What is Hypertension (High Blood Pressure)?

Hypertension is defined as elevated blood pressure and is the leading cause globally of death and disability. It is the major risk factor for heart attack and stroke, and is also a significant risk factor for for chronic kidney disease and chronic heart failure. Because individuals with hypertension usually don’t have any symptoms, it is a disease that is often under-diagnosed. Diagnosis relies upon routine blood pressure screening to monitor and detect affected individuals.


 In 2000, it was estimated that nearly one billion individuals worldwide were hypertensive. This figure equates to approximately 26.4% of the total global adult population.
The Australian Diabetes, Obesity and Lifestyle Study (AusDiab) conducted in 1999–2000 reported that 30% of Australians (32% of males and 27% of females) over 25 years of age, or 3.7 million Australians, were hypertensive (blood pressure > 140/90 mmHg).
In general, males are more likely to have hypertension than females, except for between the ages of 45 and 64, when females are at equal risk to males.
The incidence of hypertension is three times higher in Indigenous Australians compared to non-indigenous Australians.

Risk Factors

Approximately 95% of hypertension cases are classified as essential or primary hypertension, in which the underlying cause is unknown. The remaining cases are classified as secondary hypertension, in which there is an identifiable cause (e.g. renal artery stenosis).
Major studies have identified the following factors as key predisposing factors for hypertension:

Factors that have been identified in the Australian 2008 National Heart Foundation Hypertension Guidelines include:

  • Sedentary lifestyle;
  • Smoking;
  • Waist measurement > 94 cm in men and 80 cm in women, or BMI > 25;
  • High dietary salt intake; and
  • Alcohol consumption.


If hypertension remains uncontrolled, it ultimately leads to end organ damage. Hence, uncontrolled hypertension is the major risk factor for coronary artery disease and stroke – two important endpoints in the disease process.
Similarly, chronic renal failure, diabetes, eye disease, erectile dysfunction and chronic heart failure are also significant diseases associated with the progression of uncontrolled or poorly controlled hypertension.


Most people with hypertension are unaware that they have a problem. This is because hypertension has few, if any symptoms. Therefore, primary hypertension is usually detected through routine screening when visiting a GP. Longterm uncontrolled hypertension is associated with an increased risk of heart attack and stroke, amongst other diseases.

Clinical Examination

Hypertension is assessed via the measurement of blood pressure. A diagnosis of hypertension can be made if, after several readings on separate occasions, an elevated value is consistently recorded.
As a guide, a blood pressure reading greater than 140/90 taken on three different occasions is sufficient to diagnose hypertension.  Ambulatory blood pressure monitoring can also be used to assess average blood pressure readings over a 24 hour period.
In addition to blood pressure measurement, a full cardiovascular exam should be performed, noting any signs of an enlarged heart or arterial disease. Additional examinations that should be included if hypertension is suspected include an eye exam, waist circumference and body mass index.
For more information, see blood pressure investigation.

Blood Pressure Calculator
This risk assessment tool is based on data from the National Heart Foundation´s Guide to management of hypertension 2008. It puts your blood pressure measurement into one of the seven diagnostic categories specified in this guide.
Age years
Gender Male / Female
Blood pressure* / mmHg
*Use current blood pressure, regardless of whether the person is on antihypertensive therapy.


Your blood pressure should be rechecked within 2 years or earlier depending on your risk of developing cardiovascular disease. Your General Practitioner can advise you about this risk and also on lifestyle risk reduction.
Your blood pressure is elevated. It should be rechecked within 12 months or earlier depending on your risk of developing cardiovascular disease. Your General Practitioner can advise you about this risk and also on lifestyle risk reduction.
Grade 1 (mild) Hypertension
Your blood pressure is elevated. It should be confirmed within 2 months. Your General Practitioner should advise you about lifestyle risk reduction and/or medication to lower your blood pressure.
Grade 2 (moderate) Hypertension
Your blood pressure is elevated. It should be confirmed within 1 month and you may also need to see a specialist in this time. Your General Practitioner can advise you about lifestyle risk reduction and/or medication to lower your blood pressure.
Grade 3 (severe) Hypertension
Your blood pressure is elevated. It should be confirmed within 1 week and you may also need to see a specialist in this time. Your General Practitioner can advise you about lifestyle risk reduction and/or medication to lower your blood pressure.
Isolated systolic hypertension
Your systolic blood pressure is elevated. Depending on the level it needs to be confirmed within a certain time (140-159mmHg - 2 months; 160-179mmHg - 1 month; >180mmHg - 1-7 days).You may also need to see a specialist. Your General Practitioner can advise you about lifestyle risk reduction and/or medication to lower your blood pressure.
Isolated systolic hypertension with widened pulse pressure
Your blood pressure is elevated. It should be confirmed within 1 week and you may also need to see a specialist in this time. Your General Practitioner can advise you about lifestyle risk reduction and/or medication to lower your blood pressure.
Your blood pressure is lower than normal. Your General Practitioner will ask you about symptoms that you may be experiencing and determine if you require treatment or further investigation.

  1. National Heart Foundation of Australia. Guide to Management of Hypertension 2008- Assessing and Managing Raised Blood Pressure in Adults. Updated 2010. [cited 3 December 2014] Available from: http://www.heartfoundation.org.au/SiteCollectionDocuments/HypertensionGuidelines2008to2010Update.pdf

This information will be collected for educational purposes, however it will remain anonymous.

How is it Diagnosed

Some investigations that may be ordered to assist with diagnosis include:

  • Dipstick urinalysis for blood and protein;
  • Urinalysis: Spot urine albumin/creatinine ratio
  • Blood tests: Urea and electrolytes, lipid profile and fasting blood sugar.
  • ECG: To assess for heart enlargement.

More specific investigations may also be required, including:

  • Renal artery duplex ultrasoundto exlude renal disease if suspected;
  • Renal CT angiography to look for renal artery stenosis;
  • Echocardiogarphy to assess for an enlarged heart;
  • Carotid Doppler; and
  • Plasma aldosterone/renin ratio.


Hypertension at 50 years of age is associated with a 5 year reduction in life expectancy. If hypertension is properly controlled, the risk of stroke reduces by more than the risk of heart attack.


HypertensionThe decision about how and when to intervene with hypertension is dependent upon the severity of the diagnosis, the absolute cardiovascular risk profile and the evidence of end organ damage.

Immediate medical intervention

Immediate treatment is required with any of the following:3,15,16,19

  • Severe hypertension;
  • Evidence end organ damage (regardless of blood pressure);
  • Diabetes where BP > 140/90 mmHg;
  • High absolute cardiovascular risk measurement; and
  • Indigeneity.

Lifestyle modification

In all circumstances, the first management step is lifestyle modification, focusing on:

  • Regular physical activity (minimum 30 minutes a day moderate intensity);
  • Smoking cessation;
  • Dietary modification (salt intake < 4 g/day, plenty of fruit and vegetables, low fat);
  • Weight and waist reduction (aim for BMI < 25, waist < 94 cm (men), 80 cm (women)); and
  • Limit or avoid alcohol (one standard drink per day).


Four major classes of drug are routinely used:

  • Diuretics (especially thiazide diuretics);
  • Angiotensin converting enzyme inhibitors and the related angiotension II receptor blockers;
  • Calcium channel blockers; and
  • Beta-blockers.

All of the drug classes appear to have similar short and medium term protective effects, however, issues of tolerability may lead to beta-blockers being considered a second line medication.
Most drugs take 4–8 weeks for maximum effect. Thus, it is recommended that a minimum period of 6 weeks is trialled before changes to medications are made.Generally treatment starts with a single drug. Recent large studies have shown that cheaper, older drugs, are just as effective as newer drugs. If a single drug fails to achieve blood pressure goals, other agents can be added in.

More information

For more information on high blood pressure, including investigations and treatments, as well as some useful animations, videos and tools, see Hypertensions (High Blood Pressure)


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