Association of Finerenone Dose and Estimated Glomerular Filtration Rate (eGFR) Slope Changes in Patients With Diabetic Kidney Disease: A Real-World Retrospective Study.

Background Finerenone demonstrates renoprotective effects in clinical trials; however, real-world evidence regarding the association between maintenance doses (10 mg vs. 20 mg) and estimated glomerular filtration rate (eGFR) slope changes remains scarce. We investigated the real-world impact of finerenone dosage and baseline clinical factors on eGFR slope trajectory in patients with diabetic kidney disease (DKD). Methods We retrospectively analyzed 104 patients with DKD who initiated finerenone and completed at least six months of follow-up. The primary outcome was the change in annual eGFR slope from the one-year pre-initiation period to the six-month post-initiation period. Secondary outcomes included changes in urinary albumin-to-creatinine ratio (UACR), urinary protein-to-creatinine ratio (UPCR), serum potassium, and blood pressure. Multivariable linear regression analysis was conducted to identify independent baseline factors associated with eGFR slope improvement. Results Following finerenone initiation, the overall eGFR slope improved from -5.20 to +0.27 mL/min/1.73 m²/year (p = 0.0144). Among subgroup analyses, significant slope improvement was observed in patients maintained on the 10 mg/day dose (n = 52, from -7.11 to +3.35 mL/min/1.73 m²/year, p = 0.00041), whereas the 20 mg/day group (n = 52) remained in a stable trajectory (-3.29 to -2.85 mL/min/1.73 m²/year, p = 0.865). In multivariable analysis, concomitant sodium-glucose cotransporter 2 (SGLT2) inhibitor use (B = +9.79, p = 0.016), younger age, lower baseline eGFR, and lower body mass index were independently associated with slope improvement. UACR decreased significantly (p = 0.0098), while serum potassium increased modestly (+0.086 mmol/L, p = 0.045) without clinically meaningful blood pressure changes. Conclusions Finerenone significantly attenuated eGFR decline in real-world patients with DKD, with slope improvement observed in patients maintained on the 10 mg/day dose. Concomitant SGLT2 inhibitor use was independently associated with greater improvement in eGFR slope, supporting the clinical utility and practical dose management of finerenone in routine practice.