Notes on the data: Health risk factors
Estimated population, aged 18 years and over with high blood pressure, 2014-15
Policy context: Hypertension or high blood pressure is persistently high pressure in the arteries that can, over time, cause damage to organs such as the kidneys, brain, eyes, and heart. Factors that increase the risk of developing hypertension include obesity, being sedentary, smoking, excessive intake of alcohol and of salt, and the use of some pharmaceuticals (e.g., oral contraceptives, steroids) and drugs (e.g., cocaine, amphetamines). In many cases, the cause of hypertension is not known. In others, it is due to an identifiable condition such as pregnancy, diabetes, thyroid and kidney disease, and a number of rare tumours and hormone abnormalities.
Respondents to the 2014-15 National Health Survey aged 18 years and over had their blood pressure measured. The number of people with high blood pressure presented in this section are based on these measurements, and do not include people who have high blood pressure but are managing their condition through the use of blood pressure medications.
In 2014-15, 23.0% of all Australians aged 18 years and over (4.1 million people) had measured high blood pressure. This was higher than in 2011-12, when 21.5% of adults had measured high blood pressure. It is also over twice the level of people who reported having hypertension.
Overall, men were more likely to have high blood pressure than women (24.4% and 21.7% respectively), while the proportion of Australians with high blood pressure increased with age. Just under half (46.9%) of all people aged 75 years and over had measured high blood pressure in 2014-15 .
- Australian Bureau of Statistics (ABS). Hypertension and measured high blood pressure, National Health Survey: First Results, 2014-15. Available from: http://www.abs.gov.au/ausstats/abs@.nsf/mf/4364.0.55.001; last accessed 04/12/2016
Notes: In the absence of data from administrative data sets, estimates are provided for selected health risk factors from the 2014–15 National Health Survey (NHS), conducted by the Australian Bureau of Statistics (ABS).
Estimates at the Population Health Area (PHA) are modelled estimates produced by the ABS, as described below (estimates at the Local Government Area (LGA) and Primary Health Network (PHN) level were derived from PHA estimates).
Users of these modelled estimates should note that they do not represent data collected in administrative or other data sets. As such, they should be used with caution, and treated as indicative of the likely social dimensions present in an area with these demographic and socioeconomic characteristics.
The numbers are estimates for an area, not measured events as are, for example, death statistics. As such, they should be viewed as a tool that, when used in conjunction with local area knowledge and taking into consideration the prediction reliability, can provide useful information that can assist with decision making for small geographic regions. Of particular note is that the true value of the published estimates is also likely to vary within a range of values as shown by the upper and lower limits published in the data (xls) and viewable in the bar chart in the single map atlases.
What the modelled estimates do achieve, however, is to summarise the various demographic, socioeconomic and administrative information available for an area in a way that indicates the expected level of each health indicator for an area with those characteristics. In the absence of accurate, localised information about the health indicator, such predictions can usefully contribute to policy and program development, service planning and other decision-making processes that require an indication of the geographic distribution of the health indicator.
The response rate of around 85% provides a high level of coverage across the population; however, the response rate among some groups is lower than among other groups, e.g., those living in the most disadvantaged areas have a lower response rate than those living in less disadvantaged areas. Although the sample includes the majority of people living in households in private dwellings, it excludes those living in the most remote areas of Australia; whereas these areas comprise less than 3% of the total population, Aboriginal people comprise up to one third of the population in these areas. This and other limitations of the method mean that estimates have not been published for PHAs with populations under 1,000, or with a high proportion of their population in:
- non-private dwellings (hospitals, gaols, nursing homes - and also excludes members of the armed forces);
- in very remote or in discrete Aboriginal communities, as determined by the ABS; and
- where the relative root mean square errors (RRMSEs) on the estimates was 1 or more (estimate replaced with ≠)
- Estimates with RRMSEs from 0.25 and to 0.50 have been marked (~) to indicate that they should be used with caution; and those greater than 0.50 but less than 1 are marked (~~) to indicate that the estimate is considered too unreliable for general use.
- For the Primary Health Network (PHN) data, differences between the PHN totals and the sum of LGAs within PHNs result from the use of different concordances.
Information was collected in the National Health Survey using two methods. These were:
- a question on whether respondents had ever been told by a doctor or nurse they had any circulatory conditions (including hypertension or high blood pressure), and
- for adults aged 18 years and over, the taking of blood pressure measurements.
A person was defined as having high blood pressure if their systolic/diastolic blood pressure was equal to or greater than 140/90 mmHg .
These results are based on the latter definition and relate to the 75.7% of respondents aged 18 years and over who had have their blood pressure measured. For those who did not have their blood pressure measured, blood pressure was imputed. For more information see Appendix 2: Physical measurements in the 2014-15 National Health Survey.
- Heart Foundation, 2015, Blood pressure. Available from: http://heartfoundation.org.au/your-heart/know-your-risks/blood-pressure; last accessed 04/12/2016
Numerator: Estimated population with measured blood pressure
Denominator: Total population aged 18 years or over
Detail of analysis: Indirectly age-standardised rate per 100 population; and/or indirectly age-standardised ratio, based on the Australian standard
Source: Compiled by PHIDU based on modelled estimates from the 2014-15 National Health Survey, ABS (unpublished).