What are the current guidelines for diagnosing and managing hypertension?

Current Evidence on Hypertension Diagnosis and Management

Diagnosis of Hypertension

Hypertension should be diagnosed using multiple blood pressure measurements taken across 2-3 separate office visits at 1-4 week intervals, with mandatory confirmation using out-of-office monitoring (home or ambulatory BP monitoring) for borderline cases to exclude white coat hypertension. 1, 2

Proper Blood Pressure Measurement Technique

The accuracy of diagnosis depends critically on proper measurement technique:

• Patient preparation: Avoid smoking, caffeine, and exercise for 30 minutes before measurement; empty bladder; sit relaxed in a quiet room with comfortable temperature for 3-5 minutes without talking 1, 2

• Patient positioning: Seated with arm resting on table at heart level, back supported on chair, legs uncrossed with feet flat on floor 1, 2

• Device selection: Use a validated electronic (oscillometric) upper-arm cuff device or calibrated auscultatory device with appropriate cuff size covering 75-100% of arm circumference 1, 2

• Measurement protocol: Take three measurements with 1-minute intervals between each, and calculate the average of the last two measurements 1, 2

Diagnostic Thresholds

The 2017 ACC/AHA guidelines redefined hypertension thresholds, which differ from older international guidelines:

• Stage 1 hypertension: Office BP 130-139/80-89 mmHg (ACC/AHA 2017) 3 versus ≥140/90 mmHg (most international guidelines) 3

• Stage 2 hypertension: Office BP ≥140/90 mmHg (ACC/AHA 2017) 3 versus ≥160/100 mmHg (older guidelines) 3

• Out-of-office thresholds: Home BP monitoring >135/85 mmHg; 24-hour ambulatory BP monitoring >125/80 mmHg 2

Out-of-Office Blood Pressure Confirmation

Out-of-office measurements are more reproducible than office measurements and more closely associated with hypertension-induced organ damage and cardiovascular risk. 2

• NICE and Canadian guidelines uniquely recommend that ambulatory or home BP monitoring should be used to confirm all new diagnoses of hypertension 3

• ACC/AHA guidelines recommend out-of-office monitoring to detect white coat hypertension (high office BP but normal out-of-office BP) and masked hypertension (normal office BP but high out-of-office BP), which carry different cardiovascular risks 3

• Canadian guidelines are most stringent: if office BP is 140-160/90-100 mmHg, require measurements on 4-5 separate occasions or use self-monitoring/ambulatory monitoring before diagnosis 3

Essential Diagnostic Workup

After confirming hypertension, the following investigations are mandatory:

• Laboratory tests: Serum sodium, potassium, creatinine, estimated glomerular filtration rate (eGFR), fasting blood glucose, lipid profile 1, 2

• Urinalysis: Dipstick test for protein and blood 1, 2

• 12-lead ECG: To detect atrial fibrillation, left ventricular hypertrophy, and ischemic heart disease 1, 2

• Physical examination: Focus on pulse characteristics, jugular venous pressure, apex beat, extra heart sounds, basal crackles, peripheral edema, vascular bruits, and radio-femoral delay to identify secondary causes and target organ damage 3, 2

Management of Hypertension

Lifestyle Modifications

Lifestyle modifications are the foundation of hypertension management and should be initiated for all patients with elevated BP, regardless of whether pharmacological therapy is started. 1, 4

The most effective interventions include:

• Dietary sodium restriction: Reduce to as low as 1500 mg/day 1

• DASH diet: Emphasize a meal plan low in sodium and high in dietary potassium 1, 4

• Physical activity: Moderate-intensity aerobic exercise and resistance training 1

• Weight management: Aim for healthy BMI and waist circumference 1

• Alcohol limitation: Restrict consumption 1

• Smoking cessation: Complete cessation recommended 1

The BP-lowering effects of individual lifestyle components are partially additive and enhance the efficacy of pharmacologic therapy 4.

Pharmacological Treatment

First-line pharmacotherapy should include one or more of the following drug classes: thiazide or thiazide-like diuretics (chlorthalidone, hydrochlorothiazide), ACE inhibitors or angiotensin receptor blockers (lisinopril, enalapril, candesartan), and calcium channel blockers (amlodipine). 5, 6, 4

Treatment Targets

• Adults <65 years: Target BP <130/80 mmHg 4

• Adults ≥65 years: Target systolic BP <130 mmHg 4

• Patients with diabetes or chronic kidney disease: Some guidelines (CHEP, Taiwan, ESH/ESC) recommend lower targets, though this remains an area of variation 3

Drug Selection Considerations

There is consensus across guidelines on several key principles:

• Beta-blockers are not recommended as first-line therapy for the general population (JNC 8, ASH/ISH, AHA/ACC/CDC, NICE, Taiwan guidelines); they are restricted to patients <60 years in Canadian guidelines or reserved for specific indications (history of myocardial infarction, heart failure, angina) 3

• Black patients should be initiated on calcium channel blockers or thiazide diuretics as first-line therapy 3

• ACE inhibitors and ARBs should not be used in combination due to lack of benefit and increased adverse effects 3

• Multiple drugs are required in most cases to achieve BP control 3

• Single-pill combination therapy is recommended by China and Taiwan guidelines for initial treatment when more than one drug is required, and simplifies regimens using long-acting drugs 3

• Preferred 3-drug combination: Calcium channel blocker + thiazide diuretic + ACE inhibitor/ARB 3

Evidence for BP Lowering

An SBP reduction of 10 mmHg decreases risk of cardiovascular disease events by approximately 20-30%, with the largest benefit being reduction in stroke risk. 4

Randomized clinical trials have established that it is blood pressure reduction itself, rather than specific pharmacologic properties of drugs, that is largely responsible for cardiovascular benefits 5, 6, 4.

Common Diagnostic and Management Pitfalls

Critical errors to avoid:

• Never diagnose hypertension based on a single office visit (except BP ≥180/110 mmHg with evidence of cardiovascular disease) 2

• Using incorrect cuff size leads to inaccurate measurements 2

• Failing to allow adequate rest period before measurement (minimum 3-5 minutes) 1, 2

• Talking during BP measurement artificially elevates readings 1, 2

• Not screening for white coat or masked hypertension in borderline cases results in inappropriate treatment decisions 2

• Inadequate follow-up: Only 44% of US adults with hypertension have their BP controlled to <140/90 mmHg, highlighting the need for regular monitoring and treatment adjustment 4

Screening Recommendations

Adults aged <40 years should undergo opportunistic screening at least every 3 years; adults aged ≥40 years should be screened annually. 1

For individuals with elevated BP not meeting treatment thresholds, repeat BP measurement and cardiovascular risk assessment within 1 year is recommended 1.