Recent guidelines

All recent hypertension guidelines, including those from the Japanese Society of Hypertension (JSH 2019) [253] , European Society of Hypertension/European Society of Cardiology (ESH/ESC 2018) [254] , and the 2017 American Heart Association/American College of Cardiology (AHA/ACC) [178] , recommend the practical use of out‐of‐office BP measurement for the diagnosis and management of hypertension. In particular, the JSH 2019 guidelines strongly recommend a home blood pressure measurement (HBPM)‐guided approach as the first step for the management of hypertension [253] .

There are four different options for measuring blood pressure (BP) available in clinical practice (office BP, automated office BP [AOBP], HBPM, and ambulatory BP monitoring [ABPM]) (Figure 3.1) [180] . Each approach reflects different pressor effects (Figure 3.1) [156, 180] . However, all out‐of‐office BP measurements are superior to routine office BP measurements for predicting cardiovascular events. After achieving a universal BP goal of 130/80 mmHg, the ideal goal of white‐coat effect‐excluding BP may be <125 mmHg.

Diagnosis of masked and white‐coat hypertension

Masked hypertension is defined as normotension based on office BP readings and hypertension based on out‐of‐office BP measurement, while white‐coat hypertension is defined as normotension based on out‐of‐office BP and hypertension based on office BP (Figure 3.2) [37] . Detection of masked and white‐coat hypertension by using the out‐of‐office BP monitoring devices is important to improve the quality of BP control and reduce the cardiovascular event risk (Figure 3.3) [41] . Table 3.1 [37] highlights different office, home, and ambulatory BP value thresholds for the definition of hypertension. The 2017 AHA/ACC guidelines recommend a universal threshold of 130/80 mmHg for office, home, and daytime ABPM (Table 3.2).

Definition of morning hypertension

The broad definition of “morning hypertension” is having an average morning systolic BP (SBP) ≥135 mmHg and/or average morning diastolic BP (DBP) ≥85 mmHg, regardless of office BP (Table 3.3) [24, 38] . In addition, the strict definition of “morning hypertension” includes those with a morning–evening home BP difference (ME‐dif; morning SBP—evening SBP) of ≥20 mmHg [38, 51]. Morning hypertension (ambulatory morning hypertension) can also be diagnosed using ABPM [51] . Masked morning hypertension is defined as morning hypertension when office BP is <140/90 mmHg.

Definition of nocturnal hypertension

Nocturnal hypertension is defined as average nighttime SBP ≥120 mmHg and/or DBP ≥70 mmHg (Table 3.4). Nighttime BP is that measured from bedtime to rising or over the period 1:00 AM to 6:00 AM by ABPM or HBPM (at least three readings per night for at least two days). Office‐masked nocturnal hypertension is defined as nocturnal hypertension with office BP <140/90 mmHg, while morning‐masked nocturnal hypertension is defined as nocturnal hypertension with morning home BP <135/85 mmHg. Isolated nocturnal hypertension is defined as nocturnal hypertension with office BP 140/90 mmHg and morning home BP values <135/85 mmHg.

When to use HBPM and ABPM

Clinical use of HBPM and ABPM increases the quality of hypertension management. HBPM is easily implemented in clinical practice. However, HBPM only measures BP at a specific time (morning and/or evening) and in a specific condition (resting while sitting), while ABPM measures dynamic ambulatory BP changes during the day and nighttime BP during sleep periods. This allows detection of both dynamic nighttime BP changes and masked nocturnal hypertension. Thus, the best clinical practice would include usage of both HBPM and ABPM [181] . Morning BP can be measured using both HBPM and ABPM. HBPM is self‐measured at home while the patient is seated, and ABPM measures BP regularly at 15–30‐minute intervals throughout each 24‐hour period. ABPM used to be the only option for measuring BP overnight, but recent HBPM device design advances mean that nighttime home BP can be measured during sleep. The advantages of HBPM over ABPM include convenience and less discomfort.

HBPM is recommended for all medicated hypertensive patients, those with elevated BP (office SBP 120–129 mmHg and DBP <80 mmHg), or individuals with prehypertension who have an estimated two‐year risk of new‐onset hypertension of ≥40% (calculated by the Genki–Jichi hypertension prediction model [255] (Figure 3.4 and Table 3.5).

ABPM is recommended for high‐risk patients with hypertension who have any of the following: (1) home BP ≥120/80 mmHg; (2) history of cardiovascular events; (3) organ damage (e.g. left ventricular hypertrophy [LVH], albuminuria, N‐terminal pro‐brain natriuretic peptide [NT‐proBNP] level >125 pg/mL); (4) nocturnal hypertension‐suspected comorbidities (sleep apnea syndrome, diabetes, chronic kidney disease [CKD]); or (5) suspected systematic hemodynamic atherothrombotic syndrome (SHATS).

In the Trial of Preventing Hypertension (TROPHY) [256] , the incidence of new‐onset Stage 2 hypertension in patients with Stage 1 hypertension (office BP 130–140/85–90 mmHg) was 40.4% at the two‐year follow‐up, and 63.0% at the four‐year follow‐up. However, the average home BP at baseline was already 134/83 mmHg, indicating that at least half of the subjects already had hypertension diagnosed based on home BP readings. In a recent analysis, subjects with elevated office BP (120–129/<80 mmHg) had >3 times the risk of hypertension than those with normal (optimal) BP (Figure 3.5) [257, 258].