Stages of Chronic Kidney Disease and Their Corresponding Treatments
Chronic Kidney Disease (CKD) is classified into five stages based on glomerular filtration rate (GFR) and evidence of kidney damage, with specific treatment approaches for each stage aimed at slowing progression and managing complications.
Definition and Classification of CKD
- CKD is defined as kidney damage or GFR <60 mL/min/1.73 m² persisting for at least 3 months 1
- Kidney damage can be identified through proteinuria, hematuria, structural abnormalities on imaging, or pathological abnormalities 2, 3
- The diagnosis requires abnormalities to be present for at least 3 months to differentiate from acute kidney injury 3
CKD Staging System
Stage 1: GFR ≥90 mL/min/1.73 m² with evidence of kidney damage
- Treatment focuses on diagnosis of underlying cause, CKD risk reduction, and cardiovascular disease prevention 1
- Requires evidence of kidney damage (e.g., proteinuria, structural changes on biopsy) for diagnosis 1, 3
- Clinical action includes screening and addressing modifiable risk factors 1, 4
Stage 2: GFR 60-89 mL/min/1.73 m² with evidence of kidney damage
- Treatment focuses on slowing progression and treating comorbid conditions 1
- Still requires evidence of kidney damage for diagnosis 1, 4
- Clinical action includes estimating progression rate and cardiovascular risk reduction 1, 4
Stage 3: GFR 30-59 mL/min/1.73 m²
- Often subdivided into Stage 3a (GFR 45-59 mL/min/1.73 m²) and Stage 3b (GFR 30-44 mL/min/1.73 m²) 1, 4
- Treatment focuses on evaluating and treating complications 1
- No evidence of kidney damage required at this stage for CKD diagnosis 1, 4
- Complications begin to increase significantly at this stage 1
Stage 4: GFR 15-29 mL/min/1.73 m²
- Treatment focuses on managing complications and preparing for kidney replacement therapy 1
- Referral to nephrologist recommended at this stage 4
- Complications are common, with hypertension prevalence approaching 80% 1
Stage 5: GFR <15 mL/min/1.73 m² or dialysis
- Treatment focuses on kidney replacement therapy (dialysis or transplantation) if uremic symptoms develop 1
- Also known as kidney failure or end-stage renal disease (ESRD) 1
- Requires comprehensive management of uremic complications 1
Clinical Complications by CKD Stage
- Hypertension prevalence increases with declining GFR, approaching 80% in Stage 4 1, 2
- Anemia becomes more prevalent as GFR falls below 60 mL/min/1.73 m² 1, 2
- Nutritional impairment increases with declining GFR 1
- The risk of having multiple complications increases substantially when GFR falls below 30 mL/min/1.73 m² 1, 2
Diagnostic Considerations
- GFR should be estimated using prediction equations that account for serum creatinine concentration, age, sex, race, and body size 1, 2
- The MDRD Study equation and CKD-EPI equations are recommended for adults 2, 5
- Relying solely on serum creatinine can lead to missed diagnoses, especially in elderly patients or those with reduced muscle mass 3, 5
- Albuminuria should be assessed alongside GFR for comprehensive CKD staging 1, 4
Treatment Approaches by Stage
- Stages 1-2: Focus on early detection, risk reduction, and treating underlying conditions 1, 4
- Stage 3: Begin evaluation for complications and implement strategies to slow progression 1, 4
- Stage 4: Intensive management of complications and preparation for kidney replacement therapy 1, 4
- Stage 5: Implement kidney replacement therapy when uremic symptoms develop 1, 4
Important Clinical Considerations
- Even Stage 1 CKD with normal GFR carries increased risk for cardiovascular disease and mortality 3
- Age-related decline in GFR should not be considered "normal aging" as decreased GFR in the elderly remains an independent predictor of adverse outcomes 1, 4
- The combination of GFR and albuminuria provides better risk stratification for disease progression and outcomes 2, 6