What does an estimated Glomerular Filtration Rate (eGFR) of 35 indicate and how is it managed?

eGFR of 35: Stage 3b Chronic Kidney Disease

An eGFR of 35 mL/min/1.73 m² indicates Stage 3b chronic kidney disease (G3b), requiring immediate evaluation for CKD complications, nephrology referral consideration, and aggressive implementation of kidney-protective therapies to prevent progression to end-stage renal disease. 1

Disease Classification and Prognosis

• An eGFR of 35 mL/min/1.73 m² falls within the G3b category (30-44 mL/min/1.73 m²), representing moderately to severely decreased kidney function 1
• This level of kidney function carries significant risk for progression to ESRD and increased cardiovascular mortality 2
• Patients at this stage should be monitored twice annually with both eGFR and urinary albumin measurements to guide therapy 1
• The 10-year risk of ESRD varies dramatically based on rate of decline: a 30% decline in eGFR over 2 years confers a 64% risk of ESRD, while stable eGFR carries only an 18% risk 2

Immediate Evaluation Requirements

Assess for CKD complications that emerge when eGFR falls below 60 mL/min/1.73 m²: 1

• Measure serum potassium, calcium, phosphorus, parathyroid hormone, and hemoglobin
• Evaluate for metabolic acidosis (serum bicarbonate)
• Screen for bone mineral disease
• Assess nutritional status and consider dietary protein restriction

Determine the underlying cause through: 1

• Review of clinical context, personal and family history
• Urinalysis with microscopy and quantitative albuminuria (spot urine albumin-to-creatinine ratio)
• Renal ultrasound to assess kidney size and rule out obstruction
• Consider kidney biopsy if etiology is uncertain or if it would change management 1

Nephrology Referral

Refer promptly to nephrology when eGFR is <30 mL/min/1.73 m² for evaluation of renal replacement therapy 1

• At eGFR of 35, referral is warranted if there is: 1
  • Uncertainty about kidney disease etiology
  • Rapidly progressing kidney disease (>30% decline in eGFR over 2 years)
  • Difficult management issues (refractory hypertension, persistent hyperkalemia)
  • Urinary albumin ≥300 mg/g creatinine

Kidney-Protective Medical Therapy

For Patients with Diabetes and CKD:

First-line therapy: SGLT2 inhibitor + Metformin 1

• SGLT2 inhibitors are strongly recommended for patients with type 2 diabetes, eGFR ≥30 mL/min/1.73 m², and urinary albumin ≥200 mg/g to reduce CKD progression and cardiovascular events 1
• SGLT2 inhibitors can be initiated at eGFR ≥30 and continued through Stage 4-5 CKD until dialysis initiation 1
• Metformin is recommended for eGFR ≥30 mL/min/1.73 m² 1
• If glycemic targets are not met, add a long-acting GLP-1 receptor agonist 1

Nonsteroidal mineralocorticoid receptor antagonist (finerenone) is recommended for patients with diabetes, CKD, and eGFR <60 mL/min/1.73 m² who are at increased cardiovascular risk or unable to use SGLT2 inhibitors 1

RAS Blockade (ACE Inhibitors or ARBs):

Continue or initiate ACE inhibitor or ARB for patients with: 1

• Urinary albumin ≥300 mg/g creatinine (strongly recommended) 1
• Urinary albumin 30-299 mg/g creatinine (recommended) 1
• Use maximally tolerated doses as demonstrated in clinical trials showing efficacy 1
• Do not discontinue for serum creatinine increases ≤30% in the absence of volume depletion 1
• Benefits on mortality and slowed CKD progression are demonstrated even with eGFR <30 mL/min/1.73 m² 1

Monitor serum potassium periodically in patients on ACE inhibitors, ARBs, or mineralocorticoid receptor antagonists with eGFR <60 mL/min/1.73 m² 1

Blood Pressure Management:

• Optimize blood pressure control to reduce CKD progression risk 1
• Target systolic BP <120 mmHg may be appropriate for most patients, though this should be individualized based on patient values regarding intensive BP control 1
• Intensive BP lowering with up to 30% increase in serum creatinine does not increase mortality or progressive kidney disease 1

Additional Interventions:

Lifestyle modifications: 1

• Smoking cessation
• Moderate-intensity physical activity for ≥150 minutes per week 1
• Dietary protein restriction to maximum 0.8 g/kg/day for non-dialysis Stage 3 or higher CKD 1

Statin therapy for cardiovascular risk reduction 1

Treat metabolic acidosis if present 1

Target urinary albumin reduction ≥30% from baseline, as this is associated with improved renal and cardiovascular outcomes 1

Medication Management

• Verify appropriate medication dosing for eGFR <60 mL/min/1.73 m² 1
• Minimize exposure to nephrotoxins: avoid NSAIDs and limit iodinated contrast 1
• Avoid medications that adversely affect CKD patients: most calcium channel blockers (except amlodipine), thiazolidinediones 1

Common Pitfalls

• Do not stop ACE inhibitors/ARBs for minor creatinine increases (<30%) - this is an expected hemodynamic effect, not acute kidney injury 1
• Do not underdose RAS blockers - maximally tolerated doses are required for kidney protection 1
• Do not delay SGLT2 inhibitor initiation in diabetic patients - benefits are substantial for both kidney and cardiovascular outcomes 1
• Do not assume high eGFR is always protective - very high eGFR (>105 mL/min/1.73 m²) with proteinuria may indicate hyperfiltration and increased mortality risk 3