Chronic kidney disease (CKD) is characterized by a progressive loss of kidney function over time. The progression of CKD is typically categorized into five stages based on the estimated glomerular filtration rate (eGFR). The eGFR, often calculated using serum creatinine levels along with patient’s age, sex, and race, provides an estimate of how well the kidneys are filtering waste products from the blood.
Here are the five stages of CKD:
- Stage 1 (eGFR ≥ 90 mL/min/1.73 m^2)
- Kidney damage with normal or increased eGFR.
- Kidney damage is usually determined by the presence of albuminuria, abnormal urine sediment, electrolyte and other imbalances, or abnormalities in imaging tests.
- Stage 2 (eGFR 60-89 mL/min/1.73 m^2)
- Kidney damage with mildly decreased eGFR.
- Again, evidence of kidney damage is necessary to diagnose CKD at this stage.
- Stage 3 (eGFR 30-59 mL/min/1.73 m^2)
- Moderately decreased eGFR.
- This stage is further divided into two sub-stages:
- 3a: eGFR 45-59 mL/min/1.73 m^2
- 3b: eGFR 30-44 mL/min/1.73 m^2
- Many patients start to manifest clinical symptoms related to reduced kidney function at this stage.
- Stage 4 (eGFR 15-29 mL/min/1.73 m^2)
- Severely decreased eGFR.
- This stage is a preparation phase for end-stage renal disease (ESRD), and discussions about renal replacement therapy (like dialysis or transplantation) usually begin.
- Stage 5 (eGFR < 15 mL/min/1.73 m^2 or on dialysis)
- Also referred to as end-stage renal disease (ESRD) or kidney failure.
- At this stage, the kidneys have almost stopped functioning, and renal replacement therapy (dialysis or kidney transplantation) is necessary for survival.
Managing CKD involves addressing the underlying cause (if known), slowing the progression of the disease, treating complications, and planning for possible kidney replacement therapies. Regular monitoring of eGFR, urinary protein levels, blood pressure, and other relevant parameters is essential for all patients with CKD