Association of finerenone with graded proteinuria improvement in type 2 diabetes with chronic kidney disease and proteinuria >1 g/d: a retrospective cohort study.

Background: Current evidence for finerenone in T2DM with CKD is derived primarily from patients with microalbuminuria to macroalbuminuria, and data in those with moderate-to-heavy proteinuria remain limited. This study aimed to investigate the effect of finerenone on sustained graded improvement of 24h-UTP and its safety profile in T2DM patients with CKD and proteinuria >1 g/d. Methods: This retrospective cohort study included patients with T2DM and CKD with proteinuria >1 g/d treated at hospital. Patients were divided into the finerenone group and the control group based on whether they received finerenone during the follow-up period. Proteinuria was graded as Stage 2 (1-3.5 g/d) and Stage 3 (>3.5 g/d). The primary endpoint was sustained graded improvement in 24h-UTP. The secondary endpoint was the percentage reduction in proteinuria from baseline at different timepoints. Propensity score weighting was applied to address baseline imbalances. Logistic regression and Kaplan-Meier analysis were used to assess the association between finerenone use and graded proteinuria improvement. A mixed model for repeated measures (MMRM) was employed to compare changes in 24h-UTP, eGFR, and serum potassium levels between the two groups. Safety outcomes included hyperkalemia incidence. Results: A total of 134 patients were included in this study, comprising 53 in the finerenone group and 81 in the control group. Over 12 months, 28 patients (52.8%) in the finerenone group and 27 patients (33.3%) in the control group achieved sustained graded improvement in 24h-UTP. After propensity score weighting, finerenone use was independently associated with sustained graded improvement (OR 1.26, 95% CI 1.07-1.47, P = 0.004). Kaplan-Meier analysis showed a significant difference in time to sustained improvement between groups (Log-rank P = 0.026-0.033). MMRM analysis revealed a greater reduction in 24h-UTP in the finerenone group, while eGFR and serum potassium changes did not differ significantly between groups. Conclusions: In patients with T2DM and proteinuria >1 g/d, finerenone increased the probability of sustained graded proteinuria improvement, shortened the time to improvement, and was not associated with a significantly increased risk of hyperkalemia over 12 months, although the interpretation of safety findings is limited by baseline differences in kidney function and concomitant medication use between groups.