What is the diagnosis and treatment of hypertension?

Hypertension Diagnosis

Hypertension is diagnosed when office blood pressure measurements are ≥140/90 mm Hg on repeated visits, or ≥130/80 mm Hg in high-risk patients (those with existing cardiovascular disease, diabetes, chronic kidney disease, or high cardiovascular risk). 1, 2

Diagnostic Criteria and Blood Pressure Categories

The current classification system defines four blood pressure categories 2:

• Normal: <120/<80 mm Hg
• Elevated: 120-129 systolic AND <80 mm Hg diastolic
• Stage 1 Hypertension: 130-139 systolic OR 80-89 mm Hg diastolic
• Stage 2 Hypertension: ≥140 systolic OR ≥90 mm Hg diastolic

The diagnosis should not be made on a single office visit. Typically 2-3 office visits at 1-4 week intervals are required to confirm hypertension, though diagnosis may be made on a single visit if BP is ≥180/110 mm Hg with evidence of cardiovascular disease. 1

Proper Blood Pressure Measurement Technique

Accurate measurement is critical to avoid misdiagnosis. The patient must be 1, 2:

• Seated in a quiet room with comfortable temperature
• Resting for 3-5 minutes before measurement
• Feet flat on floor, legs uncrossed
• Back supported on chair
• Arm resting on table with mid-arm at heart level
• Bladder emptied beforehand
• No smoking, caffeine, or exercise for 30 minutes prior

Use a validated electronic (oscillometric) upper-arm cuff device with appropriate cuff size for the patient's arm circumference—smaller cuffs overestimate and larger cuffs underestimate blood pressure. 1

Take 3 measurements with 1 minute between them and calculate the average of the last 2 measurements. If the first reading is <130/85 mm Hg, no further measurement is required at that visit. 1

Measure BP in both arms at the initial visit, preferably simultaneously. If there is a consistent difference >10 mm Hg in repeated measurements, use the arm with the higher BP. If the difference is >20 mm Hg, consider further investigation for vascular abnormalities. 1

Confirmation with Out-of-Office Monitoring

The diagnosis should be confirmed by out-of-office BP measurement whenever possible and available. 1, 2 This helps exclude white coat hypertension and provides more accurate assessment:

• Home BP monitoring: Hypertension confirmed if readings are ≥135/85 mm Hg 1
• 24-hour ambulatory BP monitoring: Hypertension confirmed if average is ≥130/80 mm Hg 1

Initial Diagnostic Workup

Once hypertension is confirmed, obtain the following tests to screen for comorbidities, target organ damage, and secondary causes—but only when testing does not delay starting treatment 1, 2:

• 12-lead ECG to assess for left ventricular hypertrophy or ischemia
• Basic metabolic panel (serum sodium, potassium, creatinine, eGFR) to evaluate kidney function and electrolytes
• Fasting lipid panel for cardiovascular risk assessment
• Fasting glucose or HbA1c to screen for diabetes
• Urinalysis with albumin-to-creatinine ratio to detect proteinuria
• Thyroid-stimulating hormone (TSH) to exclude thyroid disorders

Screening for Secondary Hypertension

Consider screening for secondary causes in specific clinical scenarios 1:

• Early onset hypertension (<30 years of age), particularly without risk factors (obesity, metabolic syndrome, family history)
• Resistant hypertension (BP ≥140/90 mm Hg despite 3+ medications at optimal doses including a diuretic)
• Sudden deterioration in BP control
• Hypertensive urgency or emergency
• Strong clinical clues suggesting secondary causes (hypokalemia, abdominal bruit, features of Cushing syndrome)

The most common secondary causes are renal parenchymal disease, renovascular hypertension, primary aldosteronism, chronic sleep apnea, and drug/substance-induced hypertension. 1

Before extensive workup for secondary causes in resistant hypertension, first exclude pseudoresistance by confirming accurate BP measurement technique, assessing medication adherence, obtaining home or ambulatory BP readings, and reviewing for interfering substances (NSAIDs, decongestants, stimulants, excessive alcohol). 1, 2

Common Pitfalls to Avoid

• Improper cuff size: Using standard adult cuff on obese arms significantly overestimates BP 1
• White coat hypertension: Office readings may be 20-30 mm Hg higher than home readings; confirm with out-of-office monitoring 1
• Single visit diagnosis: Except in hypertensive emergencies with target organ damage, always confirm on multiple visits 1
• Talking during measurement: Both patient and staff must remain silent during and between measurements 1
• Unsupported back or dangling feet: Can falsely elevate readings by 5-10 mm Hg 1