How can I preserve my Glomerular Filtration Rate (GFR)?

Preserving Your Glomerular Filtration Rate (GFR)

The most effective strategy to preserve GFR combines four evidence-based interventions: ACE inhibitors or ARBs at maximum tolerated doses, SGLT2 inhibitors (if eGFR ≥20 ml/min/1.73 m²), optimal blood pressure control targeting <120 mmHg systolic, and dietary protein restriction (0.6-0.75 g/kg/day) with adequate caloric intake. 1

Core Pharmacologic Interventions

RAS Inhibition (First-Line Therapy)

ACE inhibitors or ARBs should be initiated and titrated to maximum tolerated doses regardless of blood pressure, as they slow GFR decline through mechanisms beyond blood pressure reduction alone. 1

• Start ACE inhibitors or ARBs even with normal albuminuria if you have hypertension or heart failure, but they are strongly recommended if you have albuminuria ≥30 mg/g 1
• Titrate to maximum approved doses used in clinical trials—this is where the proven benefits were demonstrated 1
• Continue ACE inhibitors/ARBs even as eGFR declines below 30 ml/min/1.73 m², and even down to 20 ml/min/1.73 m² 1, 2
• Accept up to 30% rise in serum creatinine within 4 weeks of initiation—this hemodynamic adjustment predicts better long-term outcomes 1, 2
• Monitor creatinine and potassium within 2-4 weeks after starting or dose increases 1

Critical pitfall: Do not stop ACE inhibitors for modest creatinine rises or mild hyperkalemia—manage hyperkalemia with dietary restriction, diuretics, or potassium binders rather than discontinuing the drug 1, 2

SGLT2 Inhibitors (Essential Addition)

SGLT2 inhibitors provide kidney protection independent of diabetes status and should be added to ACE inhibitors/ARBs. 1

• Initiate if eGFR ≥20 ml/min/1.73 m² with albuminuria ≥200 mg/g, or if you have heart failure regardless of albuminuria level 1
• Consider even with eGFR 20-45 ml/min/1.73 m² and albuminuria <200 mg/g 1
• Once started, continue even if eGFR falls below 20 ml/min/1.73 m² unless dialysis is initiated 1
• The initial reversible eGFR decrease does not require stopping therapy 1
• Temporarily withhold during prolonged fasting, surgery, or critical illness to reduce ketosis risk 1

Nonsteroidal Mineralocorticoid Receptor Antagonists

For type 2 diabetes with persistent albuminuria >30 mg/g despite maximum RAS inhibition and SGLT2 inhibitors, add a nonsteroidal MRA (like finerenone) if eGFR >25 ml/min/1.73 m² and potassium is normal. 1

• This represents triple therapy for high-risk patients with persistent albuminuria 1
• Select patients with consistently normal potassium levels and monitor potassium regularly 1
• Manage hyperkalemia medically rather than stopping the drug when possible 1

Blood Pressure Management

Target systolic blood pressure <120 mmHg using standardized office measurement, as blood pressure control slows GFR decline independent of medication class. 1

• Blood pressure lowering slows kidney function loss even without RAS modulators, though ACE inhibitors/ARBs provide additional benefit beyond blood pressure reduction 1
• Reduce blood pressure variability, as fluctuations independently predict kidney injury 1
• Use ACE inhibitors or ARBs as first-line agents for both blood pressure and proteinuria control 1

Dietary Interventions

Protein Restriction

Reduce dietary protein to 0.6-0.75 g/kg/day when eGFR falls below 50 ml/min/1.73 m², as this slows progression without causing malnutrition if energy intake is adequate. 1

• Target 0.6 g protein/kg/day for optimal GFR preservation, or up to 0.75 g/kg/day if adherence is difficult 1
• Must be combined with adequate energy intake of 35 kcal/kg/day (age <60 years) or 30-35 kcal/kg/day (age ≥60 years) to prevent malnutrition 1
• Consider ketoanalogue supplementation (1 tablet per 5 kg body weight) when implementing very low protein diets (0.3-0.4 g/kg/day) in CKD stages 3b-4 to maintain nutritional status while delaying dialysis 3
• Requires expert dietary supervision and careful monitoring of nutritional parameters 1

Sodium Restriction

Limit dietary sodium intake, as sodium restriction enhances the effectiveness of RAS inhibitors and reduces proteinuria. 1

• Sodium restriction works synergistically with ACE inhibitors/ARBs for blood pressure and proteinuria control 1
• Particularly important in nephrotic syndrome and proteinuric kidney disease 1

Glycemic Control (If Diabetic)

Optimize glucose control to reduce risk of GFR decline, with individualized A1C targets. 1

• Add GLP-1 receptor agonists if glycemic targets not met with metformin and SGLT2 inhibitors 1
• Prioritize agents with proven cardiovascular and kidney benefits 1

Monitoring Strategy

Monitor eGFR and albuminuria at frequencies determined by CKD stage: 1

• Stage 1-2 (eGFR ≥60): Annually
• Stage 3a (eGFR 45-59): 1-2 times yearly
• Stage 3b (eGFR 30-44): 2 times yearly
• Stage 4 (eGFR 15-29): 3 times yearly
• Stage 5 (eGFR <15): 4 times yearly

Monitor nutritional status (BMI, albumin) every 3 months if on protein restriction. 3

Critical Contraindications and Cautions

Screen for bilateral renal artery stenosis before starting ACE inhibitors/ARBs, as this represents an absolute contraindication where GFR becomes entirely angiotensin II-dependent. 2, 4

• Hold ACE inhibitors/ARBs during volume depletion (vomiting, diarrhea, reduced oral intake) to prevent acute kidney injury 2, 4
• Never combine ACE inhibitors with ARBs or direct renin inhibitors—this is explicitly contraindicated 1
• Avoid nephrotoxic agents including NSAIDs, which accelerate GFR decline 1

Preserving Residual Kidney Function on Dialysis

If you progress to dialysis, the same principles apply—continue ACE inhibitors/ARBs to preserve residual kidney function, as this strongly predicts survival. 1

• Residual kidney function preservation should be a major objective even on dialysis 1
• The survival benefit of preserved kidney function shows no plateau effect, unlike dialytic clearance 1
• ACE inhibitors and ARBs slow the decline of residual kidney function in peritoneal dialysis patients 1