eGFR, or estimated glomerular filtration rate, is a measure of how much blood the kidneys can filter per minute. It is a crucial indicator of kidney function and is commonly used to assess and monitor kidney health.
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eGFR is calculated using a formula that takes into account a person's age, sex, race, and serum creatinine levels.
A lower eGFR value indicates decreased kidney function, with values below 60 mL/min/1.73m^2 considered indicative of chronic kidney disease.
Drugs that affect the renin-angiotensin-aldosterone system, such as ACE inhibitors and ARBs, can impact eGFR and require close monitoring.
SGLT2 inhibitors have been shown to reduce the risk of kidney function decline and may improve eGFR in patients with type 2 diabetes.
Metformin, a common oral antidiabetic drug, is contraindicated in patients with severely reduced eGFR due to the increased risk of lactic acidosis.
Review Questions
Explain how eGFR is used to assess and monitor kidney function.
eGFR is a widely used metric to evaluate kidney health. It provides an estimate of the glomerular filtration rate, which represents the volume of fluid filtered by the kidneys per minute. A decreased eGFR value, typically below 60 mL/min/1.73m^2, indicates reduced kidney function and the presence of chronic kidney disease. Healthcare providers use eGFR to diagnose, stage, and monitor the progression of kidney disease, as well as to guide treatment decisions, such as medication dosing adjustments.
Describe the impact of drugs affecting the renin-angiotensin-aldosterone system and SGLT2 inhibitors on eGFR.
Medications that target the renin-angiotensin-aldosterone system, such as ACE inhibitors and ARBs, can influence eGFR. These drugs may cause a transient decrease in eGFR, which is often a desired effect as it indicates reduced intraglomerular pressure and can help slow the progression of kidney disease. However, close monitoring of eGFR is necessary to ensure the decrease is not excessive. Conversely, SGLT2 inhibitors have been shown to improve eGFR and reduce the risk of kidney function decline in patients with type 2 diabetes, making them a valuable treatment option for this population.
Analyze the considerations regarding the use of metformin in patients with reduced eGFR.
Metformin, a common oral antidiabetic drug, is generally contraindicated in patients with severely reduced eGFR, typically below 30 mL/min/1.73m^2. This is due to the increased risk of lactic acidosis, a potentially life-threatening condition, in individuals with impaired kidney function. Metformin is primarily eliminated through the kidneys, and its accumulation in the body can occur when eGFR is significantly decreased. Healthcare providers must carefully evaluate a patient's eGFR before initiating metformin therapy and monitor eGFR regularly to ensure the continued safe use of the medication. In cases of moderate to severe kidney dysfunction, alternative antidiabetic agents may be more appropriate.
The rate at which the kidneys filter blood, measured in milliliters per minute (mL/min). GFR is considered the best overall indicator of kidney function.
Chronic Kidney Disease (CKD): A condition characterized by a gradual loss of kidney function over time, often leading to the need for dialysis or a kidney transplant.