Trajectories of Albuminuria and Non‐Albumin Proteinuria After Sequential Addition of Finerenone for Residual Albuminuria Despite Established SGLT2 Inhibitor Therapy in Diabetic Kidney Disease: A Real‐World Cohort Study

ABSTRACT Aims CONFIDENCE evaluated simultaneous initiation of finerenone and an SGLT2 inhibitor (SGLT2i). We examined 12‐month trajectories of albuminuria and non‐albumin proteinuria after finerenone was added to established SGLT2i therapy. Materials and Methods This single‐centre retrospective cohort study included 86 patients with type 2 diabetes treated with finerenone after SGLT2i therapy. Urinary albumin‐to‐creatinine ratio (UACR), protein‐to‐creatinine ratio (UPCR) and non‐albumin protein‐to‐creatinine ratio (UNAPCR) were measured before SGLT2i initiation (T1) and finerenone initiation (T2), at the first post‐finerenone assessment (median 1.6 months), and at 6 and 12 months. Covariate‐adjusted linear mixed‐effects models of log‐transformed markers estimated geometric mean changes from T2, with Holm adjustment across 12 primary contrasts. Results Urinary markers showed no significant net changes between T1 and T2. After finerenone initiation, UACR decreased by 46.2% at the first post‐finerenone assessment and remained 35.2% lower at 12 months (95% confidence interval [CI], −47.1 to −20.7); corresponding reductions were 39.9% and 23.1% for UPCR and 33.7% and 13.6% for UNAPCR. All reductions were significant except for UNAPCR at 12 months (adjusted p = 0.16). At 12 months, 39 of 76 patients (51.3%) achieved a UACR reduction ≥ 30%. Mean serum potassium level increased from 4.6 to 4.8 mmol/L and plateaued; levels > 5.5 and > 6.0 mmol/L occurred in 17.4% and 4.7% of patients, respectively. Conclusions In patients with residual albuminuria despite established SGLT2i therapy, finerenone addition was associated with sustained 12‐month reductions in albuminuria and total proteinuria and an early reduction in non‐albumin proteinuria that attenuated by 12 months. Prospective confirmation is warranted.