Notes on the data: Chronic diseases and conditions
Estimated population with asthma, 2011-12
Note: The indicators of chronic diseases and conditions have not been updated to reflect information in the 2014–15 National Health Survey. The modelling of these estimates has been held over until a final decision is made as to access by PHIDU to small area data considered to be highly relevant for use as small area predictors in the production of these estimates. For example, for the indicator of diabetes type 2, the MBS item for HbA1c and, for mental health conditions, anti-depressant medications from PBS both add strength to the available predictors. Work will proceed with the current predictors until these data is made available.
Policy context: Asthma is a disorder affecting the small airways of the lungs. People with asthma have sensitive airways that narrow in response to certain "triggers", leading to difficulty in breathing. The airway narrowing is caused by inflammation and swelling of the airway lining, the tightening of the airway muscles, and the production of excess mucus. This results in a reduced airflow in and out of the lungs. At present, the cause of asthma is not known and there is no cure. However, with appropriate management, most people with asthma can lead normal, active lives.
Notes: In the absence of data from administrative data sets, estimates are provided for certain chronic diseases and conditions from the 2011–12 Australian Health Survey, 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).
Estimates for Quintiles and Remoteness Areas are direct estimates, extracted using the ABS Survey TableBuilder.
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 survey 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 areas;
- in discrete Aboriginal communities; 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.
In the AHS, these data refer to persons ever told by a doctor or nurse that they have asthma, and whose asthma is current and long-term. Whether a person's asthma is current or not was determined by whether they had had any symptoms of asthma or taken treatment for asthma in the last 12 months. A long-term condition is defined as a condition that is current and has lasted, or is expected to last, for 6 months or more.
Numerator: Estimated number of people with asthma as a current, long-term condition
Denominator: Total population
Detail of analysis: Indirectly age-standardised rate per 100 population; and/or indirectly age-standardised ratio, based on the Australian standard
PHA, LGA & PHN: Compiled by PHIDU based on modelled estimates from the 2014-15 National Health Survey, ABS (unpublished).
Quintiles & Remoteness: Compiled by PHIDU based on direct estimates from the 2011-12 Australian Health Survey, ABS Survey TableBuilder.