducted a retrospective study of 42 patients with DKD who initiated finerenone in addition to RAS inhibitor at our institution. SGLT2 inhibitor were concomitant use in 90% of patients. Clinical and laboratory parameters, including serum creatinine (s-Cre), eGFR, urine protein-to-creatinine ratio (UPCR), and urinary Na/K ratio, were measured at baseline and throughout a 6-month follow-up period. Statistical analysis was performed to evaluate the significance of changes from baseline to 6 months.

Results

Treatment with finerenone led to a significant and sustained reduction in proteinuria; the median UPCR decreased from 1.3 at baseline to 0.87 g/gCre at 6 months (p = 0.0002). As an initial dip of renal function, median eGFR decreased from 46 mL/min/1.73m² at baseline to 42 mL/min/1.73m² at 2 months, followed by stabilization. Simultaneously, the median urinary Na/K ratio increased from 2.11 to 2.85. These data indicate that finerenone facilitates a steady reduction in proteinuria while concurrently modulating electrolyte excretion profiles, a trend that persists beyond the initial stabilization of renal function.

Conclusion

In real-world clinical practice, finerenone provides potent anti-proteinuric effects in patients with DKD even under concomitant use with SGLT2 inhibitor, characterized by long-term stabilization of renal function. Since a significant reduction in proteinuria is observed in parallel with an increase in the urinary Na/K ratio, this ratio is considered a practical and non-invasive clinical marker for monitoring the pharmacological activity and therapeutic response of finerenone.