What are the recommended steps to diagnose hypertension in adults over 18 with risk factors?

How to Diagnose Hypertension in Adults Over 18 with Risk Factors

Screen all adults ≥18 years with office blood pressure measurement using an average of ≥2 readings, then confirm the diagnosis with out-of-office measurements (home or ambulatory monitoring) before starting treatment. 1, 2

Initial Screening Protocol

Office Blood Pressure Measurement Technique

• Take at least 2 measurements while the patient is seated, allowing ≥5 minutes between office entry and measurement 1
• Use an appropriately sized arm cuff positioned at the level of the right atrium 1
• Calculate the average of the second and third measurements if taking three readings 1
• Multiple measurements over time have superior positive predictive value compared to single measurements 1

Screening Frequency Based on Risk

• Adults 18-39 years with BP <120/80 mm Hg and no risk factors: Screen every 3-5 years 1
• Adults ≥40 years or those <40 who are overweight/obese or Black: Screen annually 1
• Adults with BP 120-139/75-79 mm Hg: Screen annually 1, 3

Diagnostic Confirmation Requirements

Before initiating treatment, obtain blood pressure measurements outside the clinical setting to confirm the diagnosis and exclude white-coat hypertension. 1

Confirmation Strategy by Blood Pressure Level

• BP <160/100 mm Hg at initial visit: Confirm at a follow-up visit within 1 month using an average of ≥2 measurements 1
• Untreated BP 130-159/80-99 mm Hg: Use daytime ambulatory BP monitoring (ABPM) or home BP monitoring (HBPM) to screen for white-coat hypertension 1
• BP consistently 120-129/75-79 mm Hg: Consider HBPM or ABPM to screen for masked hypertension 1

Why Out-of-Office Confirmation Matters

White-coat hypertension affects 15-30% of patients believed to have hypertension based on office readings alone 1. Out-of-office measurements prevent unnecessary treatment and its associated harms while identifying true hypertension that requires intervention 1, 2.

Initial Evaluation After Diagnosis Confirmation

Essential Laboratory Testing

Once hypertension is confirmed, order the following baseline tests 4:

• Comprehensive metabolic panel (sodium, potassium, calcium, creatinine with eGFR) to detect electrolyte abnormalities suggesting secondary causes and assess kidney function 4
• Fasting blood glucose to identify diabetes, which lowers treatment thresholds 4
• Lipid profile (total cholesterol, LDL, HDL, triglycerides) for cardiovascular risk stratification 4
• Thyroid-stimulating hormone to detect hypothyroidism and hyperthyroidism as remediable causes 4
• Urinary albumin-to-creatinine ratio (not urine dipstick alone) for early kidney damage detection 4
• 12-lead electrocardiogram to detect left ventricular hypertrophy, arrhythmias, and ischemic heart disease 4
• Complete blood count to detect anemia or hematologic abnormalities 4

Special Consideration for Young Adults

In adults ≤30 years with elevated brachial BP, measure thigh blood pressure; if lower than arm pressures, consider coarctation of the aorta. 4, 5

Screening for Secondary Hypertension

High-Risk Features Requiring Investigation

Suspect secondary hypertension when any of the following are present 5:

• Age of onset <30 years (especially without obesity or family history) 5
• Resistant hypertension (BP >140/90 mm Hg despite optimal doses of ≥3 drugs including a diuretic) 5
• Severe or accelerated/malignant hypertension with grade III-IV retinopathy 5
• Abrupt onset or sudden worsening of previously controlled hypertension 5
• Unprovoked hypokalemia suggesting primary aldosteronism 5
• Target organ damage disproportionate to duration or severity of hypertension 5

Age-Based Screening Threshold

The European Society of Cardiology recommends comprehensive screening for secondary hypertension in adults diagnosed before age 40 years (except obese young adults where sleep apnea should be evaluated first) 5. However, primary hypertension can occur in younger patients, particularly in Black individuals, so clinical context matters 5.

Critical Pitfalls to Avoid

• Do not diagnose hypertension based on a single office visit unless BP is severely elevated (≥160/100 mm Hg) 1
• Do not skip out-of-office confirmation before starting treatment, as this prevents overdiagnosis of white-coat hypertension 1, 2
• Do not use urine dipstick alone for albuminuria screening; use albumin-to-creatinine ratio for superior sensitivity 4
• Do not overlook secondary causes in young patients (<30 years), as prevalence is higher than in older adults 4, 5
• Do not skip the ECG even in young patients, as it detects left ventricular hypertrophy and arrhythmias that influence management 4