How do I diagnose hypertension in a patient according to NICE CKS?

Diagnosing Hypertension According to NICE CKS

Hypertension diagnosis requires multiple blood pressure measurements taken on separate occasions, with at least 2 readings per visit over 2-3 visits, and should be confirmed with out-of-office blood pressure monitoring whenever possible. 1

Office Blood Pressure Measurement Technique

Patient Preparation

• Have the patient sit quietly in a chair with feet flat on the floor and back supported for at least 5 minutes before measurement 1
• The patient must avoid caffeine, exercise, and smoking for at least 30 minutes before measurement 1
• Ensure the patient has emptied their bladder 1
• Neither patient nor observer should talk during the rest period or measurement 1
• Remove all clothing covering the cuff placement location 1

Measurement Protocol

• Use a validated automated oscillometric upper-arm cuff device (lists available at www.stridebp.org) 1
• Support the patient's arm at heart level (midpoint of sternum) 1
• Use the correct cuff size—the bladder must encircle 75-100% of the arm circumference 1
• At the first visit, measure BP in both arms simultaneously if possible 1
• Use the arm with the higher reading for all subsequent measurements 1
• If there is a consistent difference >10 mmHg between arms, use the higher arm; if >20 mmHg, consider further investigation 1

Number of Readings

• Take 3 measurements with 1 minute between each reading 1
• Calculate the average of the last 2 measurements 1
• If the first reading is <130/85 mmHg, no further measurement is required at that visit 1
• Separate repeated measurements by 1-2 minutes 1

Diagnostic Thresholds

Office Blood Pressure

• Hypertension is diagnosed when office BP is ≥140/90 mmHg on at least 2-3 separate visits 1
• If BP is only slightly elevated (140-159/90-99 mmHg), obtain measurements over several months 1
• If BP is markedly elevated (≥160/100 mmHg) or there is evidence of organ damage or high cardiovascular risk, measurements can be obtained over shorter periods (weeks or days) 1
• In severe cases (BP ≥180/110 mmHg with evidence of cardiovascular disease), diagnosis can be made on a single visit 1

Out-of-Office Confirmation

• Confirm the diagnosis with home BP monitoring or 24-hour ambulatory BP monitoring whenever possible 1
• Home BP ≥135/85 mmHg confirms hypertension 1
• 24-hour ambulatory BP ≥130/80 mmHg confirms hypertension 1
• Out-of-office measurements are more reproducible than office measurements and more closely associated with target organ damage and cardiovascular risk 1

Home Blood Pressure Monitoring

When to Use

• Recommended for confirming the diagnosis in all patients with elevated office BP 1
• Essential for identifying white coat hypertension (elevated office BP but normal home BP) 1
• Useful for detecting masked hypertension (normal office BP but elevated home BP) 1

Technique

• Use a validated automated oscillometric device 1
• Take measurements in the morning and evening 2
• Record multiple readings over several days 2
• Patient education is essential for proper technique 2

24-Hour Ambulatory Blood Pressure Monitoring

When to Use

• Recommended for initial diagnosis of hypertension when available 1
• Critical for confirming true resistant hypertension and excluding pseudo-resistant hypertension 2
• Essential for detecting nocturnal hypertension and assessing circadian BP patterns 2
• Useful for evaluating white coat hypertension 1

Advantages

• Provides comprehensive information on daytime, nighttime, morning, and 24-hour BP 2
• Correlates more closely with hypertension-related organ damage than office BP 1
• More strongly related to cardiovascular outcomes than office BP 1

Special Circumstances

Standing Blood Pressure

• Measure standing BP after 1 minute and again after 3 minutes in: 1
  • All treated hypertensive patients at follow-up visits
  • Patients with symptoms suggesting postural hypotension
  • Elderly patients at first visit
  • Patients with diabetes at first visit

Severe Hypertension

• If BP is ≥180/110 mmHg with evidence of cardiovascular disease, diagnosis can be confirmed at a single visit 1
• If BP is ≥160/100 mmHg with evidence of organ damage or very high cardiovascular risk, measurements over days rather than months are appropriate 1

Common Pitfalls to Avoid

• Do not diagnose hypertension based on a single office reading unless BP is ≥180/110 mmHg with cardiovascular disease 1
• Do not use measurements taken while the patient is sitting or lying on an examining table—these do not fulfill proper criteria 1
• Do not allow conversation during measurement, as this causes white coat hypertension 3
• Do not rely solely on office BP without out-of-office confirmation, as this leads to misdiagnosis and mistreatment 2
• Do not use unvalidated devices—accuracy must be verified 1

Documentation

• Record both systolic and diastolic BP to the nearest even number 1
• Note the time of most recent BP medication taken before measurements 1
• Provide patients with their BP readings both verbally and in writing 1
• Document which arm was used and any significant inter-arm difference 1