What management approach is recommended for an adult patient with elevated eGFR, potentially with a history of conditions like diabetes or hypertension?

Management of Elevated eGFR in Adults

For adults with elevated eGFR (≥90 mL/min/1.73 m²), particularly those with diabetes or hypertension, the primary concern is identifying and managing underlying conditions that drive hyperfiltration, as elevated eGFR is associated with increased mortality risk and often precedes progressive kidney disease. 1

Understanding the Clinical Significance

Elevated eGFR is not benign and requires careful evaluation:

• Mortality risk increases at eGFR ≥90 mL/min/1.73 m², with hazard ratios of 1.8 for eGFR 90-104.9 mL/min/1.73 m² and 3.7 for eGFR ≥105 mL/min/1.73 m², compared to the optimal range of 60-74.9 mL/min/1.73 m² 1
• The presence of proteinuria dramatically amplifies risk at all eGFR levels, including elevated ranges, making concurrent albuminuria assessment mandatory 1
• In diabetic patients, hyperfiltration (elevated eGFR) frequently precedes rapid eGFR decline, particularly when accompanied by HbA1c reductions ≥1.0% 2

Essential Diagnostic Workup

Measure both eGFR and urine albumin-to-creatinine ratio (UACR) simultaneously, as both parameters are required to guide treatment decisions and risk stratification 3:

• Check UACR in first-morning urine to detect early glomerular damage 3
• Assess for secondary causes of hyperfiltration: uncontrolled hyperglycemia, high protein intake (>1.3 g/kg/day), volume expansion, or pregnancy 3
• Verify hypertension control and screen for renovascular disease if blood pressure is difficult to control 4
• In diabetic patients, check for diabetic retinopathy, as its absence in type 1 diabetes suggests alternative kidney pathology requiring nephrology referral 3

Monitoring Frequency Based on Risk Stratification

Follow the KDIGO risk-based monitoring schedule that incorporates both eGFR and albuminuria 3:

• Green zone (normal UACR, eGFR ≥90): Annual measurements 3
• Yellow zone (UACR 30-300 mg/g with eGFR ≥90): At least once yearly 3
• Orange zone (UACR >300 mg/g with eGFR ≥90): Twice yearly 3
• Any patient with rapid eGFR decline (≥5 mL/min/1.73 m² per year): Increase monitoring to every 3-6 months and consider nephrology referral 5

Therapeutic Interventions

Blood Pressure Management

Target systolic blood pressure <130 mmHg for most patients with diabetes and elevated eGFR 3:

• Initiate ACE inhibitor or ARB if UACR ≥30 mg/g (moderately increased albuminuria), regardless of blood pressure, as these agents reduce albuminuria and slow progression 3
• For patients with UACR 30-300 mg/g, start low-dose ACE inhibitor/ARB and titrate to guideline-recommended doses with monitoring of serum creatinine and potassium at 2-4 weeks after initiation 3
• Accept transient eGFR decreases up to 30% from baseline after starting RAS blockade, as this reflects beneficial hemodynamic changes rather than kidney injury 3

Glycemic Management

Optimize glucose control to prevent progression from hyperfiltration to overt kidney disease 3:

• Target HbA1c <7.0% for most patients, with individualization based on hypoglycemia risk and comorbidities 3
• Metformin requires no dose adjustment at eGFR ≥60 mL/min/1.73 m² and is the preferred first-line agent 3
• Add SGLT2 inhibitor if UACR ≥30 mg/g, as these agents provide kidney and cardiovascular protection independent of glycemic effects 3
• Consider GLP-1 receptor agonist with proven cardiovascular benefit (liraglutide, semaglutide, dulaglutide) for additional kidney and cardiovascular protection 3

Dietary Modifications

Restrict dietary protein intake to <0.8 g/kg/day (the recommended daily allowance) to reduce glomerular hyperfiltration 3:

• Avoid high protein intake (>1.3 g/kg/day or >20% of daily calories), as this is associated with increased albuminuria and faster kidney function loss 3
• Limit sodium intake to <2.3 g/day to optimize blood pressure control 3

Lifestyle Interventions

Smoking cessation is mandatory, as smoking history independently predicts rapid eGFR progression (aOR 1.91) 5:

• Provide structured diabetes self-management education addressing diet, exercise, and medication adherence 3
• Encourage regular physical activity while monitoring for exercise-induced proteinuria in high-risk patients 3

When to Refer to Nephrology

Consider nephrology referral for 3:

• Persistent UACR ≥300 mg/g despite optimized RAS blockade 3
• Rapid eGFR decline ≥5 mL/min/1.73 m² per year 3
• Active urinary sediment (red/white blood cells, cellular casts) suggesting glomerulonephritis 3
• Absence of diabetic retinopathy in type 1 diabetes with kidney disease, indicating possible non-diabetic kidney disease 3
• Difficulty achieving blood pressure targets despite multiple agents 3

Common Pitfalls to Avoid

Do not dismiss elevated eGFR as "good kidney function" without assessing for albuminuria and underlying hyperfiltration 1:

• Never delay RAS blockade in patients with albuminuria due to concerns about eGFR decline, as early intervention prevents progression 3
• Avoid excessive protein intake even in patients with normal or elevated eGFR, as this accelerates kidney damage 3
• Do not use glyburide in any patient with diabetes and kidney concerns, as it is contraindicated and increases hypoglycemia risk 3
• Monitor for rapid HbA1c reductions (≥1.0%) in patients with hyperfiltration, as this correlates with subsequent rapid eGFR decline 2
• Ensure adequate health insurance coverage for medications, as partial coverage independently predicts rapid eGFR progression (aOR 1.48) 5