4363.0 - National Health Survey: Users' Guide, 2017-18  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 30/04/2019   
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Health conditions

The 2017-18 NHS collected data on a broad range of health conditions a person may have, with the primary focus on current and long-term conditions. Some conditions have been selected to be of greater importance in policy planning and are specifically asked in individual modules to ensure high quality detailed results for these conditions. For collection methodology and interpretation specific to each condition, the appropriate topic section should be reviewed.

The individual condition modules are:

    • Asthma
    • Arthritis
    • Cancer
    • Cardiovascular disease
    • Diabetes and high sugar levels
    • Kidney disease
    • Osteoporosis
    • Mental, behavioural and cognitive conditions.

The NHS also collected information on sight and hearing and other long-term conditions.

In the specific conditions modules, respondents are asked whether they have been diagnosed. Respondents are also asked whether the condition is current and long-term, except where an assumption is made (e.g. cancers are considered to be long-term if they are identified as current). This is discussed in more detail in the individual sections on these conditions. Each reported condition was then classified into the following condition status output categories:
    1. Ever told has condition, still current and long-term
    2. Ever told has condition, still current but not long-term
    3. Ever told has condition, not current.

Respondents without a condition are classified into category 5: Never told, not current or long-term. An additional category '4: Not known or not ever told, but condition current and long-term' is also used where respondents are not asked about diagnosis.

Condition prevalence is usually reported based on categories 1 and 4 (where applicable in NHS), i.e. that the condition is current and long-term. Diabetes and, some heart stroke and vascular conditions were reported as long term and current, regardless of the condition status reported at interview. Current long-term conditions are defined as medical conditions (illnesses, injuries or disabilities) which were current at the time of the survey and which had lasted at least six months, or which the respondent expected to last for six months or more, including:
    • Long-term conditions from which only infrequent attacks may occur
    • Long-term conditions which may be under control, for example, through the continuing use of medication
    • Conditions which, although present, may not be generally considered ‘illness’ because they are not necessarily debilitating, e.g. reduced sight
    • Long-term or permanent impairments or disabilities.

In addition to the above conditions, the NHS collected information on self-assessed health, disabilities and bodily pain.

Population

Information was obtained for all persons.

Classification of conditions

Conditions reported by respondents were coded 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. The detailed output classification used for NHS was developed by the ABS based on mapping between the 1000 input code list and 10th Revision of the International Classification of Diseases (ICD10) provided by the Family Medicine Research Centre. The classification takes into account:
    • The types of long-term conditions more commonly reported in a population based survey and for which reliable estimates could be produced
    • The types of conditions or groups of conditions known to be of particular interest to data users
    • The variability of the descriptions of conditions provided by respondents.

While information from the ICD10 was used in the development of this list, results 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.

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 Computer Assisted Interview (CAI) instruments. Predefined response categories in the questionnaires were allocated unique codes within the 1000 input code list.

For the majority of conditions, interviewers were able to select the appropriate condition from either category responses for questions or from a trigram coder attached to ‘other’ response categories. Where the interviewer could not find the condition in the coder or the condition name was not known at the time of the interview, 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. Copies of the standard classifications of medical conditions available from the NHS are contained in Appendix 2: Classification of medical conditions available in the Downloads page of this product.

Number of conditions

There are four data items available from the 2017-18 NHS relating to the number of conditions reported. They are:
    • Number of conditions reported (includes any condition reported regardless of condition status)
    • Number of current conditions reported (includes only conditions reported as current - the condition may or may not be long-term)
    • Number of current long-term conditions reported (includes only conditions reported as current and long-term).
    • Number of selected chronic conditions groups (see definition in the comorbidity chapter for information about the inclusion of conditions by condition status).

Chronic conditions

Chronic conditions are conditions that contribute to premature mortality and morbidity. Persons diagnosed with one or more types of chronic conditions often have complex health needs, have poorer quality of life and die prematurely.

In the First Release publication, 'selected chronic conditions' consist of the following:
    • Arthritis
    • Asthma
    • Back problems
    • Cancer
    • Chronic obstructive pulmonary disease (COPD)
    • Diabetes mellitus
    • Heart, stroke and vascular disease
    • Kidney disease
    • Mental and behavioural conditions
    • Osteoporosis.

Number of selected chronic condition groups

The number of selected chronic conditions data item counts the number of chronic condition groups an individual has at least one condition within. For individuals who may have multiple conditions that belong to the same condition type (e.g. Mental and behavioural conditions), these conditions are only counted once, For example, a person with Anxiety and Depression (and no other chronic condition) is counted once within the Mental and Behavioural conditions group.

Methodology

This data item combines information from two separate data items: Type of condition ICD10 and Condition Status. These combined items are then given a weight to create a count of the number of chronic conditions groups that an individual has at least one condition in. The table below describes the combination of the conditions used in this data item as well as the status of the conditions reported. Results using this data item are presented Table 1, 18 and 19 of National Health Survey: First Results 2017-18 (cat. no. 4364.0.55.001)

Specifications of the number of chronic conditions group data item

Condition groupCondition status
Arthritis includes:
  • rheumatoid arthritis
  • osteoarthritis
  • other arthritis
  • type unknown
  • 1. Ever told has condition, still current and long-term
  • 4. Not known or not ever told, but condition current and long-term
Blank
Asthma
  • 1. Ever told has condition, still current and long-term
  • 4. Not known or not ever told, but condition current and long-term
Blank
Back Pain (Dorsopathies) includes:
  • sciatica
  • disc disorders
  • back pain/problems nec.
  • curvature of the spine
  • 1. Ever told has condition, still current and long-term
  • 4. Not known or not ever told, but condition current and long-term
Blank row
Cancer (Malignant neoplasms)
  • 1. Ever told has condition, still current and long-term
  • 4. Not known or not ever told, but condition current and long-term
Blank
Chronic Obstructive Pulmonary Disease (COPD) includes:
  • Bronchitis
  • Emphysema
  • 1. Ever told has condition, still current and long-term
  • 4. Not known or not ever told, but condition current and long-term
Blank
Diabetes (excluding gestational diabetes) includes all instances of :
  • Type 1 diabetes
  • Type 2 diabetes
  • Type unknown
  • 1. Ever told has condition, still current and long-term
  • 2. Ever told has condition, still current but not long-term
  • 3. Ever told has condition, not current
  • 4. Not known or not ever told, but condition current and long-term
Blank
Heart, stroke and vascular disease includes all instances of:
  • angina
  • heart attack
  • other ischaemic heart diseases
  • heart failure
  • stroke
  • other cerebrovascular disease
  • 1. Ever told has condition, still current and long-term
  • 2. Ever told has condition, still current but not long-term
  • 3. Ever told has condition, not current
  • 4. Not known or not ever told, but condition current and long-term
Blank
Heart, stroke and vascular disease also includes current and long-term instances of:
  • oedema
  • disease of arteries, arterioles and capillaries
  • 1. Ever told has condition, still current and long-term
  • 4. Not known or not ever told, but condition current and long-term
Blank
Kidney disease
  • 1. Ever told has condition, still current and long-term
  • 4. Not known or not ever told, but condition current and long-term
Blank
Mental and Behavioural conditions includes:
  • alcohol and drug problems
  • mood (affective disorders)
  • anxiety related disorders
  • other mental and behavioural conditions
  • 1. Ever told has condition, still current and long-term
  • 4. Not known or not ever told, but condition current and long-term
Blank
Osteoporosis
  • 1. Ever told has condition, still current and long-term
  • 4. Not known or not ever told, but condition current and long-term


Number of selected chronic condition groups comparability with 2014-15

The definition of number of chronic conditions was changed between 2014-15 NHS and 2017-18 NHS and are not comparable. In 2017-18, the definition was expanded to include kidney disease and osteoporosis, while the inclusion of cardiovascular disease previously included in 2014-15 NHS was reduced to selected heart, stroke and vascular diseases. In addition to the definition change, the title of the data item has changed from 'Number of chronic diseases' to 'Number of selected chronic condition groups'.

Time series data presented in Table 1 of the National Health Survey: First Results 2017-18 (cat. no. 4364.0.55.001) use the 2017-18 definition.

Points to consider
    • It is expected that conditions which were specifically mentioned in questions or (to a lesser extent) shown on prompt cards would have been better reported than conditions for which responses relied entirely on respondent judgement and willingness to report them. Data are not available from this survey to enable the magnitude of this effect to be quantified, but it is likely to differ across condition types and for different groups in the population.
    • Although in the 2017-18 NHS long-term/permanent disabilities were within the scope of general conditions data, data output from the ICD-10 should not be interpreted as indicating the population with disability. In some cases, long-term/permanent impairment/disability could be evident from the condition categories, e.g. blindness (complete or partial), while for others some degree of impairment/disability could be inferred from the nature of the condition, e.g. back problems. However, these data should, at best, be considered as proxy indicators of disability only. See Disability subsection, for more information.
    • The prevalence of most long-term illness increases with age. In drawing comparisons of prevalence between NHS 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 National Health Survey: First Results, 2017-18 (cat. no. 4364.0.55.001) has been age standardised so that direct comparisons can be made.

More information regarding comparisons between 2014-15 NHS and previous cycles is available in the National Health Survey: Users' Guide, 2014-15 (cat. no. 4363.0).

This section contains the following subsections:
    • Self-assessed health
    • Asthma
    • Arthritis
    • Cancer
    • Cardiovascular disease
    • Diabetes and high sugar levels
    • Kidney disease
    • Osteoporosis
    • Sight and hearing
    • Other long-term conditions
    • Disability
    • Bodily pain
    • Mental health and wellbeing
    • Kessler Psychological Distress Scale - 10 (K10)
    • Mental, behavioural and cognitive conditions
    • Comorbidity