From the Guidelines
A GFR of 64 mL/min/1.73m² indicates a mild reduction in kidney function, but it is still considered within the normal range for many adults, especially older individuals, as normal GFR varies according to age, sex, and body size 1.
Understanding GFR and Kidney Function
The Glomerular Filtration Rate (GFR) is a key indicator of kidney function, measuring how well the kidneys filter blood to remove waste products. A GFR of 64 mL/min/1.73m² suggests that while the kidneys are functioning, their efficiency might be slightly reduced compared to the peak levels seen in younger, healthy adults. However, it's crucial to consider age, sex, and body size when interpreting GFR values, as these factors naturally influence kidney function 1.
Implications of a GFR of 64
Given that a GFR level less than 60 mL/min per 1.73 m² represents a loss of half or more of the adult level of normal kidney function, a GFR of 64 is still above this threshold, indicating that the individual does not have a significant reduction in kidney function according to the guidelines provided by the National Kidney Foundation 1. It's essential for individuals with a GFR of 64 to maintain a healthy lifestyle, including monitoring blood pressure, controlling blood sugar if diabetic, and avoiding substances that could further reduce kidney function.
Management and Monitoring
For someone with a GFR of 64, regular monitoring of kidney function is advisable, typically through follow-up blood tests every 6-12 months. Lifestyle modifications such as maintaining healthy blood pressure, controlling diabetes, following a balanced diet, staying hydrated, and avoiding nephrotoxic substances can help preserve kidney function. Since the GFR of 64 is considered near the lower end of normal for some populations, especially younger individuals, but within normal limits for others, particularly the elderly, personalized advice from a healthcare provider is essential to manage any potential risks associated with reduced kidney function 1.
From the Research
Kidney Function and GFR
- A Glomerular Filtration Rate (GFR) of 64 indicates that the kidney function is close to the normal range, but may be slightly decreased, as normal GFR values are largely over 60 mL/min/1.73 m2 in healthy subjects, at least before the age of 70 years 2.
- However, it's essential to consider the age of the individual, as GFR physiologically decreases with age, and in adults older than 70 years, values below 60 mL/min/1.73 m2 could be considered normal 2.
Factors Affecting GFR
- Certain medications, such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs), can affect GFR, but their impact may vary depending on the individual's condition and the dose of the medication 3, 4, 5, 6.
- ACE inhibitors and ARBs can increase GFR and renal blood flow in patients with hypertension, but may also cause acute deterioration in renal function in some cases 3.
- The use of ACE inhibitors and ARBs in patients with chronic kidney disease (CKD) is a topic of debate, with some studies suggesting that their benefits may outweigh the potential risks, while others recommend careful consideration of their use in advanced CKD 4, 5, 6.
Interpreting GFR Results
- A GFR of 64 may not necessarily indicate kidney disease, but rather a slightly decreased kidney function, which may be a normal part of the aging process 2.
- It's crucial to consider the individual's overall health, medical history, and other factors that may affect kidney function when interpreting GFR results 2, 4, 5, 6.