Hyperkalemia risk and potassium trajectory after finerenone initiation: a real-world cohort study

Finerenone improves cardiovascular and kidney outcomes in patients with type 2 diabetes and chronic kidney disease; however, hyperkalemia remains a safety concern in routine practice. We evaluated the incidence of hyperkalemia, factors associated with its occurrence, and temporal patterns of serum potassium after finerenone initiation.

We conducted a single-center retrospective observational cohort study of patients who initiated finerenone between May 2022 and August 2025. The primary outcome was incident hyperkalemia (serum potassium ≥ 5.5 mEq/L). Candidate variables were selected using least absolute shrinkage and selection operator (LASSO)-penalized Cox regression, and associations were estimated using multivariable Cox proportional hazards models. Potassium trajectories were assessed using mixed-effects models over 12 months (6 months before and after finerenone initiation), with subgroup analyses by kidney function and baseline potassium.

Among 289 eligible patients, 280 were included (mean age 68 years; 68% male; mean baseline eGFR of 36.8 mL/min/1.73 m²). Hyperkalemia occurred in 38 patients. Incident hyperkalemia was associated with higher baseline potassium and log-transformed C-reactive protein and with use of diuretics and potassium binders. Mean serum potassium increased by approximately 0.10 mEq/L over six months, with the largest rise in the first 1–2 months. Patients with eGFR < 30 mL/min/1.73 m² or baseline potassium ≥ 4.5 mEq/L had higher potassium levels throughout follow-up.

Finerenone was generally well tolerated, with modest potassium increases. In our real-world cohort, hyperkalemia occurred in a notable proportion of patients, underscoring the importance of early monitoring, particularly in those with reduced kidney function or elevated baseline potassium.