Management of chronic kidney disease (CKD) in type 1 diabetes remains challenging, particularly in individuals with longstanding disease and variable glycemic control. A study published in Diabetes Care evaluated whether the efficacy and safety of finerenone differed according to baseline glycated hemoglobin (HbA1c) levels and diabetes duration in adults with type 1 diabetes and CKD.

In this randomized study, adults with type 1 diabetes, urinary albumin-to-creatinine ratio (UACR) between 200 and <5,000 mg/g, and estimated glomerular filtration rate (eGFR) between 25 and <90 mL/min/1.73 m² were assigned in a 1:1 ratio to finerenone or placebo. The primary analysis evaluated change in UACR from baseline over 6 months according to baseline HbA1c and diabetes duration tertiles.

Findings

• Baseline HbA1c data were available for 240 of 242 participants. Mean HbA1c was 7.6% (60 mmol/mol), mean diabetes duration was 32.0 years, and mean eGFR was 58.9 mL/min/1.73 m².
• Over 6 months, HbA1c remained stable in both groups, with a between-group difference of +0.04% (95% CI −0.17% to 0.24%; P=0.74).
• Median UACR decreased from 574.6 to 373.5 mg/g with finerenone and from 506.4 to 475.6 mg/g with placebo, corresponding to a placebo-corrected reduction of 25% (95% CI −35% to −13%; P=0.0001).
• Placebo-corrected UACR reductions across HbA1c tertiles were −17% for HbA1c <7.1%, −18% for HbA1c ≥7.1% to ≤8.1%, and −37% for HbA1c >8.1% (P interaction=0.41).
• Albuminuria-lowering effects were also consistent across diabetes duration tertiles (P interaction=0.70).
• Overall safety outcomes and hyperkalemia incidence were similar across HbA1c subgroups.

The analysis showed that finerenone reduced albuminuria in adults with type 1 diabetes and CKD irrespective of baseline HbA1c level or diabetes duration. Glycemic control remained stable during treatment, and the safety profile was generally consistent across glycemic subgroups.