Hypertension
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Overview
Care Protocols
Clinical Calculators
Lifestyle Prescriptions
Lifestyle Programmes
GP IT Enablement Grant

​Last updated on 5 June 2023


  1. Hypertension is an important contributor to cardiovascular disease. The 2020 National Population Health Survey showed an increasing trend in the crude prevalence of hypertension among Singapore residents aged between 18 to 74 years, from 24.2% in 2017 to 35.5% in 2019-2020.1

  2. Blood pressure category is defined by the highest level of blood pressure (BP), whether systolic or diastolic.2

  3. Treatment decisions are individualised for each patient and based on an assessment of overall cardiovascular risk.


​Recommended considerations when taking BP measurements for diagnosis:

  1. Allow the patient to sit or lie down for at least 3 minutes before measuring the BP.

  2. Use the correct size BP cuff. 

  3. 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.​

  4. Repeat BP measurements on at least 2 separate occasions.

  5. Consider home BP monitoring, where appropriate.

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.

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

Sy​stoli​c BP (mmH​g) Diastolic BP (mm​​Hg) Cate​gory Rec​ommended Action
<130​ <85 Normal “Normal BP". Advise BP check biennially.
130–139 85–89​ High-normal BP Advise lifestyle modification. Check BP annually or more frequently if cardiovascular risk factors are present.
140–159 90–​99 Grade 1 Hypertension For those without cardiovascular risk factors, try lifestyle modifications first for 3–6 months (shorter for those with cardiovascular risk factors). For those at high risk with established cardiovascular or renal disease, diabetes mellitus (DM) or target organ damage, initiate drug treatment with lifestyle measures at the same time
160–179 100–109 Grade 2 Hype​rtension For those at low risk with 0 to 2 cardiovascular risk factors, can try lifestyle modification first for several weeks; otherwise, initiate drug treatment with lifestyle measures at the same time.
≥180 ≥110 Grade 3 Hypertension Initiate drug treatment with lifestyle measures at the same time.
≥140 <90 Isolated Systolic Hypertension Isolated systolic hypertension is graded according to the same ranges of systolic BP as the above, and the corresponding recommendations apply.


Hypertensive emergency

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


History, examination and investigations

Important Note - determine whether there is/are

  1. Secondary causes for the hypertension 
  2. Target organ damage
  3. Other cardiovascular risk factors present

​
Blood Pressure Treatment Targets

1. General:

  • <140/90 mmHg in patients <80 years old.

  • <150/90 mmHg in patients ≥80 years old (do not decrease diastolic BP to <60 mmHg).

 

2. Special conditions:

  • <140/80 mmHg in patients with diabetes mellitus

  • <130/80 mmHg in patients with proteinuria (both diabetic and non-diabetic patients)

  • <150/100 mmHg in pregnant patients without target organ damage (do not decrease diastolic BP to <80 mmHg)

  • <140/90 mmHg in pregnant patients with target organ damage

The Cardiovascular Disease (CVD) Risk Calculator​ may be used to determine the BP targets of patients.

Table 2. Recommended Care Components

Recomm​end​ed Care ​Compone​nts​ 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/o​r 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​.

Car​diac Assessment At diagnosis before initiating medications Includes baseline ECG.

*More frequently if clinically indicated.


Non-pharmacological3,4

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 Bloo​d 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.


Pharmacological4​​


Figure 1: Drug Choices

Drug Choices for Hypertension.png

Drug Combinations


  1. Beta-blocker + angiotensin-converting enzyme inhibitor (ACE-I)/angiotensin receptor blocker (ARB) does not produce synergistic BP reduction

  2. ACE-I + ARB decrease GFR in patients with chronic kidney disease and should be avoided. (Consider monitoring serum creatinine and potassium levels for all patients started on either ACE-I or ARB)

  3. Beta-blocker + diuretic increase risk of developing DM

  4. Beta-blocker + non-dihydropyridine calcium channel blocker (CCB) (e.g. diltiazem) increase risk of bradycardia and atrioventricular block and should be avoided 

Considerations​ for Specialist Referral2​

Specialist Referral Recommended 
  • Emergency or urgent treatment indicated e.g. malignant hypertension, hypertensive cardiac failure or other impending complications.
  • Hypertension difficult to manage e.g. unusually labile BP, hypertension refractory to multiple (3 or more) drug regimens.
  • Suspected secondary hypertension i.e. hypertension due to an underlying cause, such as hyperaldosteronism.
  • Hypertension in special circumstances e.g. pregnancy, young children.
Consider Specialist Input 
  • Young hypertensive patients who are less than 30 years old.
  • Patients suspected to have secondary causes of 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.


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

  1. Diagnosis*​
  2. Date

Blood Pressure

  1. Systolic BP (mmHg)*
  2. Diastolic BP (mmHg)*
  3. Date*

Blood Glucose

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


Lipid Profile

  1.   LDL-Cholesterol (mmol/L or mg/dL)
  2.   HDL-Cholesterol (mmol/L or mg/dL)
  3.   Triglycerides (mmol/L or mg/dL)
  4.   Total cholesterol (mmol/L or mg/dL)
  5.   Date


Weight

  1. BMI (kg/m2), calculated from height*, weight*
  2. Waist circumference (in cm; optional field to fill)
  3. Date*

Kidney Assessment
  1. Serum creatinine (mol/L)* OR eGFR (ml/min/1.73m2)*
  2. Urine ACR (mg/mmol)* OR Urine PCR (mg/mmol)*
  3. Date* 

Smoking History
  1. Smoking status* [Never smoker, Ex-smoker, Current smoker]
  2. Year started smoking (if smoker)
  3. No. of sticks smoked/day* (if smoker)
  4. State of change: (i) Pre-contemplation, (ii) Contemplation, (iii) Preparation, (iv) Action, OR (v) Maintenance


CHAS/PG/MG cardholders who are Healthier SG enrolees would be eligible for the Healthier SG Chronic Tier, 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 enrolees with hypertension can be found in the Healthier SG Enrolment Programme Agreement.​