Hypertension in Chronic Kidney Disease(CKD)

Hypertension is both a major cause and a common complication of Chronic Kidney Disease (CKD). Persistent elevation of blood pressure accelerates the decline in kidney function, increases proteinuria, and substantially raises the risk of cardiovascular morbidity and mortality. Conversely, worsening kidney disease contributes to poor blood pressure control through sodium retention, fluid overload, activation of the renin-angiotensin-aldosterone system (RAAS), and increased sympathetic nervous system activity.

Early diagnosis, aggressive blood pressure control, reduction of proteinuria, and management of cardiovascular risk factors are essential to slow CKD progression and reduce adverse cardiovascular outcomes.

Epidemiology

Hypertension affects more than 80% of patients with Chronic Kidney Disease, with prevalence increasing as kidney function declines. It is one of the leading causes of CKD worldwide and contributes significantly to end-stage kidney disease (ESKD). Patients with both hypertension and CKD have a markedly increased risk of stroke, heart failure, myocardial infarction, and premature death. In Tanzania and other low- and middle-income countries, delayed diagnosis and inadequate blood pressure control remain major challenges.

Risk factors

Common risk factors include:

• Chronic Kidney Disease

• Diabetes mellitus

• Persistent proteinuria

• Increasing age

• Obesity

• High dietary sodium intake

• Family history of hypertension

• Cardiovascular disease

• Dyslipidaemia

• Smoking

• Physical inactivity

• Excess alcohol intake

• Fluid overload

• Secondary causes of hypertension

Pathophysiology

Hypertension in CKD develops through several mechanisms, including sodium and water retention, activation of the renin-angiotensin-aldosterone system (RAAS), increased sympathetic nervous system activity, endothelial dysfunction, and arterial stiffness.

Persistent hypertension causes increased intraglomerular pressure, resulting in progressive glomerular injury, worsening proteinuria, nephron loss, and declining glomerular filtration rate. Proteinuria itself contributes to tubulointerstitial inflammation and fibrosis, creating a cycle of progressive kidney damage. Effective blood pressure control, particularly with RAAS blockade in patients with proteinuria, significantly slows disease progression.

Clinical presentation

Many patients are asymptomatic, particularly during the early stages.

Patients may present with:

• Persistent elevated blood pressure

• Headache

• Dizziness

• Blurred vision

• Fatigue

• Reduced exercise tolerance

• Lower limb oedema

• Shortness of breath due to fluid overload

• Nocturia

• Symptoms of chronic kidney disease

Clinical signs may include:

• Elevated blood pressure

• Peripheral oedema

• Features of fluid overload

• Hypertensive retinopathy

• Left ventricular hypertrophy

• Signs of chronic kidney disease

Diagnostic criteria

Hypertension in patients with CKD is diagnosed according to standard blood pressure criteria together with evidence of chronic kidney disease.

Blood pressure targets are:

• CKD without significant proteinuria: target blood pressure <140/90 mmHg.

• CKD with proteinuria: target blood pressure <130/80 mmHg.

Evaluation should also include assessment of albuminuria or proteinuria, kidney function, cardiovascular risk factors, and exclusion of secondary causes of hypertension where indicated.

Investigations

Recommended investigations include:

Blood pressure assessment

• Ambulatory blood pressure monitoring where available.

• Repeated office blood pressure measurements.

Kidney assessment

• Serum creatinine.

• Blood urea nitrogen (BUN).

• Estimated glomerular filtration rate (eGFR).

• Serum electrolytes.

• Urinalysis.

• Urine albumin-creatinine ratio (ACR) or urine protein-creatinine ratio (PCR).

Additional investigations

• Kidney-Ureter-Bladder (KUB) ultrasound.

• Full blood count.

• Electrocardiogram (ECG).

• Lipid profile.

• Blood glucose or HbA1c where appropriate.

• Investigations for secondary causes of hypertension when clinically suspected.

Management

Management aims to:

• Achieve target blood pressure.

• Reduce proteinuria.

• Slow progression of chronic kidney disease.

• Prevent cardiovascular complications.

• Manage fluid overload.

Non-pharmacological treatment

General measures include:

• Restrict dietary sodium intake.

• Encourage weight reduction in overweight patients.

• Encourage regular physical activity.

• Stop smoking.

• Limit alcohol intake.

• Control diabetes mellitus.

• Reduce cardiovascular risk factors.

• Avoid nephrotoxic medications.

• Monitor kidney function and serum potassium regularly.

Pharmacological treatment

Treatment should be individualized according to the stage of CKD, degree of proteinuria, kidney function, and associated comorbidities. Whenever possible, at least one antihypertensive medication should be administered at bedtime.

CKD Stages 1–2 (eGFR ≥60 mL/min/1.73 m²)

Patients with proteinuria (>500 mg/day)

First-line treatment:

• Enalapril 10–20 mg orally every 12 hours.

• OR

• Lisinopril 5–10 mg orally once daily, titrated to a maximum of 40 mg once daily.

• OR

• Irbesartan 150–300 mg orally once daily.

If blood pressure remains uncontrolled and oedema is present:

• Add a diuretic according to the management of fluid overload.

If additional blood pressure control is required:

• Diltiazem 60–120 mg orally every 12 hours.

• OR

• Verapamil 40–80 mg orally every 8 hours.

Patients receiving ACE inhibitors or angiotensin receptor blockers should have serum potassium monitored and serum creatinine repeated 5–7 days after initiation or dose adjustment.

Patients without significant proteinuria (<500 mg/day)

If oedema is present:

• Treat fluid overload with appropriate diuretic therapy.

If blood pressure remains uncontrolled:

• Add an ACE inhibitor or angiotensin receptor blocker as above.

If additional treatment is required:

• Diltiazem 60–120 mg orally every 12 hours.

• OR

• Verapamil 40–80 mg orally every 8 hours.

If blood pressure remains uncontrolled despite combination therapy, additional agents may include:

• Spironolactone.

• OR

• Eplerenone.

• Hydralazine 12.5–50 mg orally.

• Amlodipine 5–10 mg orally once daily.

• OR

• Nifedipine 20–40 mg orally every 12 hours.

• Atenolol 25–100 mg orally once daily.

If beta-blockers above are contraindicated or unavailable:

• Carvedilol 6.25–25 mg orally every 12 hours.

• OR

• Bisoprolol 2.5–5 mg orally once daily.

Additional therapy where required:

• Doxazosin 1 mg orally once daily, titrated to a maximum of 16 mg daily.

• OR

• Methyldopa 250–1000 mg orally every 8 hours.

CKD Stage 3 (eGFR 30–59 mL/min/1.73 m²)

Management is similar to Stages 1–2 with careful dose adjustment.

• Lisinopril 5–10 mg orally once daily where indicated.

Monitor serum potassium and kidney function more frequently.

CKD Stage 4 (eGFR 15–29 mL/min/1.73 m²)

ACE inhibitors and angiotensin receptor blockers should generally be avoided unless under specialist supervision.

Treatment should focus on:

• Careful fluid control.

• Appropriate antihypertensive therapy with alternative agents.

• Frequent monitoring of kidney function and electrolytes.

CKD Stage 5 (eGFR <15 mL/min/1.73 m²) or patients receiving dialysis

Dose adjustment is required because of markedly reduced kidney clearance.

Suitable medications include:

• Bisoprolol 2.5 mg orally once daily.

• Methyldopa 250 mg–1 g orally once daily.

• Doxazosin 1 mg orally once daily, titrated to a maximum of 16 mg daily.

Management should also include:

• Strict dietary salt restriction.

• Appropriate ultrafiltration during dialysis.

• Careful assessment of fluid status.

Management of fluid overload

Patients with fluid overload should receive prompt treatment and assessment for other possible causes of oedema.

Recommended treatment includes:

• Furosemide 40–80 mg orally or by slow intravenous injection every 12 hours.

• OR

• Torsemide 10–20 mg orally once daily, titrated up to a maximum of 200 mg daily.

If response is inadequate:

• Repeat the loop diuretic after one hour if clinically indicated.

For resistant oedema without hypokalaemia:

• Furosemide by slow continuous intravenous infusion (maximum 600 mg/day) together with:

  • Hydrochlorothiazide 25–50 mg orally every 12 hours.

  • OR

  • Metolazone 2.5–20 mg orally once daily.

Intravenous maintenance fluids should be avoided in patients with fluid overload unless clinically indicated. If intravenous access is required, a heparin lock or similar device should be used.

Referral

Refer patients urgently to a nephrologist or physician when:

• CKD Stage 3–5.

• All children with CKD.

• Persistent haematuria.

• Persistent proteinuria.

• Elevated serum creatinine or blood urea requiring further evaluation.

• Uncontrolled hypertension despite appropriate therapy.

• Persistent or severe fluid overload.

• CKD associated with hyperlipidaemia requiring specialist management.

• Persistent proteinuria despite ACE inhibitor therapy.

• Rapid decline in kidney function.

• Suspected need for kidney replacement therapy.

Patients who may require dialysis or kidney transplantation should be referred early, preferably when eGFR falls below 30 mL/min/1.73 m² or immediately once advanced CKD is suspected.

Complications

Potential complications include:

• Progressive chronic kidney disease.

• End-stage kidney disease.

• Resistant hypertension.

• Persistent proteinuria.

• Acute pulmonary oedema.

• Congestive heart failure.

• Hyperkalaemia.

• Cardiovascular disease.

• Stroke.

• Myocardial infarction.

• Dialysis dependence.

• Premature death.

Prognosis

The prognosis depends on the severity of hypertension, degree of proteinuria, underlying kidney disease, cardiovascular risk factors, and adherence to treatment. Early diagnosis, achievement of blood pressure targets, effective reduction of proteinuria, and comprehensive cardiovascular risk management significantly delay CKD progression and reduce cardiovascular morbidity and mortality. Poorly controlled hypertension is associated with accelerated kidney failure and increased risk of cardiovascular events.

Prevention

Preventive measures include:

• Routine screening for hypertension in individuals at risk of CKD.

• Early diagnosis and treatment of chronic kidney disease.

• Strict blood pressure control according to recommended targets.

• Early treatment of proteinuria using ACE inhibitors or angiotensin receptor blockers where appropriate.

• Dietary sodium restriction.

• Good glycaemic control in patients with diabetes mellitus.

• Smoking cessation.

• Maintenance of healthy body weight.

• Regular physical activity.

• Avoidance of nephrotoxic medications.

• Regular monitoring of kidney function, serum potassium, and albuminuria.

• Early referral of patients with progressive CKD to nephrology services.