What is the best approach to manage blood pressure in an African American patient with impaired renal function (GFR < 69)?

Blood Pressure Management in African Americans with CKD (GFR < 69)

Target a systolic blood pressure of <130/80 mmHg in African American patients with impaired renal function (GFR < 69 mL/min/1.73 m²), using an ACE inhibitor or ARB as the foundation of therapy, combined with a thiazide-type diuretic or calcium channel blocker to achieve goal. 1

Blood Pressure Target

• The target blood pressure should be <130/80 mmHg for African American patients with CKD stage 3 (GFR 30-59 mL/min/1.73 m²). 1
• For patients with significant proteinuria (>0.22 g/g or >1 g/day), more intensive blood pressure control (MAP ≤92 mmHg, approximately equivalent to <125/75 mmHg) provides additional renoprotection and slows progression to ESRD. 1, 2
• The SPRINT trial demonstrated that intensive BP control (SBP <120 mmHg) reduced cardiovascular events and mortality in high-risk patients with CKD without increasing kidney disease progression, though this very intensive target may not be necessary for all patients. 1

First-Line Medication Selection

ACE inhibitors or ARBs should be the cornerstone of antihypertensive therapy in African Americans with CKD, despite the common misconception that they are ineffective in this population. 3, 4, 5

Specific Evidence for African Americans with CKD:

• The AASK trial specifically studied African Americans with hypertensive kidney disease (GFR 20-65 mL/min/1.73 m²) and found that ramipril (an ACE inhibitor) reduced the risk of doubling serum creatinine or ESRD by 38% compared to amlodipine and by 22% compared to metoprolol. 1, 5
• In African Americans with proteinuria (UPCR >0.22 g/g), ACE inhibitors showed a 24% risk reduction for progression to ESRD over 9.1 years of follow-up. 1
• While ACE inhibitors may produce smaller blood pressure reductions as monotherapy in African Americans compared to non-Black patients, they provide superior renoprotection independent of their blood pressure-lowering effects. 6, 4

Practical Medication Approach:

• Start with ramipril 2.5-10 mg daily or lisinopril 10-40 mg daily as initial therapy. 5
• Alternative: Use an ARB such as losartan 50-100 mg daily if ACE inhibitor is not tolerated (noting that African Americans have a greater risk of angioedema with ACE inhibitors). 3, 7, 8
• Monitor for a 10-25% increase in serum creatinine within 2-4 weeks of initiation, which is expected and hemodynamic in nature; do not discontinue unless the increase exceeds 30%. 1

Combination Therapy Strategy

Most African American patients with CKD will require 2-3 antihypertensive medications to achieve BP targets <130/80 mmHg. 1, 7, 9

Step-by-Step Algorithm:

1. Initial therapy: ACE inhibitor or ARB at moderate dose 3, 4, 5

2. Add second agent if BP remains >130/80 mmHg:

   • Preferred: Thiazide-type diuretic (chlorthalidone 12.5-25 mg daily) - more effective than hydrochlorothiazide for cardiovascular outcomes and has longer half-life 7, 9
   • Alternative: Dihydropyridine calcium channel blocker (amlodipine 5-10 mg daily) - particularly effective in African Americans 3, 7, 9

3. Triple therapy if BP remains uncontrolled:

   • ACE inhibitor/ARB + calcium channel blocker + thiazide diuretic 9
   • This combination addresses the typically low-renin physiology in African Americans while providing renoprotection 6, 4

4. Resistant hypertension (BP >130/80 on 3 drugs):

   • Add spironolactone 25-50 mg daily (monitor potassium closely given CKD and RAS blockade) 7
   • Alternative: Add doxazosin, amiloride, or beta-blocker if spironolactone not tolerated 9

Critical Monitoring Parameters

• Measure serum creatinine and potassium 2-4 weeks after initiating or increasing dose of ACE inhibitor/ARB. 1
• Check blood pressure at 3-month intervals once stable to ensure sustained control. 3
• Assess urine protein-to-creatinine ratio every 6-12 months - higher proteinuria indicates need for more intensive BP control (target MAP ≤92 mmHg). 1, 2
• Monitor for hyperkalemia - particularly important with combination of ACE inhibitor/ARB and CKD; consider discontinuing if potassium >5.5 mEq/L despite dietary modification. 6

Race-Specific Considerations

• African Americans demonstrate a stronger relationship between achieved blood pressure and GFR decline compared to White patients (sevenfold stronger in MDRD study), making BP control even more critical in this population. 2
• The lower blood pressure goal (MAP ≤92 mmHg) slowed GFR decline by 11.8 mL/min over 3 years in African Americans versus only 0.3 mL/min in White patients in the MDRD study. 2
• Do not avoid ACE inhibitors or ARBs based on race alone - the AASK trial definitively showed superior renoprotection with ACE inhibitors in African Americans with hypertensive nephrosclerosis despite smaller monotherapy BP reductions. 4, 5

Common Pitfalls to Avoid

• Pitfall: Avoiding RAS blockade in African Americans due to perceived ineffectiveness

  • Solution: Use ACE inhibitor/ARB as foundation, but combine with diuretic or CCB to achieve BP goals 4, 5

• Pitfall: Accepting BP of 140/90 mmHg as adequate in CKD patients

  • Solution: Target <130/80 mmHg for all CKD patients; consider <125/75 mmHg if proteinuria >1 g/day 1

• Pitfall: Discontinuing ACE inhibitor/ARB with modest creatinine elevation (10-25%)

  • Solution: Accept up to 30% creatinine increase as hemodynamic effect; only discontinue if >30% increase or hyperkalemia develops 1

• Pitfall: Using beta-blockers or non-dihydropyridine CCBs as first-line agents

  • Solution: Reserve these for specific indications (heart failure, coronary disease); they showed inferior renoprotection in AASK trial 5