What is Grade II Chronic Kidney Disease (CKD)?

What is Grade II Chronic Kidney Disease (CKD)?

Grade II (Stage 2) CKD is defined as mildly decreased kidney function with a GFR of 60-89 mL/min/1.73 m² PLUS evidence of kidney damage (such as albuminuria ≥30 mg/g, structural abnormalities, or other markers of kidney damage) persisting for at least 3 months. 1

Critical Diagnostic Requirements

The GFR value alone is insufficient to diagnose Stage 2 CKD - you must document kidney damage in addition to the mildly decreased GFR. 2, 3 This is a common diagnostic pitfall that leads to overdiagnosis.

Evidence of kidney damage includes:

• Albuminuria with UACR ≥30 mg/g (most common marker) 1
• Structural abnormalities on imaging (reduced kidney size, cortical thinning) 2
• Hematuria, pyuria, or urinary casts suggesting glomerulonephritis 4
• Pathological findings on kidney biopsy 1

Chronicity must be confirmed by demonstrating abnormalities persist for at least 3 months through repeat measurements or review of historical data. 1, 3 A single abnormal eGFR could represent acute kidney injury rather than CKD. 2

Risk Stratification

The modern KDIGO classification uses a combined approach (CGA system) incorporating:

• Cause of kidney disease 1, 3
• GFR category (G2 = 60-89 mL/min/1.73 m²) 1, 3
• Albuminuria category 1

For Stage 2 CKD specifically:

• Low risk: GFR 60-89 with UACR <30 mg/g 1
• Moderate risk: GFR 60-89 with UACR 30-300 mg/g 1
• High risk: GFR 60-89 with UACR >300 mg/g 1

Clinical Significance

Stage 2 CKD represents early kidney disease where intervention can prevent progression. 5 At this stage:

• Kidney function is only mildly reduced (60-89 mL/min/1.73 m² represents approximately 50-70% of normal young adult GFR) 1
• Most patients are asymptomatic 5, 6
• Cardiovascular risk is elevated 5-10 times compared to the general population 4
• The disease is potentially reversible or stabilizable with appropriate management 2

Common Causes

The most frequent etiologies include:

• Diabetes (20-40% of CKD cases) 4, 5
• Hypertension 4, 5
• Glomerulonephritis 4
• Nephrotoxin exposure (NSAIDs, heavy metals) 4

Management Priorities

Blood pressure control is paramount, targeting <130/80 mmHg for all CKD patients. 2 For patients with albuminuria:

• UACR 30-299 mg/g with hypertension: Initiate ACE inhibitor or ARB 2
• UACR ≥300 mg/g: ACE inhibitor or ARB strongly recommended regardless of blood pressure 2

SGLT2 inhibitors should be initiated for cardiorenal protection if UACR ≥200 mg/g, regardless of diabetes status. 2 Consider even with lower albuminuria if heart failure or high cardiovascular risk is present. 2

Statin therapy is indicated for cardiovascular risk reduction in all CKD patients. 4, 2

Monitoring Frequency

• Low risk (UACR <30 mg/g): Monitor eGFR and UACR annually 2, 3
• Moderate risk (UACR 30-300 mg/g): Monitor every 6 months 4
• High risk (UACR >300 mg/g): Monitor every 3-4 months 4

Critical Pitfalls to Avoid

Never diagnose Stage 2 CKD based on eGFR alone - this is the most common error and leads to inappropriate labeling of patients. 2, 3 Always confirm kidney damage through albuminuria testing or other markers.

Do not rely on serum creatinine alone - always calculate eGFR using validated equations (CKD-EPI 2021 is preferred). 4, 3

Do not skip albuminuria testing - eGFR and UACR provide independent prognostic information for cardiovascular events, CKD progression, and mortality. 4