Australian Bureau of Statistics
4363.0.55.001 - Australian Health Survey: Users' Guide, 2011-13
Latest ISSUE Released at 11:30 AM (CANBERRA TIME) 07/12/2012
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LONG-TERM HEALTH CONDITIONS
Information was obtained for all persons in the NHS survey.
Long-term condition data is drawn from two conceptually different sets of data:
Data from these two groups are combined into a condition status relating to long-term conditions or persons with long-term conditions, in the following output categories:
2. Ever told has condition, still current but not long-term.
3. Ever told has condition, not current.
4. Not known if ever told or not ever told, but condition current and long-term.
5. Never told, not current or long-term.
Specific condition modules
The 2011-12 NHS collected information on the prevalence of some long-term conditions in the Australian population via specific modules enabling particular questions to be asked about people with those conditions. Those conditions included those classified as National Health Priority Areas as well as sight and hearing. The National Health Priority Area conditions were:
The prevalence of these conditions was established though the collection of supplementary information to determine whether a reported condition was current and long-term. Some conditions such as sight and hearing were assumed to be current and/or long term. This is discussed in more detail in the individual sections later in this chapter.
Long-term conditions module
Initial data for other long-term conditions was collected via a prompt card showing the following conditions. Respondents were asked whether they currently had any of these conditions, and whether they had lasted or were expected to last for six months or more:
More than one response was allowed.
Respondents who reported having a food or drug allergy were asked whether their reaction to food or drugs is:
An anaphylactic reaction is a severe form of allergic reaction which may be life threatening. It may affect the skin, respiratory system, gastrointestinal system and cardiovascular system. The anaphylactic reaction can be brought on by an allergy to certain foods, or the use of certain drugs or herbal medicines.
Respondents were then asked to report any other conditions (not included on the previous list or reported earlier in the survey) that had lasted or were expected to last six months or more. There was capacity to report up to six other conditions. If more than six conditions were identified the six main conditions were recorded.
Respondents were then finally asked whether they had any other long-term conditions such as the following:
More than one response was allowed.
For respondents who identified here that they had asthma, cancer, diabetes/high sugar levels, heart and circulatory disease, kidney disease, arthritis or osteoporosis, depending on question wording, an edit was triggered if they had not previously responded to their related module. Interviewers were then able to return to that module and complete it or progress to the question regarding whether they had ever been told by a doctor or nurse that they have that condition. This enabled most of these cases to be appropriately classified to a condition status which was derived for all conditions. If this edit was not triggered then diagnosis status was identified as not known and specific module questions were not answered.
Mental Health Conditions
Respondents who identified in this module having specific mental health conditions were asked an additional set of questions for each condition up to a limit of 6 conditions. These questions included:
Respondents were then asked (whether or not they had been diagnosed) whether they had taken any of the following medications in the last two weeks for any of their conditions:
How long they had been taking each type of medication for:
The frequency they took each type of medication:
Respondents with a diagnosed mental health condition were then sequenced to the "Actions" module where they were asked questions about the number of times they had seen a GP, specialist etc. for their mental health condition.
Conceptually, cases of mis-diagnosis are excluded. Where interviewers became aware of a condition which the respondent had been told they have, but that diagnosis later proved incorrect, the respondent was recorded as not ever told they have the condition. This approach retains the conceptual alignment between the 'ever told' and 'whether current' populations. However, respondents may not have made this known to interviewers, with the result being that those cases will appear in survey results as 'ever told' but 'not current'.
The 2011-12 NHS questionnaire design enabled a theoretical maximum of 100 conditions per person to be reported. While the survey questionnaires were designed to prompt respondents and give them an opportunity to report all their long-term conditions, whether or not they chose to report a condition to the ABS interviewer, and how they chose to identify or describe that condition, was at the respondent's discretion.
INFORMATION ABOUT MEDICAL CONDITIONS
Classification of conditions
Provision was made on the survey questionnaires for interviewers to record condition information in two ways:
Information from both sources was combined and classified to a single list of approximately 1000 specific condition and condition group categories (referred to as the "1000 input code list" in this publication). This list covers the more common types of long-term conditions experienced in the Australian community. The list was initially developed by the Family Medicine Research Centre at the University of Sydney, in consultation with the ABS, for the 2001 NHS. A computer-based coding system was developed by the ABS based on this list, and interviewers were able to select from it using a trigram coder which was built into the CAI instruments. Predefined response categories in the questionnaires were allocated unique codes within the 1000 input code list.
Results from the survey are generally not available classified to the most detailed condition level based on ICD10. As the data are from a sample survey, there are not enough observations to support reliable estimates at that level of detail. While some data at this level may be made available on request for more commonly occurring conditions, for general output purposes, long-term conditions are classified based on the 10TH REVISION OF THE INTERNATIONAL CLASSIFICATION OF DISEASES (ICD10). Refer to Appendix 2: Classification of medical conditions for the conditions classifications and codes used in the AHS.
The output classification was developed by the ABS based on mapping between the 1000 input code list and ICD10 provided by the Family Medicine Research Centre. The classification takes into account:
Efforts were made to ensure that the description of each condition which was recorded at interview was as precise and informative as possible, to enable detailed, accurate and consistent coding of conditions, where the precise condition name wasn't known at the time of the interview. Copies of the standard classifications of medical conditions available from this survey are contained in Appendix 2: Classification of medical conditions of this Users' Guide. The process of mapping the 1000 input codes to the ICD10 output classifications was complex, and in some cases the classification of the input codes was based on 'best fit' rather than 'exact match'.
Points to be considered in interpreting data for this topic include the following:
COMPARABILITY TO 2007-08
Changes in community perceptions of illness and disability, together with changes in the identification and treatment of conditions (e.g. institutional versus community care) may have affected the degree to which certain conditions were reported in the survey.
The prevalence of most long-term illness increases with age. In drawing comparisons of prevalence between the surveys, account should be taken of the shift in the age profile of the Australian population during the period between surveys. As a result of this, Table 1 in this product has been age standardised so that direct comparisons can be made.
Food and drug allergies are new categories added to the list of conditions in the 2011-12 survey.
Kidney disease was collected in a specific module for the first time in the 2011-12 survey.
This page last updated 4 April 2013
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