From the Guidelines
Chronic Kidney Disease (CKD) is classified into five stages based on estimated glomerular filtration rate (eGFR), which measures kidney function, with Stage 1 involving normal kidney function (eGFR ≥90 mL/min/1.73m²) and evidence of kidney damage, Stage 2 representing mild kidney damage with slightly reduced function (eGFR 60-89 mL/min/1.73m²), Stage 3 divided into two substages (3a and 3b), Stage 4 showing severe kidney damage (eGFR 15-29 mL/min/1.73m²), and Stage 5 representing kidney failure (eGFR <15 mL/min/1.73m²) or dialysis dependence, as defined by the National Kidney Foundation guidelines 1.
The classification of CKD stages is crucial for determining the severity of kidney damage and for guiding treatment plans. The stages are defined as follows:
- Stage 1: eGFR ≥90 mL/min/1.73m² with evidence of kidney damage
- Stage 2: eGFR 60-89 mL/min/1.73m² with evidence of kidney damage
- Stage 3: divided into two substages:
- 3a: eGFR 45-59 mL/min/1.73m²
- 3b: eGFR 30-44 mL/min/1.73m²
- Stage 4: eGFR 15-29 mL/min/1.73m²
- Stage 5: eGFR <15 mL/min/1.73m² or dialysis dependence
The National Kidney Foundation guidelines emphasize the importance of using eGFR to classify the stage of CKD, as it provides a reliable measure of kidney function 1. The guidelines also highlight the need for regular monitoring of kidney function through blood tests measuring creatinine and urine tests for protein to track disease progression and adjust treatment plans accordingly 1.
Key points to consider when classifying CKD stages include:
- The use of eGFR as the primary measure of kidney function
- The presence of evidence of kidney damage, such as albuminuria or structural abnormalities
- The division of Stage 3 into two substages (3a and 3b) to reflect the progression of kidney damage
- The definition of Stage 5 as kidney failure or dialysis dependence, regardless of the underlying cause of kidney disease
By understanding the different stages of CKD and their corresponding eGFR values, healthcare providers can develop effective treatment plans to slow disease progression and improve patient outcomes 1.
From the Research
Definition and Classification of CKD
The definition and classification of chronic kidney disease (CKD) have evolved over time, but current international guidelines define this condition as decreased kidney function shown by glomerular filtration rate (GFR) of less than 60 mL/min per 1·73 m2, or markers of kidney damage, or both, of at least 3 months duration, regardless of the underlying cause 2.
CKD Stages
CKD is classified into five stages according to the level of GFR 3. The stages are:
- Stage 1: Kidney damage with normal or increased GFR
- Stage 2: Mild decrease in GFR (60-89 mL/min/1.73 m2)
- Stage 3: Moderate decrease in GFR (30-59 mL/min/1.73 m2)
- Stage 4: Severe decrease in GFR (15-29 mL/min/1.73 m2)
- Stage 5: Kidney failure (GFR < 15 mL/min/1.73 m2 or on dialysis)
Management of CKD
The management of CKD involves slowing the progression of kidney damage and reducing the risk of cardiovascular disease 4, 5, 6. Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) are commonly used in patients with early CKD, but their value in advanced CKD is unknown 6.
Key Points
- CKD is a long-term condition that occurs as a result of damage to the kidneys 4.
- Early recognition and management of CKD can help reduce the risk of progression and cardiovascular disease 4.
- The use of ACEi and ARB in advanced CKD is controversial, with some studies suggesting that they may slow the progression of kidney damage, while others argue that they may not be effective in reducing cardiovascular risk 5, 6.