Hypertension

Updated to include blood pressure meter calibration when conducting home BP monitoring on recommended considerations when taking BP measurements for diagnosis.
Updated to include approach on home monitoring in the "Clinical Approach" section.

Background

Hypertension is an important contributor to cardiovascular disease. The 2022 National Population Health Survey showed an increasing trend in the crude prevalence of hypertension among Singapore residents aged between 18 to 74 years, from 19.8% in 2010 to 37.0% in 2021-2022.¹
Blood pressure category is defined by the highest level of blood pressure (BP), whether systolic or diastolic.²
Treatment decisions are individualised for each patient and based on an assessment of overall cardiovascular risk.

Clinical Approach[3]

Recommended considerations when taking BP measurements for diagnosis:

Allow the patient to sit or lie down for at least 3 minutes before measuring the BP.
Use the correct size BP cuff.
Take an average of 2 seated BP measurements separated by 2 minutes. If the first two readings differ by 5 mmHg or more, further readings should be obtained and averaged.
Repeat BP measurements on at least 2 separate occasions.
Consider ambulatory or home BP monitoring, where appropriate. Do note that ambulatory or home BP readings tend to be lower than Clinic BP readings .
Blood pressure meter calibration should ideally be performed should home BP monitoring be used.

Diagnose hypertension if systolic ≥140 mmHg or diastolic ≥90 mmHg. For home blood pressure monitoring, use 135/85 mmHg as the cut-off for hypertension. Refer to Table 1 for the cut-offs of the different grades of hypertension.
Assess cardiovascular (CV) risk by considering the presence of CV risk factors and any evidence of hypertension-mediated organ damage (HMOD) . The Healthier SG CV risk calculator may be used to estimate the patient's risk of coronary artery disease.
Consider secondary causes for Hypertension .

Table 1: Initial Screening BP (Average of 2 or More Readings)

Systolic BP (mmHg)	Diastolic BP (mmHg)	Category
<130	<85	Normal
130–139	85–89	High-normal BP
140–159	90–99	Grade 1 Hypertension
160–179	100–109	Grade 2 Hypertension
≥180	≥110	Grade 3 Hypertension
≥140	<90	Isolated Systolic Hypertension (graded by systolic cut-offs as above)

Hypertensive emergency

Diagnose if high blood pressure (often >180/110 mmHg) is associated with signs or symptoms of acute end organ damage or dysfunction.

Management[3]

Blood Pressure Treatment Targets

Individualise BP targets according to patient's cardiovascular risk and overall health status; more stringent BP targets can be considered as tolerated by the patient. Do not lower BP below 120/70 mmHg as evidence of benefit beyond this threshold is inconsistent, and the potential for increased risk of side effects can lead to treatment discontinuation.

Table 2: Risk-Based BP Targets

Source: Agency for Care Effectiveness (ACE). Hypertension – tailoring the management plan to optimise blood pressure control. ACE Clinical Guidance (ACG), Ministry of Health, Singapore. 2023.

Table 3: Recommended Treatment Approach

Source: Agency for Care Effectiveness (ACE). Hypertension – tailoring the management plan to optimise blood pressurecontrol. ACE Clinical Guidance (ACG), Ministry of Health, Singapore. 2023.

Lifestyle Interventions

Where resources are available, consider the roles of other primary care team members – nurse counsellors and primary care coordinator.

Regular exercise
Smoking cessation
Weight reduction
Reduction of alcohol intake
Reduction of sodium intake. Refer to High Blood Pressure: Healthy Eating Guide (e.g. Dietary Approaches to Stop Hypertension (DASH) diet)
Reduction of stress

*Please refer to BMI Control and Smoking Cessation Care Protocols for lists of programmes.

Care teams may use the relevant Lifestyle Prescription to help patients understand practical steps they can take to manage hypertension. A copy may be printed for the patient's use.

Pharmacotherapy

a. Where pharmacotherapy is warranted, most patients would benefit from starting with a low dose. Overall, the choice of antihypertensive depends on several considerations, outlined in table 4 below. (Avoid initiating beta blockers (BBs) as first-line monotherapy for BP control unless BB use is expected to have favourable effect on patient comorbidities. BBs may be beneficial for patients who also require heart rate reduction, or have cardiac comorbidities such as stable ischaemic heart disease, chronic heart failure, or atrial fibrillation).

Table 4: Considerations for choosing a first-line antihypertensive class

Source: Agency for Care Effectiveness (ACE). Hypertension – tailoring the management plan to optimise blood pressure control. ACE Clinical Guidance (ACG), Ministry of Health, Singapore. 2023.

b. Starting with dual therapy may be appropriate if a greater reduction in BP is required to reach targets, such as for patients with SBP/DBP ≥20/10 mmHg above target, those with Grade 2 hypertension or higher (clinic BP ≥160/100 mmHg), or those with comorbidities such as DM or CKD who may require more intensive treatment. The benefits and harms of various combinations are highlighted in Figure 1 and Table 5 below.

Figure 1: Possible Combinations for Dual Therapy to Treat Hypertension

Table 5: Drug Combinations to Consider Avoiding

Source: Agency for Care Effectiveness (ACE). Hypertension – tailoring the management plan to optimise blood pressure control. ACE Clinical Guidance (ACG), Ministry of Health, Singapore. 2023.

Recommended Care Components²

Table 6: Recommended Care Components

Recommended Care Components	Minimum Frequency*	Remarks
Blood Pressure Measurement	Twice a year
Weight and Body Mass Index (BMI) Assessment	Twice a year	Keep <23 kg/m² (For Non-Asian population, keep BMI <25 kg/m²).
Kidney Assessment Serum Creatinine and/or estimated Glomerular Filtration Rate (eGFR), and Urine Albumin-Creatinine Ratio (uACR) or Protein-Creatinine Ratio (uPCR)	Annually	If patient also has diabetes mellitus (DM), Angiotensin Converting Enzyme (ACE) inhibitor or Angiotensin Receptor Blocker (ARB) are preferred antihypertensives to slow progression of diabetic nephropathy. Annual screening of: Serum Cr and/or eGFR and uACR in all patients, or uPCR if significant levels of proteinuria
Smoking Assessment	Annually for smokers; Once-off for non-smokers, unless there is a change in smoking habit	Assessment on smoking habits (estimated sticks/day; zero for non- or ex-smoker) and provide smoking cessation counselling where applicable.
Lipid Profile	At baseline	All patients should be stratified for their risk of developing future coronary events.⁵ Targets of treatment should be personalised by levels of risk. Please refer to Care Protocol for Lipid Disorders.
Cardiac Assessment	At diagnosis before initiating medications	Includes baseline ECG.

*More frequently if clinically indicated.

Considerations for Specialist Referral³

Specialists can be consulted for advice, referral and collaborative care at any point, particularly for

Patients with indications for emergency or urgent treatment, e.g., malignant hypertension, hypertensive cardiac failure or other impending complications.
Patients with difficult-to-manage hypertension, e.g., unusually labile BP.
Patients with hypertension with no or incomplete response to multiple medication regimes (three or more i.e. resistant hypertension).
Patients with suspected secondary hypertension, e.g. hypertension with hypokalaemia.
Hypertension in certain patient populations, e.g., pregnant women, young children, patients aged less than 30 years.
Patients with acute or recent cardiovascular complications from hypertension.

GPs may use the CHAS Medical Referral Form to make subsidised SOC referrals and the GPFirst Referral Form for Emergency Department referrals. These can be found on Healthier SG-compatible GP CMS and on the PCDS web-portal.

Data Submission

The following data fields should be documented in GPs' case notes as part of good clinical practice for all patients enrolled to their practice.

Submission of data fields marked with asterisks* is required for subsidy claims and Healthier SG payments.

Diagnosis

Diagnosis*
CDMP Condition(s)*
Diagnosis Year

Blood Glucose

HbA1c (%) or Fasting Plasma Glucose (mmol/L or mg/dL)
Date

Blood Pressure

Systolic BP (mmHg)*
Diastolic BP (mmHg)*
Date*

Lipid Profile

LDL-Cholesterol (mmol/L or mg/dL)
HDL-Cholesterol (mmol/L or mg/dL)
Triglycerides (mmol/L or mg/dL)
Total Cholesterol (mmol/L or mg/dL)
Date

Kidney Assessment

Urine ACR (mg/mmol)* OR Urine PCR (mg/mmol)*
eGFR (ml/min/1.73m2)* OR Serum Creatinine (μmol/L)*
Date*

Weight

BMI (kg/m2), calculated from height*, weight*
Waist circumference (in cm;mandatory to fill if weight is not feasible. Otherwise optional field to fill)*
Weight not feasible (if applicable)*
Date*

Smoking History

Smoking status (Never smoker, Ex-smoker, Current smoker)*
Year started smoking (if smoker)
No. of sticks smoked/day (For never smoker or ex-smoker, input 0)*
State of change: (i) Pre-contemplation, (ii) Contemplation, (iii) Preparation, (iv) Action, OR (v) Maintenance
Fagerstrom Test Score– For patients who are prepared to quit and are actively participating in a structured smoking cessation counselling programme, GPs can consider administering the Fagerstrom test to determine degree of nicotine dependence
Date of Smoking Assessment

Financing

CHAS/PG/MG cardholders who are Healthier SG enrollees can opt to use the Healthier SG Chronic Tier at their enrolled clinic, which provides percentage-based subsidies for a whitelist of drug products sold within the MOH price caps. When making claims, GPs will need to submit the quantities and selling prices for each whitelisted drug product prescribed.

Details on the GP Annual Service Fee for enrollees with hypertension can be found in the Healthier SG Enrolment Programme Agreement.

References