Asian management of hypertension: Current status, home blood pressure, and specific concerns in Singapore

Abstract

Despite reductions in hypertension prevalence and improvements in control rates in recent years, almost one‐third of all deaths in Singapore are due to cardiovascular disease and that proportion is growing. Ischemic heart disease is the most common cause of cardiovascular death, ahead of stroke. Local data suggest that awareness and support for home blood pressure monitoring (HBPM) is good, but there are reservations about the accuracy of HBPM devices and physicians cited a lack of time and resources to educate patients about HBPM. In addition, there was a knowledge gap around use of HBPM for evaluating treatment response. This is consistent with the emphasis of using HBPM for the diagnosis, rather than monitoring, of hypertension in the Singapore hypertension guidelines. In the absence of specific HBPM thresholds and targets, it is suggested that HOPE Asia Network consensus documents provide the most locally relevant guidance of the use of HBPM. Calcium channel blockers and angiotensin receptor blockers are the most commonly used antihypertensive agents in Singapore, and monotherapy was relatively uncommon (24%) of patients. Overall, more needs to be done in detecting and managing hypertension in Singapore to address rates of cardiovascular disease and cardiovascular disease mortality. Use of HBPM needs to be encouraged to improve adherence to treatment and optimize BP targets according to Asian perspectives and data.

1. CARDIOVASCULAR DISEASE INCIDENCE AND HYPERTENSION MANAGEMENT IN SINGAPORE

The Singapore National Health Survey (NHS) 2010 showed that the crude prevalence of hypertension among Singapore residents aged 30‐69 years was 23.5%, compared with 24.9% in 2004 and 27.3% in 1998. Of those aged 18‐69 years, almost one in five residents (18.9%) had hypertension in 2010.1 The proportion of known hypertensive patients with good blood pressure (BP) control (defined as BP < 140/90 mm Hg) was 67.4%, compared with 49.5% in 2004, while the proportion with good control among those receiving treatment was 69.1%, compared with 52.9% in 2004.1

In 2017, there were 6292 deaths from cardiovascular disease (CVD) in Singapore (30.1% of all deaths). This means that one of every three deaths each year in Singapore is due to heart diseases or stroke, and 17 people die every day. These figures represent an increase from 2016 (29.5% or 5905 deaths) to 2015 (29.6% or 5879 deaths). Ischemic heart disease is more common than stroke in Singapore (crude incidence rates of 321.4 vs 222.1 per 100 000 population in 2016).2, 3 Rates of both forms of cardiovascular disease have increased over time. Based on 2016 data, the top five risk factors present in stroke patients were hyperlipidemia (83.5%), hypertension (82.8%), ischemic heart disease (47.5%), diabetes mellitus (43.0%), and smoking (37.3%).2

2. CURRENT STATUS OF HBPM IN THE MANAGEMENT OF HYPERTENSION IN SINGAPORE

Monitoring of morning home BP using home BP monitoring (HBPM) will likely be necessary to facilitate achievement of lower BP targets. However, recent local survey data showed that Singaporean physicians had reservations about the accuracy of HBPM devices and cited limited time and resources in their clinical practice to educate their patients about using HBPM.4 Although most clinicians would recommend HBPM, there seems to be a knowledge gap in how to do HBPM and evaluating treatment response; there was also no consensus in home BP targets.4 This is not unexpected because the Singapore hypertension guidelines5 mostly emphasize use of HBPM for the diagnosis of hypertension rather than for evaluating BP control and guiding changes in antihypertensive therapy.

3. SINGAPORE SUB‐ANALYSIS OF THE ASIABP@HOME STUDY

Recently, a multinational Asian specialty center study investigating performance measures relating to home and clinic BP control was published (the AsiaBP@Home study).6, 7 Singapore data from the AsiaBP@Home study (n = 99) showed that 57% of patients had uncontrolled hypertension using the 2017 American College of Cardiology (ACC)/American Heart Association (AHA) thresholds,8 an increase of 23% over values obtained using the conventional thresholds (Figure 1). The proportion of patients with well‐controlled clinic/home BP was 37%/59% with conventional thresholds, vs 14%/42% with new thresholds (Figure 1). Interestingly, there was no change in the proportion of patients with white‐coat hypertension when the lower thresholds were used; in contrast, the rate of masked hypertension decreased to only 1% (Figure 1). These data suggest that targeting more patients for further BP lowering (ie, the 23% of patients who were previously categorized as having controlled BP) may expose more patients to risk of unnecessary treatment. On the other hand, diagnosing and treating to lower targets may improve the current cardiovascular risk in Singapore.

Figure 1.

Distributions of blood pressure (BP) control status based on different clinic and morning home BP thresholds in the Singapore sub‐analysis from the AsiaBP@Home study. Left panel represents the results based on cutoff values of 140 mm Hg for clinic systolic BP (SBP) and 135 mm Hg for home SBP. Right panel represents the results based on cutoff values of 130 mm Hg for both clinic SBP and home SBP

4. POSITIONING OF HBPM IN THE SINGAPORE HYPERTENSION GUIDELINES

Consistent with HOPE Asia Network guidance,9, 10, 11 the Singapore hypertension clinical practice guidelines5 recommend the use of HBPM in hypertension care. These guidelines also state that both the diagnostic and therapeutic thresholds of home BP measurements are 135/85 mm Hg, which are considered equivalent to 140/90 mm Hg in office BP. However, when office BP is to be controlled intensively, there is no recommended home BP target equivalent. If we aim for lower BP targets in high‐risk patients, it may be more appropriate to include home BP rather than office BP. It is most important that use of HBPM becomes more popular and widespread, and routinely used when trying to set the target office BP below 130/80 mm Hg. Regardless of office BP targets, it has been suggested that home BP should be lowered to 125 mm Hg in a three‐step approach to minimize CVD risk.10 Thus, in the absence of specific local guidelines, the most relevant guidance is provided by the current HOPE Asia Network documents.10, 11

5. TRADITIONAL ANTIHYPERTENSIVE THERAPY AND POPULAR ANTIHYPERTENSIVE DRUGS IN SINGAPORE

The 2018 Singapore hypertension guidelines recommend the use of calcium channel blockers (CCBs), angiotensin‐converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), β‐blockers, and diuretics as key antihypertensive agents. A sub‐analysis of Singapore data from the AsiaBP@Home study showed that CCBs were the most commonly used antihypertensives (74%), followed by ARBs (64%), ß‐blockers (29%), and diuretics (22%). Only 24% of patients were receiving monotherapy, most were receiving dual antihypertensive therapy (47%; usually a CCB plus a ARB or ACE inhibitor), and 29% were being treated with three or more antihypertensive medications.

6. SPECIFIC CONCERNS AND PERSPECTIVES FOR HYPERTENSION MANAGEMENT IN SINGAPORE

Unfortunately, CVD and CVD mortality rates in Singapore have remained virtually unchanged over recent years. This suggests that more can be done in the management of hypertension, particularly increasing awareness and treatment to improve the BP control rate in treated patients using both office and home BP measurements. Use of HBPM needs to be encouraged to improve adherence to treatment and optimize BP targets according to Asian perspectives and data.

CONFLICT OF INTEREST

JC Tay has received advisory board and consultant honoraria from Pfizer. BW TEO has received honoraria for lectures and consulting fees from Astellas, AstraZeneca, Boehringer Ingelheim, Servier, MSD, and Novartis.

Tay JC, Teo BW. Asian management of hypertension: Current status, home blood pressure, and specific concerns in Singapore. J Clin Hypertens. 2020;22:508–510. 10.1111/jch.13782