What are the European Society of Hypertension (ESH) recommendations for out‑of‑office blood‑pressure monitoring, including preferred use of ambulatory blood‑pressure monitoring (ABPM) versus home blood‑pressure monitoring (HBPM), measurement protocols, and diagnostic thresholds?

ESH Guidelines for Blood Pressure Monitoring

Office BP Measurement Protocol

The ESH recommends taking 3 office BP readings, with additional readings when the first 2 differ by ≥10 mm Hg or when BP is unstable due to arrhythmia, recording the average of the last 2 readings. 1

• Patients must rest quietly for 3-5 minutes before measurement in a comfortable temperature room. 2
• Patients should empty their bladder and avoid smoking, coffee, or exercise for 30 minutes prior to measurement. 2
• Only validated electronic upper-arm cuff devices with appropriate cuff size should be used. 2, 3
• Heart rate should also be recorded during BP measurements. 1

Confirmation of Hypertension Diagnosis

Hypertension diagnosis requires confirmation by either repeated office readings at several visits OR out-of-office BP measurements (ABPM or HBPM). 1

By Office BP Range:

BP ≥180/110 mm Hg:

• Out-of-office confirmation is not required—start antihypertensive therapy promptly within one week after ruling out hypertensive emergency. 2
• Delaying treatment while awaiting ABPM/HBPM increases cardiovascular event rates. 2

BP 160-179/100-109 mm Hg:

• Confirmation with ABPM or HBPM within 1 month is recommended before initiating therapy. 2

BP 130-159/80-99 mm Hg:

• ABPM or HBPM is strongly recommended to exclude white-coat hypertension prior to drug initiation. 2, 4

Out-of-Office BP Monitoring: ABPM vs HBPM

Both ABPM and HBPM are complementary methods that provide somewhat different information; they should not be regarded as competitive or alternative approaches. 1

When ABPM is Preferred:

• ABPM provides stronger prognostic evidence for cardiovascular outcomes and mortality than office BP alone. 2
• Nighttime BP readings obtained by ABPM are the strongest predictor of cardiovascular events. 2
• ABPM is the reference standard for confirming hypertension diagnosis according to international consensus. 2
• ABPM identifies nocturnal dipping patterns and records BP during real-life activities and sleep. 2
• Office BP has lower specificity than ABPM for detecting true hypertension. 2

When HBPM is Preferred:

• HBPM is more practical for long-term follow-up and monitoring treatment response. 2
• HBPM devices are more widely available and less costly. 2
• HBPM can be performed over multiple days, yielding longitudinal data that improve treatment assessment. 2

Agreement Between Methods:

• Approximately 15% of patients show diagnostic disagreement between ABPM and HBPM, with roughly 50% representing clinically significant differences (>5 mm Hg). 2
• The correspondence between ABPM and HBPM measurements is fair to moderate. 1

ABPM Measurement Protocol

ABPM should be performed over 24-25 hours with measurements taken every 15-30 minutes during daytime and every 30-60 minutes overnight. 1, 2

• At least 70% of recorded readings must be usable for a valid study. 1, 2
• At device fitting, the difference between initial values and operator measurements should not exceed 5 mm Hg; if larger, the cuff must be refitted. 1
• Patients must keep a diary documenting activities, medication intake, sleep periods, and symptoms. 1, 2
• Patients should engage in normal activities but refrain from strenuous exercise, and at cuff inflation must stop moving/talking and keep the arm still at heart level. 1
• Raw values should be reviewed for outliers before calculating mean pressures. 2
• Only grossly incorrect readings should be deleted; if sufficient measurements exist, editing is unnecessary. 1

HBPM Measurement Protocol

HBPM should be performed by measuring twice daily for 7 days, taking 2 readings each time separated by 1-2 minutes, discarding day 1 readings and averaging all remaining measurements. 2, 5

• Only validated automated oscillometric HBPM devices should be used, as many retail devices lack proper calibration. 2, 3
• Devices must be validated according to international standardized protocols and properly maintained with regular calibration at least every 6 months. 1
• The validation status can be obtained on dedicated websites. 1
• Patients require appropriate training under medical supervision with verbal and written instructions. 1

Diagnostic Thresholds

ESH diagnostic thresholds for hypertension are: 1, 2

Measurement Type	Systolic (mm Hg)	Diastolic (mm Hg)
Office BP	≥140	and/or ≥90
24-hour ABPM	≥130	and/or ≥80
Daytime ABPM	≥135	and/or ≥85
Nighttime ABPM	≥120	and/or ≥70
Home BP	≥135	and/or ≥85

Detection of White-Coat and Masked Hypertension

Out-of-office BP measurements are essential to recognize both masked and white-coat hypertension. 1

White-Coat Hypertension:

• Defined as elevated office BP (≥140/90 mm Hg) but normal out-of-office BP (<135/85 mm Hg for HBPM or daytime ABPM). 6
• Requires lifestyle modifications and close follow-up with repeat ABPM in 6-12 months. 6
• Approximately 30-40% progress to sustained hypertension within 5-10 years. 6

Masked Hypertension:

• Defined as normal office BP (<140/90 mm Hg) but elevated out-of-office BP (≥135/85 mm Hg for HBPM or daytime ABPM). 4
• Carries cardiovascular risk equivalent to sustained hypertension and requires antihypertensive treatment. 4
• Screen patients with office BP 120-139/75-89 mm Hg, particularly those with alcohol consumption, obesity, diabetes, or chronic kidney disease. 4

Key Measurement Principles

• Office BP is usually higher than ambulatory and home BP, with the difference increasing as office BP increases. 1
• The reproducibility of out-of-office BP measurements is reasonably good for 24-hour, day, and night BP averages but less for shorter periods and derived indices. 1
• Devices should be validated according to the AAMI/ESH/ISO Universal Standard (ISO 81060-2:2018). 7
• Measurements may not be accurate when cardiac rhythm is markedly irregular. 1

Common Pitfalls to Avoid

• Never delay treatment in patients with BP ≥180/110 mm Hg while waiting for out-of-office confirmation—this increases cardiovascular risk. 2
• Do not rely solely on office BP measurements in high-risk patients without out-of-office confirmation. 4
• Ensure HBPM devices are validated, as many consumer-grade devices lack proper calibration. 2, 3
• Do not assume normal office BP equals low cardiovascular risk without screening for masked hypertension in appropriate patients. 4
• Avoid using excessive intervals between ABPM readings, as this reduces accuracy of 24-hour BP estimates. 1