eGFR 30 is Stage 3B CKD
An eGFR of 30 mL/min/1.73 m² corresponds to Stage 3B chronic kidney disease, defined as moderate to severe GFR decrease with eGFR range of 30-44 mL/min/1.73 m² 1.
CKD Staging Framework
The standardized CKD classification system divides kidney disease into 5 stages based on eGFR:
- Stage 1: eGFR ≥90 mL/min/1.73 m² (with evidence of kidney damage)
- Stage 2: eGFR 60-89 mL/min/1.73 m² (with evidence of kidney damage)
- Stage 3A: eGFR 45-59 mL/min/1.73 m² (mild to moderate decrease)
- Stage 3B: eGFR 30-44 mL/min/1.73 m² (moderate to severe decrease)
- Stage 4: eGFR 15-29 mL/min/1.73 m² (severe decrease)
- Stage 5: eGFR <15 mL/min/1.73 m² or on dialysis (kidney failure)
An eGFR of exactly 30 mL/min/1.73 m² sits at the lower boundary of Stage 3B 1, 2, 3.
Clinical Significance of Stage 3B
Stage 3B represents a critical threshold requiring intensified monitoring and nephrology referral 2, 3. This stage carries substantially higher risk compared to Stage 3A:
- Progression risk: Stage 3B patients have approximately 3-fold higher risk of progression to advanced CKD compared to Stage 3A (HR 2.99,95% CI 2.19-4.10, p<0.001) 4
- Cardiovascular risk: Marked elevation in cardiovascular morbidity and mortality
- Renal replacement consideration: Guidelines recommend considering dialysis therapy and transplantation when eGFR falls below 30 mL/min/1.73 m² 1
Management Implications at This Stage
Patients with eGFR of 30 mL/min/1.73 m² require nephrology referral and monitoring 3 times per year 2, 5. Key management priorities include:
Pharmacologic Interventions
- ACE inhibitors or ARBs for patients with diabetes, hypertension, or albuminuria 1
- Protein restriction to approximately 0.8 g/kg/day 1
- Blood pressure target <130/80 mmHg 3
- Medication dose adjustments based on reduced renal clearance 6
Common Pitfall
Do not confuse an eGFR of 30 with Stage 3 CKD generally—Stage 3 is subdivided into 3A (45-59) and 3B (30-44), and this distinction has major prognostic and management implications. An eGFR of 30 specifically indicates Stage 3B, which requires more aggressive intervention and closer monitoring than Stage 3A 1, 2, 3, 4.