An eGFR of 155 mL/min/1.73 m² in a White Male Indicates Glomerular Hyperfiltration
An eGFR of 155 mL/min/1.73 m² is significantly elevated and represents glomerular hyperfiltration (GHF), which warrants clinical investigation for underlying pathology rather than reassurance of "excellent kidney function."
Understanding the Context
Normal eGFR values in healthy adults are substantially lower than 155 mL/min/1.73 m². According to meta-analysis data from healthy living kidney donors, mean GFR is approximately 107 mL/min/1.73 m² in young adults and remains constant until age 40, after which it physiologically declines 1. The 95th percentile of eGFR in healthy populations ranges from 94.7 to 146.7 mL/min/1.73 m² 2, meaning your patient's value of 155 exceeds even the upper boundary of normal variation.
Reference intervals for eGFR in healthy volunteers have been established at 63.5-139.2 mL/min/1.73 m² (using Rule's quadratic equation) 3, further confirming that 155 is abnormally elevated.
Clinical Significance of This Finding
Hyperfiltration is Associated with Adverse Outcomes
Glomerular hyperfiltration is not benign. Meta-analysis demonstrates that GHF is significantly associated with:
- Increased all-cause mortality (HR 1.30; 95% CI 1.18-1.42) 2
- Incident albuminuria (HR 1.43; 95% CI 1.05-1.93) 2
- Potential associations with rapid eGFR decline, incident dementia, and non-alcoholic fatty liver disease 2
What Causes Hyperfiltration?
You must investigate for:
- Diabetes mellitus (early diabetic nephropathy classically presents with hyperfiltration)
- Obesity (increased metabolic demand drives glomerular hyperfiltration)
- High protein intake (dietary protein load increases GFR)
- Pregnancy (physiologic hyperfiltration occurs)
- Single kidney or reduced nephron mass (compensatory hyperfiltration)
- Hypertension (early adaptive response)
- Sickle cell disease
Practical Clinical Approach
Immediate Actions:
Verify the measurement: Repeat eGFR and check which equation was used (CKD-EPI 2021 race-free equation is now standard 4)
Assess for measurement error: Consider if the patient has unusually low muscle mass, which could falsely elevate creatinine-based eGFR. If suspected, obtain cystatin C-based eGFR for confirmation 5
Screen for underlying conditions:
- Hemoglobin A1c and fasting glucose (diabetes screening)
- Urinalysis with albumin-to-creatinine ratio (check for albuminuria)
- Blood pressure measurement
- BMI calculation
- Dietary history focusing on protein intake
Monitor longitudinally: A single elevated value requires follow-up. Persistent hyperfiltration (>120 mL/min/1.73 m²) over 3-6 months confirms the diagnosis 2
Important Caveats:
- Do not dismiss this as "super healthy kidneys"—the evidence clearly shows hyperfiltration predicts worse outcomes
- Age matters: While GFR naturally declines with age starting around 40 years 6, 1, hyperfiltration at any age is pathologic
- The current KDIGO classification system (G1-G5) does not specifically address hyperfiltration 7, but this represents a gap in the guidelines rather than evidence that it's unimportant
If Hyperfiltration is Confirmed:
- Address modifiable risk factors (weight loss if obese, glycemic control if diabetic, dietary protein restriction if excessive)
- Establish baseline albuminuria status
- Monitor eGFR trajectory every 6-12 months to detect early decline
- Consider nephrology referral if associated with albuminuria or rapid progression
The key message: An eGFR of 155 mL/min/1.73 m² is abnormal, not optimal, and requires diagnostic evaluation and ongoing monitoring to prevent future kidney disease progression and associated mortality risk.