What is the recommended treatment for a patient with Chronic Kidney Disease (CKD) stage 3b?

Treatment of CKD Stage 3b

For a patient with CKD stage 3b, target blood pressure should be <130/80 mmHg using an ACE inhibitor or ARB as first-line therapy, particularly if albuminuria is present, and add an SGLT2 inhibitor if the patient has type 2 diabetes with eGFR ≥20 mL/min/1.73 m².

Blood Pressure Management

Target Blood Pressure

• Aim for systolic BP <130 mmHg and diastolic BP <80 mmHg in all patients with CKD stage 3b 1.
• The 2021 KDIGO guidelines suggest an even more aggressive target of <120 mmHg systolic when tolerated, using standardized office BP measurement 1.
• However, avoid excessive BP reduction (<120 mmHg systolic) in patients with severe LV dysfunction, frailty, high fall risk, or symptomatic postural hypotension 1, 2.

First-Line Antihypertensive Therapy

ACE Inhibitors or ARBs:

• Start an ACE inhibitor as first-line therapy for CKD stage 3b, especially if albuminuria ≥300 mg/g is present 1.
• If ACE inhibitor is not tolerated (typically due to cough), switch to an ARB 1.
• For patients with moderately increased albuminuria (30-300 mg/g), ACE inhibitor or ARB is also recommended 1.
• Use the highest approved dose that is tolerated, as clinical trial benefits were achieved at these doses 1.
• Never combine ACE inhibitor + ARB + direct renin inhibitor, as this increases adverse events without additional benefit 1.

Monitoring After Initiation:

• Check BP, serum creatinine, and potassium within 2-4 weeks of starting or increasing the dose 1.
• Continue therapy unless creatinine rises >30% within 4 weeks of initiation 1.
• Manage hyperkalemia with potassium-lowering measures rather than stopping the RAS inhibitor when possible 1.
• Continue ACE inhibitor or ARB even if eGFR falls below 30 mL/min/1.73 m² unless symptomatic hypotension or uncontrolled hyperkalemia occurs 1.

Additional Antihypertensive Agents

If BP Target Not Achieved:

• Add hydrochlorothiazide 12.5 mg/day to losartan 50-100 mg for enhanced BP control and proteinuria reduction 3, 4.
• The combination of losartan/hydrochlorothiazide reduces proteinuria more effectively than losartan alone, even with similar BP control 3, 4.
• Consider other agents (calcium channel blockers, beta-blockers) as needed to reach target BP 1.

Diabetes-Specific Management

SGLT2 Inhibitors:

• For patients with type 2 diabetes and CKD stage 3b (eGFR ≥20 mL/min/1.73 m²), add an SGLT2 inhibitor to reduce CKD progression and cardiovascular events 1, 2.
• This recommendation applies regardless of albuminuria level 1.
• Continue SGLT2 inhibitor even if eGFR falls below 20 mL/min/1.73 m² unless not tolerated or kidney replacement therapy is initiated 1.
• Withhold SGLT2 inhibitor during prolonged fasting, surgery, or critical illness due to ketosis risk 1.

Nonsteroidal Mineralocorticoid Receptor Antagonists:

• Consider adding a nonsteroidal MRA (if eGFR ≥25 mL/min/1.73 m²) for additional cardiovascular risk reduction in patients with albuminuria 1.

Cardiovascular Risk Reduction

Statin Therapy:

• Initiate statin or statin/ezetimibe combination for all patients ≥50 years with CKD stage 3b (Grade 1A recommendation) 2, 5.
• For patients aged 18-49 years, prescribe statin if they have known coronary disease, diabetes, prior stroke, or 10-year CV risk >10% 2, 5.

Aspirin:

• Use low-dose aspirin for secondary prevention in patients with established cardiovascular disease 2, 5.

Dietary and Lifestyle Modifications

Dietary Protein:

• Limit dietary protein intake to 0.8 g/kg body weight per day for non-dialysis-dependent CKD stage 3b 1.

Sodium Restriction:

• Restrict sodium intake to <5 g sodium chloride per day (<2 g sodium) 1, 2, 5.
• Avoid salt substitutes rich in potassium due to hyperkalemia risk 1.

Other Dietary Recommendations:

• Adopt a plant-based Mediterranean-style diet 2, 5.
• Limit alcohol, meats, and high-fructose corn syrup 5.

Physical Activity:

• Recommend moderate-intensity physical activity for ≥150 minutes per week or to the level compatible with cardiovascular tolerance 1.

Medication Safety

Avoid Nephrotoxins:

• Avoid NSAIDs, which can accelerate CKD progression 5, 6.
• Review all medications for appropriate dose adjustments in CKD stage 3b 5, 6.

Metformin Caution:

• Use metformin cautiously or avoid if serum creatinine ≥1.5 mg/dL in men or ≥1.4 mg/dL in women 5.

Monitoring for CKD Complications

Regular Monitoring:

• Monitor for hyperkalemia, metabolic acidosis, hyperphosphatemia, vitamin D deficiency, secondary hyperparathyroidism, and anemia 6.
• Screen for albuminuria using spot urine albumin-to-creatinine ratio 1.

Nephrology Referral Criteria

Refer to Nephrology if:

• eGFR <30 mL/min/1.73 m² (approaching stage 4 CKD) 1, 5.
• Continuously increasing albuminuria or continuously decreasing eGFR 1.
• Albuminuria ≥300 mg per 24 hours (high risk of progression) 5, 6.
• Rapid decline in eGFR 5.
• Uncertainty about etiology of kidney disease or difficult management issues 1.

Common Pitfalls to Avoid

• Do not withhold ACE inhibitor/ARB due to mild creatinine elevation (<30% increase), as this is expected and acceptable 1.
• Do not combine ACE inhibitor with ARB, as this increases harm without benefit 1.
• Do not discontinue SGLT2 inhibitor in diabetic patients when eGFR drops below 20, as continuation is reasonable 1.
• Remember that most CKD stage 3 patients die from cardiovascular causes rather than progressing to ESRD, making cardiovascular risk reduction paramount 5.