A mild decrease in Glomerular Filtration Rate (GFR) indicates less efficient kidney function. This early signal is common, especially with age, and requires monitoring and management.
Understanding GFR Levels
GFR, or Glomerular Filtration Rate, measures how well the kidneys are filtering blood. The kidneys contain tiny filters called glomeruli that remove waste and excess water from the blood to produce urine. A GFR test measures how much blood these filters clear each minute. This measurement is typically estimated (eGFR) using a blood test that assesses creatinine levels, a waste product from muscle breakdown, along with factors like age, sex, and body size.
A GFR of 90 mL/min/1.73m² or higher is generally considered normal for healthy adults. A “mild decreased GFR” typically falls within the range of 60 to 89 mL/min/1.73m² and is often categorized as Stage 2 Chronic Kidney Disease (CKD). While this indicates a mild loss of kidney function, kidneys can still work well within this range. A GFR below 60 mL/min/1.73m² for three months or more generally signifies kidney disease.
Identifying Contributing Factors
Several factors and conditions can contribute to a mild decline in GFR. Natural aging is a common cause, as GFR typically decreases with age, even in individuals without kidney disease. Chronic conditions are also significant contributors, with high blood pressure (hypertension) and diabetes being among the most frequent causes of kidney damage. Uncontrolled high blood pressure can damage the blood vessels in the kidneys, impeding their filtering ability. Similarly, consistently elevated blood sugar levels from diabetes can harm the kidneys over time.
Certain medications, such as long-term non-steroidal anti-inflammatory drugs (NSAIDs), can also impact GFR. Less common factors include kidney infections, urinary tract blockages, or inherited kidney diseases like polycystic kidney disease. Obesity, high total cholesterol, and high uric acid levels have also been correlated with a mildly reduced GFR.
Managing Mild GFR Decline
Managing a mild GFR decline often involves lifestyle adjustments to preserve kidney function and slow disease progression. Dietary modifications are a primary focus, including reducing sodium intake to less than 2,300 mg per day to help control blood pressure and fluid retention. A balanced diet rich in fruits, vegetables, and whole grains, while moderating protein intake, can support kidney health. Limiting processed foods, refined carbohydrates, and sugary beverages is also beneficial.
Regular physical activity, such as aiming for at least 150 minutes of exercise per week, assists in maintaining a healthy weight, controlling blood pressure, and managing blood sugar levels. Quitting smoking and limiting alcohol consumption are also important steps, as tobacco use can damage blood vessels and increase blood pressure, while excessive alcohol intake can raise blood pressure and disrupt fluid balance. For individuals with underlying conditions like high blood pressure or diabetes, consistent management of these conditions through medication and lifestyle choices is important to protecting kidney health.
Monitoring and Future Considerations
Ongoing monitoring of GFR levels through regular medical check-ups is important to track any changes in kidney function. Healthcare providers will typically order blood tests to measure eGFR and urine tests to check for albumin, a protein that can indicate kidney damage. A sustained decrease in GFR of 5 mL/min/1.73m² within one year or 10 mL/min/1.73m² within five years may indicate a significant decline.
For many individuals with a mild decreased GFR, the condition can remain stable or progress very slowly, especially with proper management and adherence to lifestyle adjustments. Early detection allows for interventions that can help maintain kidney health and potentially prevent progression to more advanced stages of kidney disease. While GFR naturally declines with age, a low GFR in an older person does not always signify chronic kidney disease, particularly if there are no other signs of kidney damage like albuminuria.