Can You Use MRAs in CKD with Borderline Hyperkalemia?
Finerenone is approved for albuminuric CKD in T2D at eGFR ≥25. The FDA label specifies not initiating if baseline serum potassium is >5.0 mEq/L; FIDELIO/FIGARO used a stricter ≤4.8 enrollment cutoff. Spironolactone and eplerenone are more potent potassium raisers and are typically avoided at eGFR <30 unless hyperkalemia is managed with patiromer, sodium zirconium, or concurrent SGLT2 inhibitor. SGLT2 inhibitor co-therapy lowers hyperkalemia risk and enables MRA use in many otherwise borderline patients.
Evidence review
Pivotal trials, effect sizes, and the populations they studied. PubMed identifiers link directly to the source.
FIDELIO-DKD (2020)
PMID 332648255,734 with T2D and CKD, eGFR 25–75, UACR ≥30
Finerenone reduced composite renal outcome 18% (HR 0.82) and CV composite 14% (HR 0.86). Hyperkalemia discontinuation 2.3% vs 0.9%.
FIGARO-DKD (2021)
PMID 347757847,437 with T2D and CKD, eGFR 25–90
Finerenone reduced CV composite 13% (HR 0.87). Benefit consistent across CKD stages.
FIDELITY pooled analysis (2022)
PMID 3502354713,026 from FIDELIO + FIGARO
With SGLT2 inhibitor, finerenone hyperkalemia incidence was lower. Cardiorenal benefits preserved across subgroups.
Practical decision algorithm
| If | Then |
|---|---|
| T2D + CKD (eGFR 25–75) + UACR ≥30, K+ ≤5.0 (FDA label) | Start finerenone 10 mg daily (20 mg if eGFR ≥60); recheck K+ at 4 weeks. FIDELIO/FIGARO enrolled at K+ ≤4.8 — use that stricter threshold if clinically cautious. |
| K+ 4.8–5.0 at baseline | Start SGLT2 inhibitor first; recheck K+ in 2–4 weeks; then add finerenone if stable. |
| K+ 5.0–5.5 on therapy | Hold MRA; address diet, loop diuretic titration, or add patiromer/sodium zirconium. |
| K+ >5.5 or recurrent >5.0 | Discontinue MRA or continue with K+ binder long-term. |
| HFrEF + CKD + K+ borderline | Prefer spironolactone or eplerenone (mortality benefit) with K+ binder; finerenone lacks HFrEF mortality data. |
Guideline position
KDIGO 2024 CKD guideline: nonsteroidal MRA (finerenone) suggested as add-on to RAS blockade and SGLT2 inhibitor in T2D with eGFR >25, normal K+, and albuminuria >30 mg/g. ADA 2026 Standards of Care: finerenone recommended as add-on in diabetic CKD with persistent albuminuria. 2022 AHA/ACC/HFSA HF guideline: MRA (spironolactone/eplerenone) Class 1 for mortality in HFrEF, continued through mild-moderate hyperkalemia with binders.
Contraindications and cautions
- Baseline K+ >5.0 mEq/L (finerenone — FDA label) or >5.5 (spironolactone)
- eGFR <25 (finerenone) or <30 (spironolactone)
- Concurrent strong CYP3A4 inhibitor (finerenone)
- Addison disease
- Severe hepatic impairment (Child-Pugh C)