Strategies for improving the treatment and control of hypertension in Japan

Hypertension is one of the important risk factors contributing to cardiovascular diseases, such as stroke, heart failure, and chronic kidney disease [1, 2]. Moreover, hypertension-related diseases have also been associated with nursing care requirements [3]. As such, the burden of hypertension remains one of the major global health care issues. In a progressively aging society such as Japan, the burden of hypertension has become an urgent health care issue for a society that hopes to achieve healthy longevity [4,5,6]. The Japanese Society of Hypertension (JSH) has recently published the Guidelines for the Management of Hypertension JSH 2019 (JSH 2019) [7], an update to their previous guidelines established 5 years ago (JSH 2014). One of the noted features of the JSH 2019 is that it recommends multidisciplinary team-based care (TBC) providers for hypertension management [7, 8]. This proposal is consistent with recent major guidelines on hypertension management. Accordingly, the 2017 American College of Cardiology/American Heart Association guidelines and 2018 guidelines of the European Society of Cardiology and European Society of Hypertension recommend TBC for hypertension management [9, 10]. This review summarizes the current status of hypertension in Japan, highlights the JSH 2019-based strategy for improving the treatment and control of hypertension, and discusses the implementation of the guidelines in real-world clinical settings.

According to the National Surveys of Circulatory Disorders and the National Health and Nutrition Surveys over the past 36 years between 1980 and 2016, the prevalence of hypertension has increased with age. As of 2017, the number of hypertensive individuals in Japan had been estimated to be around 43 million [7]. The rates at which hypertension is being treated and target blood pressure (BP) levels are being achieved among patients receiving antihypertensive medication have been improving over the past 36 years; however, achievement rates of the target BP remain insufficient. Among all hypertensive individuals, the number of those with uncontrolled hypertension (140/90 mmHg or higher) has been estimated to be around 31 million. Among them, 14 million were unaware of hypertension, 4.5 million were aware of hypertension but left it untreated, and 12.5 million had uncontrolled BP despite using antihypertensive medication. The notable advances in hypertension treatment have contributed to lowering BP levels in many hypertensive individuals. However, hypertension remains a major health care concern, with the actual number of uncontrolled hypertension cases possibly owing to various factors including changes in dietary habits, diversifying work patterns, and continuing to increase due to societal aging [7,8,9,10].

Clinical inertia is defined as the failure of health care providers to initiate or intensify treatment based on current guidelines [11]. Close attention has been paid to clinical inertia and nonadherence. Clinical inertia has been suggested to cause uncontrolled BP and eventually increased cardiovascular morbidities and mortalities. Hence, there is a need to clarify the current status of clinical inertia in Japan in order to implement preventive countermeasures. Japanese surveys regarding awareness and use of Guidelines for the Management of Hypertension have shown that most Japanese physicians were familiar with such guidelines and reflected them in their daily practice. However, some physicians use different criteria for diagnosing hypertension or establishing BP targets for treatment [12, 13]. Recently, an online survey examined the gaps between Japanese physicians’ and patients’ perspectives on hypertension education, adherence to lifestyle modifications and antihypertensive medications, and reasons for adherence to treatment [14]. Although ~80% of physicians reported that they provided adequate education to patients regarding the reasons for hypertension treatment, the risk of complications, BP targets, and lifestyle modifications, only 40–50% of the patients reported having received adequate education on hypertension from their attending physicians. Another web-based survey by Yoshida et al. showed that compared to hypertension specialists, general practitioners were less likely to provide adequate guidance on lifestyle modifications, possibly due to their uncertainty and lack of knowledge on guideline recommendations for the management of hypertension [15]. Considering that most hypertensive patients are managed by general practitioners [7], as well as the gaps between Japanese physicians’ and patients’ perspectives regarding the management of hypertension, proper dissemination of the guidelines and hypertension education programs for all health care providers and patients is imperative.

Guidelines recommend multidisciplinary TBC involving physicians, pharmacists, nurses, dietitians, and other healthcare providers for hypertension management [7,8,9,10]. In fact, systematic reviews and meta-analyses have shown that a multidisciplinary TBC promoted better medication adherence and BP control compared to usual care [16,17,18]. A recent systematic review and meta-analysis had demonstrated that a multidisciplinary TBC, which involved interprofessional collaborative practice comprising at least three professions, improved systolic BP, diastolic BP, and hemoglobin A1c levels among adults with diabetes and hypertension [19]. Multidisciplinary TBC models are diverse and include nonphysician-led TBC (i.e., pharmacist-led TBC, or nurse-led TBC) and physician-led TBC. A recent meta-analysis of 100 articles comprising 55,920 hypertensive patients revealed that the most effective strategies of TBC for improving BP control were nonphysician-led TBC assessing the patients’ BP, clinical data and medication titration [20]. Compared with usual care, nonphysician-led TBC resulted in mean systolic BP reductions of −7.1 mmHg, and physician-led TBC resulted in mean systolic BP reductions of −6.2 mmHg [20]. However, multidisciplinary TBC for hypertension management is not widely used in clinical practice in Japan. The dissemination of multidisciplinary TBC may be a crucial implementation strategy to improve BP control in Japan to bridge the gap between evidence and real-world practice to manage hypertension. Expert health care providers, such as nurses, pharmacists, and registered dietitians, play an essential role in the TBC for hypertension management. Therefore, there is a need to cultivate their skillset accordingly. Moreover, there is a need for more opportunities to learn and practice multidisciplinary TBC. The JSH and its affiliated societies have been introducing hypertension and cardiovascular prevention education program and certification for expert health care providers since 2015. Additionally, the updated JSH 2019 recommends multidisciplinary TBC for hypertension management [7, 8]. This helps to initiate and intensify hypertension management.

To implement countermeasures against hypertension for affected groups, high-risk approaches and population strategies based on multidisciplinary collaboration involving government agencies, mass media, industrial organizations, and academia are essential [7, 8, 21]. For instance, government agencies should develop and implement policies related to health education, regulation and promotion of health care, and effective use of health information. Mass media should then serve as the platform for providing and disseminating up-to-date and correct medical information to educate the Japanese people. Meanwhile, industrial organizations should contribute to developing and marketing low-salt processed foods, biomonitoring systems, information and communication technology (ICT), internet of things, and telemedicine system. The academic sector should promote hypertension research, disseminate the research results to society, and train hypertension specialists. The JSH 2019 proposes reasonable approaches combining both population and high-risk strategies based on multidisciplinary collaboration, which are essential for societal health and longevity given their impact on reducing the number of hypertension and hypertension-related cardiovascular diseases (Fig. 1) [7].

Strategies for improving the management of hypertension (reproduced from ref. [7] with permission from the Japanese Society of Hypertension).

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The most fundamental aspect of hypertension treatment in communities is building a partnership between the patients/their families and the health care staff to optimize the sharing of BP practices and feasible plans to achieve BP targets (Fig. 1) [7]. Actions and initiatives at the community level are also essential in maintaining appropriate BP levels of residents with and without hypertension. In Japan, public health nurses who collect information regarding the daily life of residents play an essential role in the maintenance of appropriate BP levels of community residents. In clinical practice, general practitioners and public health nurses can share information on individual patient’s clinical features, such as BP levels, medication adherence, and expected clinical course [7]. Another priority for local communities is to reduce the number of patients with untreated hypertension. Although Japan has excellent public health checkup programs, studies have shown that only half of the residents underwent health checkups in 2016, whereas only 17% received health guidance during the same year [21]. As such, educational campaigns and initiatives reflecting the current situation in communities are certainly needed. Moreover, the combined assessment of health checkup data and health insurance claims data would allow the identification of patients with untreated hypertension and treat those with poor BP control. Interventions for individuals with untreated and uncontrolled hypertension will eventually improve treatment rates and control of hypertension [7].

Existing guidelines emphasize consideration for health-related quality of life (QOL), adherence, and concordance for the treatment of hypertension. Awareness of hypertension may impair a patient’s health-related QOL [22]. While hypertension treatment has been shown to improve health-related QOL [23], the adverse effects of antihypertensive medications can sometimes reduce health-related QOL [24]. Meanwhile, close communication with the attending physicians and the degree of patients’ satisfaction with the medical staff significantly influence the patient’s health-related QOL [25]. Indeed, studies have suggested that low health-related QOL is a significant barrier toward medication adherence [26,27,28]. Peacock et al. had recently shown that low self-report medication adherence was associated with a decline in health-related QOL over 1 year in older adults with hypertension [27]. Another study showed that the physician–pharmacist collaboration in TBC positively impacted health care [16,17,18]. As members of the TBC for patients with hypertension, pharmacists provide medication guidance to patients and resolve drug therapy problems, such as nonadherence and adverse effects [28]. Hence, pharmacists contribute to TBC by improving BP control without compromising health-related QOL [29]. In Japan, pharmacists provide medication guidance as part of insured medical practice.

Medication adherence refers to the patient’s understanding of the disease and the necessity of treatment, which plays a vital role in sustainable medication on a voluntary and active basis. Aside from allowing the achievement of the target BP, medication adherence has been associated with cardiovascular morbidities and mortalities [30, 31]. A systematic review and meta-analysis had shown significant differences in adherence to antihypertensives among various drug classes [32, 33]. Compared to patients prescribed diuretics and β-blockers, the drug classes associated with the lowest medication adherence, those prescribed angiotensin II receptor blockers, and angiotensin-converting enzyme inhibitors were ~1.5–2 times more likely to have high medication adherence [32]. Following the guidance by pharmacists regarding medication improves medication adherence and BP control [34]. In addition, self-monitoring of home BP has been shown to improve medication adherence [35]. Similarly, monitoring out-of-office BP and degree of medication adherence via ICT has also been found to improve adherence to antihypertensives and BP control [36, 37]. Recently, Kario et al. presented the result of the HERB Digital Hypertension 1 (HERB-DH1) pivotal trial, a Japanese multicenter, prospective, open-label, randomized controlled trial of a digital therapeutic application for essential hypertension. Compared with patients in the control group (lifestyle modification alone), patients in the digital therapeutics group (HERB system plus lifestyle modification) demonstrated significantly greater reductions from baseline in 24-h ambulatory, home, and office systolic BP [38]. Concordance involves continuing a therapeutic strategy based on the agreement between a patient and health care providers and on the assumption that the patient has sufficient knowledge and understanding of hypertension and its treatment [39]. Therefore, patients and health care providers need to share awareness regarding hypertension, the objective of hypertension treatment, methods of treatment, benefits/expected adverse effects of treatment, and the medical expenditure needed to achieve adherence and concordance (Table 1) [7].

Regarding lifestyle modifications for hypertension management, reducing salt intake is especially important, considering that salty diets are particularly common in Japan. The JSH 2019 recommends that hypertensive individual reduce their salt intake to <6 g/day [7, 40, 41]. A proactive multidisciplinary collaboration involving the commitment of industrial organizations, government agencies, health care providers, and academia is needed to achieve the goal of salt reduction [40, 41]. Some countries have shown successful strategies for salt reduction. Finland’s intensive program included broad educational efforts and cooperation with the food industry, which involved producing low-salt processed food and placing warning labels on high-salt items [42]. This campaign reduced the population’s daily salt intake by one-third over the past 30 years, resulting in decreased BP levels throughout the country. The Consensus Action on Salt and Health (CASH) in the United Kingdom (UK) also promoted a gradual reduction in salt content across a broad range of food products within the food industry [43]. Notably, the CASH achieved a 15% reduction in daily salt intake per adult over the past 5 years. The reduced salt intake was associated with a decrease in systolic and diastolic BP by 3.0 and 1.4 mmHg, respectively. Moreover, cardiovascular mortality had reduced approximately by 40% across the UK [43]. Given that processed foods, including processed seasonings, are the main source of salt intake in Japan, there is a need to promote a better understanding of the nutritional components on food product labels and the development and marketing of low-salt foods [40, 41]. The JSH’s Salt Reduction Committee has introduced low-salt processed foods on its website to support the reduction of salt intake.

Excess salt intake in Japanese children was documented in 3-year-old [44], 4–5-year old [45], and school-aged children [46]. As children’s urinary salt excretion and sodium-to-potassium ratio are positively associated with those of their guardians, education on the harmful effects of excess salt intake and the importance of salt reduction for children and their parents is essential [40, 41]. Recently, Asakura et al. developed a school-based nutrition education program comprising a 45-min classroom lecture, and a series of homework assignments for children and guardians in Japan [47]. This program improved children’s nutrition knowledge level by 8.7%. Interestingly, the homework, which was aimed at facilitating communication between the children and their guardians, was positively associated with children’s nutrition knowledge [47]. In addition, the effect of health education on salt reduction was revealed in a randomized controlled trial in China [48]. A school-based education program to reduce salt intake in children and their families trial showed that an education program delivered to primary school children as part of the usual curriculum effectively reduces the salt intake in children and their adult family members. The education program significantly curbed salt intake by 1.9 g/day in children and 2.9 g/day in adults over an intervention period. The reduction in salt intake was accompanied by a significant reduction in systolic BP in adults [48]. The JSH announced the “Tokyo Declaration Promoting Salt Reduction by the Japanese Society of Hypertension-the JSH Tokyo Declaration.” The JSH declared to implement six strategies to achieve the target salt intake [40, 41]. Of the strategies, promoting salt reduction for children as a part of dietary education at school is especially crucial for preventing future hypertension and cardiovascular diseases [41].

The gap between the average life expectancy and healthy longevity is one of the most urgent issues in health and welfare in Japan [4]. More than 6 million elderly individuals in Japan required nursing care in 2015, with hypertension-related diseases, such as stroke, dementia, and heart failure, being the major causes [5]. In addition, cardiovascular disease, along with malignant diseases, has remained one of the leading causes of death in Japan [5]. Therefore, the Japanese government has promulgated the Basic Law on measures against stroke, heart disease, and other cardiovascular diseases to promote a healthy lifespan in 2018. At the core of this Basic Law is the act against hypertension. Disseminating and implementing the concepts and recommendations of the JSH 2019 throughout society and in the daily practice of clinics/hospitals is essential for the appropriate management of hypertension. Recently, the JSH developed a “Future Plan” to overcome hypertension [49], which aims to provide the best clinical practices for hypertension management to achieve a lively and happy society. The establishment of a lifetime-care system for individuals with hypertension (medical system), promotion of research in hypertension and embodiment of “Future Medicine” (academic research), and development of a social model for self-controlled BP (social education) are the main components of this plan. Implementing the “Future Plan” also involves disseminating the guidelines for hypertension management across Japan.

Collaborative studies in Asian countries and regions, including Japan, have contributed significantly to hypertension research. For example, the HOPE Asia Network showed that hypertension awareness, treatment, and control rates were generally low in Asia. However, these factors differ among Asian countries and regions [50]. The JSH has made several declarations and commitments, including meetings, while working closely with Asian and Western hypertension societies and sharing learning in a collaborative to combat common hypertension-related problems [49, 51, 52]. The next stage involves creating a network for overcoming hypertension and hypertension-related diseases in Asia [53].

Given the contribution of the guidelines toward the improvement of BP control and reduction in cardiovascular diseases over the past several decades, regular updates that reflect current evidence and advances in antihypertensive therapies are essential. One of the main features of the updated JSH 2019 is its recommendation of multidisciplinary TBC for hypertension management. Additionally, the “JSH Tokyo Declaration” pledged the implementation of six strategies, including education on salt reduction for children and their parents. These help initiate and intensify hypertension management and combat clinical inertia within the Japanese society as well as clinical practice. Furthermore, the “Future Plan” promoted by the JSH would contribute to the dissemination and implementation of JSH 2019. Progress in big data and its utilization for personal health records via ICT will provide a tailored medical approach for each individual and reinforce multidisciplinary collaboration to combat the enormous burden of hypertension and hypertension-related cardiovascular diseases in the future.