Normal glomerular-tubular feedback: - Proximal tubule reabsorbs NaCl → reduced delivery to macula densa - Macula densa senses low NaCl → ↓ renin release, ↑ afferent arteriolar vasodilation - Result: Maintains GFR
With SGLT2i: 1. SGLT2 blockade → ↑ Na+ delivery to macula densa (not reabsorbed with glucose) 2. Macula densa senses “high NaCl” → ↑ renin release, afferent arteriolar vasoconstriction 3. Reduces intraglomerular pressure → ↓ GFR initially (expected, not harmful) 4. Net effect: Glomerular pressure drops → proteinuria ↓, sclerosis prevented
eGFR “dip” with SGLT2i: Expect 10-30% initial decline in eGFR within days-weeks. This is expected and reflects pressure reduction, not true renal injury. The dip improves outcomes by preventing glomerulosclerosis.
| Agent | Dose (Nephrology) | Plasma t½ | Renal Clearance | FDA Approval (Renal) |
|---|---|---|---|---|
| Empagliflozin (Jardiance) | 10 mg daily | 13.1 hr | <10% | EMPA-KIDNEY (2022) |
| Dapagliflozin (Farxiga) | 10 mg daily | 12.9 hr | <0.1% | DAPA-CKD (2020) |
| Canagliflozin (Invokana) | 100 mg daily (with caution) | 10.6 hr | 33% renal excretion | CREDENCE (CKD + T2DM) |
Design: T2DM + albuminuria; randomized canagliflozin vs. placebo [1]
Primary outcome: ESRD, doubling Cr, CV death
Results: - 33% ↓ ESRD/doubling Cr (p <0.001) - ↓ CV death (especially HF-related) - Proteinuria ↓ 27% at 30 weeks
Clinical impact: First SGLT2i to show renal benefit; established class effect
Design: CKD stage 3b-4 (eGFR 25-75) + albuminuria; NOT limited to diabetics [2]
Primary outcome: Composite of ≥50% eGFR decline, ESRD, kidney death, CV death, hospitalization for HF
Results: - 39% ↓ composite outcome (p <0.001) - Benefit seen in both diabetic and non-diabetic patients - Dapagliflozin reduced risk across eGFR ranges (even eGFR 25-40) - Proteinuria ↓ 35% by month 2
Clinical impact: Establishes SGLT2i benefit in NON-DIABETIC CKD (IgAN, FSGS, etc.); not just T2DM
Design: CKD stage 2-4 (eGFR >20) + albuminuria; similar broad population [3]
Primary outcome: Kidney disease progression (ESKD, sustained eGFR <10, sustained ≥40% eGFR decline, or renal death) or CV death
Results: - 28% ↓ composite outcome (13.1% vs 16.9%; HR 0.72, 95% CI 0.64–0.82; p <0.001) - Empagliflozin 10 mg also ↓ all-cause hospitalization (HR 0.86, 95% CI 0.78–0.95) - Benefits consistent across diabetes status and eGFR subgroups
Clinical impact: Broadest indication yet; effective even with eGFR 20-30
Design: HFrEF (EMPEROR-Reduced) [5] and HFpEF (EMPEROR-Preserved) [4]
Results: - Empagliflozin 10 mg ↓ CV death + HF hospitalization — 21% in HFpEF (HR 0.79) and 25% in HFrEF (HR 0.75) - Benefit seen in HFpEF (traditionally challenging to treat) - Renal function stable/improved
Clinical impact: Expands SGLT2i use beyond CKD to HF-CKD phenotype
| Outcome | Timeline | Expected Change |
|---|---|---|
| Proteinuria | 2-4 weeks | 30-50% reduction |
| eGFR dip | Days-weeks | 10-30% initial decline (expected; reversible) |
| Stabilization | 6-12 weeks | eGFR stabilizes; trajectory flattened |
| ESRD/doubling Cr | 2-3 years | 25-39% risk reduction |
Expected eGFR dip doesn’t mean kidney damage: The initial 10-30% decline in eGFR within first 4-8 weeks reflects hemodynamic changes (reduced intraglomerular pressure), NOT tubular toxicity. Most stabilize or improve by 12 weeks. Don’t discontinue based on initial dip.
Rare but serious: ~0.1-0.4 cases per 1000 patient-years
Risk factors: - Acute illness (infection, surgery, dehydration) - Insulin-dependent diabetes - Recent change in insulin dosing
Presentation: Normal or mildly elevated glucose (<250 mg/dL) + severe metabolic acidosis (pH <7.25) - Symptoms: Nausea, vomiting, abdominal pain, dyspnea
Prevention: - Counsel patients: Hold SGLT2i during acute illness, surgery, fasting - Monitor for symptoms - Check VBG/ABG if vague abdominal symptoms in diabetic patient on SGLT2i
Treatment: IV insulin, fluid resuscitation, electrolyte correction; restart SGLT2i after recovery if no contraindication
euDKA screening: Any T2DM patient on SGLT2i with nausea/vomiting/abdominal pain → check VBG for acidosis. Can occur at normal glucose levels, making diagnosis challenging.
Frequency: 5-10% (more common in women)
Mechanism: Glucosuria promotes bacterial growth (especially Candida in genital areas)
Management: - Counsel: Hygiene, regular voiding, adequate hydration - Treat infections promptly (antibiotics for UTI, topical/oral antifungals for candida) - Consider discontinuation if recurrent/severe infections
Mechanism: Natriuresis; mainly seen with loop diuretics or severe baseline volume depletion
Risk factors: Concomitant diuretic use, GFR <30, heart failure
Prevention: - Monitor BP standing + sitting - Assess volume status at baseline - Adjust other diuretics if volume depleted (decrease dose)
Management: Usually mild; rehydrate; resume after volume repletion
CANVAS Trial: ↑ lower-extremity amputation risk with canagliflozin (↑ 97% vs. placebo) - Mechanism: Unclear (volume depletion? pressure-related?) - Increased risk: Peripheral arterial disease, prior amputation, foot ulcer history - Management: Canagliflozin use restricted in high-risk patients; preferred agents: dapagliflozin, empagliflozin
SGLT2i benefit independent of baseline glucose control: Even well-controlled T2DM patients gain renal/cardiac benefit. Don’t reserve SGLT2i only for poorly controlled diabetes; use in all CKD + albuminuria if no contraindication.
Initial eGFR dip is EXPECTED and BENEFICIAL: Don’t panic or discontinue SGLT2i if eGFR drops 15-20% in first month. This reflects pressure reduction and is associated with BETTER long-term outcomes. Continue therapy; reassess at 8-12 weeks.
SGLT2i in non-diabetic CKD: DAPA-CKD and EMPA-KIDNEY proved benefit in IgAN, FSGS, lupus, and other non-diabetic kidney diseases. Use SGLT2i in ALL albuminuric CKD, not just diabetes.
Canagliflozin amputation risk: Use dapagliflozin or empagliflozin preferentially in patients with peripheral arterial disease, prior amputation, foot ulcers, or Charcot joint. Risk with canagliflozin outweighs benefits in this population.
SGLT2i + ACE-I/ARB synergy: Combination therapy more effective than either alone for proteinuria reduction. Use together (if no contraindication) for maximal effect.
| Timepoint | Labs/Assessments | Rationale |
|---|---|---|
| Baseline | Cr, eGFR, UACR, K+, glucose, VBG | Baseline safety assessment |
| Week 1-2 | BP standing/sitting | Screen for hypotension |
| 4 weeks | Cr, eGFR, K+ | Monitor eGFR dip; ensure safe |
| 8-12 weeks | Cr, eGFR, proteinuria, symptoms | Assess stabilization; expect eGFR recovery |
| 6-12 months | Cr, eGFR, UACR, K+ | Long-term monitoring |
| Annually | CBC, CMP, UA | Routine surveillance for adverse effects |
[1] CREDENCE Trial (2019): Perkovic V, Jardine MJ, Neal B, et al. Canagliflozin and renal outcomes in type 2 diabetes and nephropathy. N Engl J Med. 2019;380(24):2295–2306. PMID: 30990260
[2] DAPA-CKD Trial (2020): Heerspink HJL, Stefánsson BV, Correa-Rotter R, et al. Dapagliflozin in patients with chronic kidney disease. N Engl J Med. 2020;383(15):1436–1446. PMID: 32970396
[3] EMPA-KIDNEY Trial (results 2022): The EMPA-KIDNEY Collaborative Group; Herrington WG, Staplin N, et al. Empagliflozin in patients with chronic kidney disease. N Engl J Med. 2023;388(2):117–127. PMID: 36331190
[4] EMPEROR-Preserved (2021): Anker SD, Butler J, Filippatos G, et al. Empagliflozin in heart failure with a preserved ejection fraction. N Engl J Med. 2021;385(16):1451–1461. PMID: 34449189
[5] EMPEROR-Reduced (2020): Packer M, Anker SD, Butler J, et al. Cardiovascular and renal outcomes with empagliflozin in heart failure. N Engl J Med. 2020;383(15):1413–1424. PMID: 32865377