Finerenone in Patients With Chronic Kidney Disease and Type 2 Diabetes According to Baseline HbA_1c and Insulin Use: An Analysis From the FIDELIO-DKD Study

OBJECTIVE Finerenone significantly improved cardiorenal outcomes in patients with chronic kidney disease (CKD) and type 2 diabetes (T2D) in the Finerenone in Reducing Kidney Failure and Disease Progression in Diabetic Kidney Disease trial. We explored whether baseline HbA_1c level and insulin treatment influenced outcomes. RESEARCH DESIGN AND METHODS Patients with T2D, urine albumin-to-creatinine ratio (UACR) of 30–5,000 mg/g, estimated glomerular filtration rate (eGFR) of 25 to <75 mL/min/1.73 m²,andtreated with optimized renin–angiotensin system blockade were randomly assigned to receive finerenone or placebo. Efficacy outcomes included kidney (kidney failure, sustained decrease ‡40% in eGFR from baseline, or renal death) and cardiovascular (cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure) composite endpoints. Patients were analyzed by baseline insulinuseandbybaselineHbA_1c <7.5% (58 mmol/mol) or ‡7.5%. RESULTS Of 5,674 patients, 3,637 (64.1%) received insulin at baseline. Overall, 5,663 patients were included in the analysis for HbA_1c; 2,794 (49.3%) had baseline HbA_1c <7.5% (58 mmol/mol). Finerenone significantly reduced risk of the kidney composite outcome independent of baseline HbA_1c level and insulin use (P_interaction =0.41 and 0.56, respectively). Cardiovascular composite outcome incidence was reduced with finerenone irrespective of baseline HbA_1c level and insulin use (P_interaction = 0.70 and 0.33, respectively). Although baseline HbA_1c level did not affect kidney event risk, cardiovascular risk increased with higher HbA_1c level. UACR reduction was consistent across subgroups. Adverse events were similar between groups regardless of baseline HbA_1c level and insulin use; few finerenone-treated patients discontinued treatment because of hyperkalemia. CONCLUSIONS Finerenone reduces kidney and cardiovascular outcome risk in patients with CKD and T2D, and risks appear consistent irrespective of HbA_1c levels or insulin use.