What is the recommended management for a patient with Chronic Kidney Disease (CKD) Stage IIIb?

Management of CKD Stage IIIb

For patients with CKD Stage IIIb (eGFR 30-44 mL/min/1.73 m²), target blood pressure <120 mmHg systolic using standardized office measurement when tolerated, initiate ACE inhibitor or ARB if albuminuria is present, and implement comprehensive lifestyle modifications including sodium restriction and regular physical activity. 1

Blood Pressure Management

Target Blood Pressure

• Aim for systolic BP <120 mmHg using standardized office measurement for cardiovascular and kidney protection 1
• If albuminuria ≥30 mg/24 hours is present, some guidelines suggest targeting <130/80 mmHg, though the 2021 KDIGO guideline recommends the more intensive <120 mmHg target 1
• For patients without albuminuria, maintain BP <140/90 mmHg 1
• Critical caveat: The <120 mmHg target applies only to standardized office BP measurements; applying this target to non-standardized measurements is potentially hazardous 1

Antihypertensive Medication Selection

First-line therapy based on albuminuria status:

• If albuminuria ≥300 mg/24 hours (A3): Start ACE inhibitor or ARB immediately—this is a strong recommendation 1
• If albuminuria 30-300 mg/24 hours (A2): Start ACE inhibitor or ARB—this is a weaker recommendation but still advised 1
• If no albuminuria (<30 mg/24 hours): ACE inhibitor or ARB may be reasonable but is not mandatory; can use thiazide-type diuretic, calcium channel blocker, ACE inhibitor, or ARB as initial therapy 1

Medication titration and monitoring:

• Titrate ACE inhibitor or ARB to the highest approved dose that is tolerated to achieve maximum benefit 1
• Check serum creatinine and potassium within 2-4 weeks after starting or increasing the dose 1
• Continue therapy unless creatinine rises >30% within 4 weeks of initiation or dose increase 1
• Manage hyperkalemia with potassium-lowering measures rather than immediately stopping the ACE inhibitor or ARB 1

Additional agents to reach BP target:

• Most patients require 2-3 antihypertensive medications to achieve BP <120 mmHg 2
• After ACE inhibitor or ARB, add a long-acting dihydropyridine calcium channel blocker 2
• Third-line: Add thiazide-type diuretic (or loop diuretic if eGFR <30 mL/min/1.73 m², which applies to Stage IIIb patients approaching Stage IV) 2
• Never combine ACE inhibitor + ARB together—this increases risk of hyperkalemia, hypotension, and acute kidney injury 1, 2

Lifestyle Modifications

Dietary Sodium Restriction

• Restrict sodium intake to <2 g/day (equivalent to <5 g sodium chloride per day) 1
• Exception: Do not restrict sodium in patients with salt-wasting nephropathy 1
• Caution with DASH diet or potassium-rich salt substitutes in Stage IIIb CKD due to risk of hyperkalemia from impaired potassium excretion 1

Physical Activity

• Recommend moderate-intensity physical activity for at least 150 minutes per week, adjusted to cardiovascular and physical tolerance 1
• Consider cardiorespiratory fitness, physical limitations, cognitive function, and fall risk when prescribing exercise intensity 1
• Even activity below general population targets provides important health benefits 1

Protein Intake

• Reduce protein intake to 0.8 g/kg/day with appropriate nutritional education 1

Monitoring Strategy

Frequency of Monitoring

• Stage IIIb CKD requires monitoring 2-4 times per year depending on albuminuria category 1
• Higher albuminuria levels necessitate more frequent monitoring 1

Parameters to Monitor

• eGFR and serum creatinine to assess kidney function trajectory 1
• Urine albumin-to-creatinine ratio to track proteinuria 1
• Serum potassium, especially when using ACE inhibitors, ARBs, or mineralocorticoid receptor antagonists 1
• Blood pressure at every visit, checking for postural hypotension 1
• Complications of CKD: hyperkalemia, metabolic acidosis, hyperphosphatemia, vitamin D deficiency, secondary hyperparathyroidism, and anemia 3

Nephrology Referral Criteria

Refer to nephrology if:

• eGFR <30 mL/min/1.73 m² (approaching or entering Stage IV) 3
• Albuminuria ≥300 mg/24 hours 3
• Rapid decline in eGFR (>25% decline with change in GFR category) 1

Additional Considerations

Cardiovascular Risk Reduction

• Consider statin therapy for cardiovascular risk reduction 3
• Assess for heart failure, particularly if symptoms develop; BNP levels are elevated in CKD independent of cardiac disease 2

Medication Safety

• Avoid nephrotoxins, particularly NSAIDs 3
• Adjust dosing of renally cleared medications including many antibiotics and oral hypoglycemic agents 3

Special Populations

• In elderly or frail patients, less intensive BP targets may be reasonable to avoid symptomatic postural hypotension 1
• Discontinue ACE inhibitors or ARBs in women considering pregnancy or who become pregnant 1