Chronic Kidney Disease
Definition
Chronic kidney disease (CKD) is defined by structural or functional kidney abnormalities persisting ≥3 months, characterized by reduced estimated glomerular filtration rate (eGFR <60 ml/min/1.73m²) and/or markers of kidney damage (albuminuria ≥30 mg/g, hematuria, structural abnormalities). CKD affects approximately 800 million adults globally (2023), more than doubling since 1990. While type 2 diabetes is the most common single cause, more than half of all CKD cases occur in persons without diabetes. CKD is a major independent risk factor for cardiovascular disease, with cardiovascular mortality exceeding the risk of progression to end-stage kidney disease (ESKD). sources/Finerenone-FIND-CKD-NEJM-2026 — very high
Key Concepts
Epidemiology and Prognosis
- ~800 million adults affected globally in 2023; prevalence has more than doubled since 1990. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- Type 2 diabetes is the most common cause, but >50% of cases are in persons without diabetes. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- Progressive loss of kidney function and adverse cardiovascular outcomes occur in many persons with CKD despite guideline-recommended therapy, particularly those with severely increased albuminuria. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- Cardiovascular disease is the leading cause of death in CKD; the risk of CV death exceeds the risk of progressing to ESKD at most stages.
Pathophysiology
- Mineralocorticoid receptor overactivation: Implicated in CKD progression through increased sodium and fluid retention and activation of proinflammatory and profibrotic processes. This pathway is independent of aldosterone levels — cortisol can also activate the MR in states of tissue damage and oxidative stress. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- Glomerular hyperfiltration: Compensatory hyperfiltration in remaining nephrons leads to progressive glomerulosclerosis, proteinuria, and further nephron loss.
- Tubulointerstitial fibrosis: Final common pathway of all progressive CKD, regardless of etiology.
KDIGO 2024 Guideline-Directed Medical Therapy
- RAS inhibitors (ACEi/ARB): Established first-line therapy; reduce proteinuria and slow eGFR decline by 0.5–1.0 ml/min/1.73m²/year. Renoprotective in both diabetic and non-diabetic CKD. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- SGLT2 inhibitors: Class I recommendation; slow eGFR decline; reduce ESKD and CV death. Benefit across diabetic/non-diabetic CKD, all eGFR strata ≥20, and all albuminuria categories (see concepts/SGLT2-Inhibitors-in-CKD). sources/dapagliflozin-dapackd-nejm-2020 — very high; sources/empagliflozin-empakidney-nejm-2025 — very high
- Nonsteroidal MRA (finerenone): FIND-CKD (NEJM 2026) establishes finerenone as the third pillar of CKD pharmacotherapy — slows eGFR decline by 0.7 ml/min/1.73m²/year and reduces kidney/CV events (HR 0.77; P=0.04) in non-diabetic CKD. Previously established in diabetic CKD (FIDELIO-DKD, FIGARO-DKD). (See entities/Finerenone). sources/Finerenone-FIND-CKD-NEJM-2026 — very high
eGFR Slope as a Surrogate Endpoint
- eGFR slope (annual rate of change) is increasingly used as a primary endpoint in CKD trials.
- A meta-analysis of 66 RCTs found that a 0.75 ml/min/1.73m² attenuation of eGFR decline predicted a 23% reduction in adverse kidney outcomes. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- The two-slope model (acute effect up to month 3 + chronic slope thereafter) separates the initial hemodynamic effect from the disease-modifying effect on kidney function decline.
- Finerenone causes an acute eGFR increase (opposite to SGLT2i acute dip), attributed to reduced intraglomerular pressure through efferent arteriole dilation — the total eGFR slope may therefore underestimate the true chronic benefit.
Albuminuria as a Therapeutic Target and Surrogate
- Albuminuria (UACR) is both a marker of kidney damage and an independent risk factor for CKD progression and CV events.
- Finerenone reduced UACR by 41.3% vs 9.1% at 6 months (relative reduction 35.4%); 56.0% achieved ≥30% UACR reduction with finerenone vs 24.4% with placebo (OR 3.99). sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- Early UACR reduction is a validated surrogate for long-term kidney outcomes.
Hyperkalemia Management in CKD Patients on RAAS + MRA
- Hyperkalemia is the principal adverse effect of dual RAS + MRA blockade.
- FIND-CKD: any hyperkalemia 17.0% finerenone vs 13.3% placebo; K⁺ >5.5 in 18.8% vs 12.2%; K⁺ >6.0 in 4.3% vs 2.3%.
- Serious hyperkalemia events (<1% hospitalization, 1.5% vs 0.1% permanent discontinuation, no fatal events). sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- Protocol-mandated K⁺ monitoring and dose adjustment algorithm successfully prevented serious outcomes.
- In contrast, BARACK-D trial: >50% of CKD patients discontinued spironolactone (steroidal MRA) within 6 months, primarily due to safety criteria including hyperkalemia — finerenone's tolerability profile appears superior to steroidal MRAs in CKD. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
Non-Diabetic CKD — Specific Considerations
- Causes: Hypertension/nephrosclerosis, chronic glomerulonephritis (IgA nephropathy, FSGS, membranous), tubulointerstitial disease, autosomal dominant polycystic kidney disease (ADPKD), lupus nephritis, ANCA-associated vasculitis, and other rare diseases.
- FIND-CKD population: Patients with ADPKD, lupus nephritis, and ANCA vasculitis were EXCLUDED; the trial population mainly represents hypertensive/glomerular CKD. Efficacy in excluded etiologies is unknown.
- Evidence base historically smaller than diabetic CKD: RAS inhibitors (landmark trials including AASK, REIN) and SGLT2i (DAPA-CKD 32.5% non-diabetic; EMPA-KIDNEY) established efficacy before FIND-CKD.
Three-Pillar Pharmacotherapy for Non-Diabetic CKD
| Pillar | Drug Class | Evidence | eGFR Benefit |
|---|---|---|---|
| 1st | RAS inhibitor (ACEi/ARB) | Multiple RCTs since 1990s | ~0.5–1.0 ml/min/1.73m²/yr slower decline |
| 2nd | SGLT2 inhibitor | DAPA-CKD (2020), EMPA-KIDNEY (2023) | ~1.0–2.0 ml/min/1.73m²/yr slower decline |
| 3rd | Nonsteroidal MRA (finerenone) | FIND-CKD (2026) | ~0.7 ml/min/1.73m²/yr slower decline |
- All three classes have shown benefit in both diabetic and non-diabetic CKD.
- Whether triple therapy (RASi + SGLT2i + finerenone) provides additive benefit over dual therapy is plausible but not yet proven in a dedicated RCT.
Contradictions / Open Questions
- eGFR slope vs clinical outcomes: FIND-CKD primary endpoint (eGFR slope) was positive while the kidney composite narrowly missed significance (P=0.06). This reflects the trial being powered for the more sensitive eGFR slope endpoint, not clinical events. Whether the 0.7 ml/min/1.73m²/year eGFR benefit will translate into clinically meaningful reductions in ESKD over longer follow-up remains to be confirmed. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- Finerenone vs steroidal MRAs in non-diabetic CKD: No head-to-head comparison exists. BARACK-D data suggest steroidal MRAs (spironolactone) are poorly tolerated in CKD, but efficacy relative to finerenone cannot be inferred from cross-trial comparisons. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- Triple therapy (RASi + SGLT2i + finerenone): Only 17% of FIND-CKD participants were on SGLT2i at baseline. The hypothesis that finerenone provides additive benefit on top of SGLT2i + RASi dual therapy is plausible based on complementary mechanisms (hemodynamic + metabolic + anti-fibrotic) but was not directly tested. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- Generalizability to all CKD etiologies: ADPKD, lupus nephritis, and ANCA vasculitis were excluded. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- Hyperkalemia risk in real-world practice: FIND-CKD had protocol-directed monitoring and dose adjustment. Real-world hyperkalemia rates with less intensive monitoring could be higher, particularly in patients with lower eGFR or higher baseline K⁺. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- CV outcomes underpowered: CV composite HR 0.60 (95% CI 0.27–1.33) is directionally favorable but non-significant. A larger/longer trial is needed to establish CV benefit in non-diabetic CKD. sources/Finerenone-FIND-CKD-NEJM-2026 — very high
- CKD in HFpEF vs CKD without HF: Finerenone reduced kidney events in CKD trials (FIDELIO-DKD, FIGARO-DKD, FIND-CKD) but the kidney composite was numerically worse in FINEARTS-HF (HR 1.33) — the nephroprotective effect may be albuminuria/CKD-dependent and absent in HFpEF patients with low-level albuminuria. See entities/Finerenone for full discussion. sources/finerenone-hfpef-fineartshf-nejm-2024 — very high
Connections
- Related to entities/Finerenone — third pillar of CKD pharmacotherapy
- Related to concepts/SGLT2-Inhibitors-in-CKD — second pillar; complementary mechanism (hemodynamic vs anti-fibrotic)
- Related to concepts/Mineralocorticoid-Receptor-Antagonists-Post-MI — broader MRA evidence framework
- Related to concepts/Cardiorenal-Syndrome — bidirectional HF-CKD interaction
- Related to concepts/Aldosterone-Synthase-Inhibitors — alternative aldosterone pathway strategy
- Related to entities/HFpEF — CKD is a common comorbidity in HFpEF