GFR of 73: Kidney Function Assessment and Management
What This GFR Means
A GFR of 73 mL/min/1.73 m² represents mildly reduced kidney function that falls within the normal range for most adults and does not indicate chronic kidney disease unless other markers of kidney damage are present. 1
- This GFR is classified as G2 (60-89 mL/min/1.73 m²) according to KDIGO criteria, indicating mildly decreased GFR 1
- This level does not meet diagnostic criteria for CKD unless accompanied by albuminuria, abnormal urine sediment, or structural kidney abnormalities 1
- The risk of progression to end-stage renal disease is low at this GFR level, particularly without albuminuria 1
Clinical Significance and Risk Profile
- A GFR of 73 mL/min/1.73 m² alone, without other kidney damage markers, is not associated with significantly increased risks for adverse outcomes 1
- However, recent evidence shows that even mildly decreased GFR (45-59 mL/min/1.73 m²) in older populations carries increased cardiovascular and mortality risk, so monitoring remains important 2
- The vast majority of patients with stage 3 CKD die from cardiovascular causes rather than progressing to kidney failure 3
Recommended Management Approach
Monitoring Strategy
Annual monitoring is appropriate for this GFR level without albuminuria: 1
- Measure serum creatinine and calculate eGFR annually 1
- Check urine albumin-to-creatinine ratio (ACR) to assess for proteinuria 1
- Monitor blood pressure at each clinical encounter 1
Blood Pressure Management
Target blood pressure of ≤140/90 mmHg regardless of diabetes or proteinuria status 3, 1
- This represents the Canadian Society of Nephrology's recommendation, which differs from more aggressive targets in some guidelines 3
- Cardiovascular risk reduction should be the primary focus at this GFR level 3
Lifestyle Modifications
Implement the following preventive strategies: 1
- Moderate sodium restriction (reduce intake if currently >3.3 g/day, but routine restriction to <2 g/day is not recommended) 3
- Regular physical activity 1
- Smoking cessation if applicable 1
- Weight management to achieve healthy BMI 1
- Avoid routine protein restriction at this GFR level 3
Medication Safety
Exercise caution with nephrotoxic medications: 3
- Adjust doses of renally excreted drugs based on GFR 3
- Metformin can be safely continued at GFR ≥45 mL/min/1.73 m² 3
- Temporarily discontinue ACE inhibitors, ARBs, NSAIDs, and diuretics during acute illnesses that increase AKI risk 3
- Avoid herbal remedies 3
- Seek medical or pharmacist advice before using over-the-counter medicines 3
When Nephrology Referral Is NOT Needed
Nephrology referral is generally not necessary at GFR 73 mL/min/1.73 m² unless: 3, 1
- Proteinuria exceeds 1 g/day (ACR ≥60 mg/mmol or PCR ≥100 mg/mmol) 3
- There is an abrupt sustained decrease in eGFR >20% after excluding reversible causes 3
- GFR falls below 30 mL/min/1.73 m² 3
- Hypertension becomes refractory to 4 or more antihypertensive agents 3
- Evidence of rapid progression develops 3
Important Caveats
Accuracy Considerations
Be aware that eGFR calculations may be inaccurate in certain situations: 1
- Extremes of muscle mass (very high or very low) 1
- Extremes of body weight 1
- Non-steady state conditions (acute kidney injury) 1
- Advanced age (though decreased GFR remains an independent predictor of adverse outcomes in elderly) 4
Context Matters
- Normal eGFR values in healthy adults can range from 63.5-124.6 mL/min/1.73 m² depending on the equation used 5
- A GFR >60 mL/min/1.73 m² does not exclude kidney disease if other markers of damage are present 5
- Age-related decline in GFR typically begins after age 40 years, with mean GFR around 107 mL/min/1.73 m² in younger adults 6