CKD-EPI: normal, low level, kidney disease?

What is glomerular filtration rate?

“The glomerular filtration rate (or GFR) corresponds to to the volume of blood filtered by the kidneys in one minute, explains Dr Hélène Schwaller, medical biologist. It is generally assessed from creatinine dosage in the blood according to different mathematical formulas“. GFR is an important indicator of kidney function. A decrease in it may indicate renal failure (chronic or acute). “GFR measurement is often used in combination with other tests (such as urine albumin and creatinine) to assess kidney function and diagnose kidney disease.“.

What is CKD-EPI?

CKD-EPI is the abbreviation of “Chronic Kidney Disease Epidemiology Collaboration”. The result is expressed in milliliters per minute per 1.73 square meters of body surface area (mL/min/1.73 m²). “This is a mathematical formula used to estimate the glomerular filtration rate (GFR) from blood creatinine measurement, age and sex of the patient“, continues the biologist. The use of this formula is recommended by the High Authority of Health (HAS) for the diagnosis and monitoring of chronic renal failure. “The CKD-EPI formula was developed to improve the accuracy of GFR estimation, particularly in people with normal or mildly impaired kidney function“.”There are other formulas older than the CKD-EPI to estimate the glomerular filtration rate (GFR), such as the MDRD (Modification of Diet in Renal Disease) or CG (Cockroft and Gault), adds Dr. Schwaller. But these are no longer recommended for the diagnosis and monitoring of kidney disease“.

Normal GFR values

There is no DFG”normal“unique, because the result varies depending on the individual. “Nevertheless, thee normal CKD-EPI is greater than 90 mL/min/1.73m², between 60 and 90 it is said to be “slightly diminished” and less than 60 mL/min/1.73 m² it is suggestive of renal failure (chronic or acute)“. Note that the DFG decreases physiologically after 40 years (decrease of less than 2mL/min/1.73m² per year).

CKD-EPI low: why? what to do ?

“A DFG less than 60 mL/min/1.73 m² (or between 60 and 89 with other signs of kidney damage) is suggestive of kidney disease, underlines our interlocutor. This reduction can be acute or chronic“. We are talking about chronic kidney disease when one of the signs of kidney damage (decrease in GFR and/or other sign(s) such as the presence of proteins in the urine) persists for more than 3 months: it affects almost 6 million patients in France. “If the GFR/CKD-EPI is low, it is important to determine the underlying cause and treat any disease or other factors that contribute to decreased kidney function. Additional tests, such as blood and urine tests, may be needed“.

Long silent kidney symptoms

“There are two main causes of chronic kidney disease : diabetes and high blood pressure (hypertension), observes the biologist. But other factors exist: “nephrotoxic” drug treatments, cardiovascular diseases, several episodes of acute renal failure…”. The decrease in renal filtration is silent. “Symptoms will only be present in the advanced stages of the disease: it is therefore essential to fcarry out targeted screening of the population at risk (diabetes, hypertension, obesity, cardiovascular disease, etc.)”.
In some cases, lifestyle changes, such as diet modification, weight loss, and exercise, can help slow the progression of kidney disease. “In other cases, medications may be prescribed to help control blood pressure and/or diabetes and slow the progression of kidney disease.“.

Thanks to Dr Hélène Schwaller, medical biologist at the B2A Laboratory in Épinal and member of the Independent Biologists network.