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Glossary

This glossary contains terms common to cardiovascular disease, diabetes and chronic kidney disease.

Aboriginal or Torres Strait Islander
A person of Aboriginal or Torres Strait Islander descent who identifies as an Aboriginal or Torres Strait Islander.

Additional diagnosis
A condition or complaint that either coexists with the principal diagnosis or arises during the hospitalisation. An additional diagnosis is reported if the condition affects patient management.

Age-standardisation
A method of removing the influence of age when comparing populations with different age structures. This is usually necessary because the rates of many diseases vary strongly (usually increasing) with age. The age structures of the different populations are converted to the same ‘standard’ structure, and then the disease rates that would have occurred with that structure are calculated and compared.

Associated cause(s) of death
All causes listed on the death certificate other than the underlying cause of death. They include the immediate cause, any intervening causes and conditions that contributed to the death but were not related to the disease or condition causing the death. See also cause of death.

Biomedical data
Biomedical or measured data―in the form of markers found during blood and urine testing―is the most accurate way to measure the prevalence of chronic diseases such as diabetes and chronic kidney disease. In the 2011–12 Australian Bureau of Statistics Australian Health Survey:

  • to detect biomedical signs of diabetes two tests were undertaken: a measure of fasting plasma glucose (FPG) and a measure of glycated haemoglobin (HbA1c).
  • to identify signs of chronic kidney disease two tests were undertaken to determine kidney function (estimated glomerular filtration rate (eGFR) and kidney damage (albumin creatinine ratio (ACR)).

Cause of death
The causes of death entered on the Medical Certificate of Cause of Death are all diseases, morbid conditions or injuries that either resulted in or contributed to death, and the circumstances of the accident or violence that produced any such injuries. Causes of death are commonly reported by the underlying cause of death. See also associated cause(s) of death.

Confidence interval (CI)
A statistical term describing a range (interval) of values within which we can be 'confident' that the true value lies, usually because it has a 95% or higher chance of doing so.

Hospitalisation
Refers to an episode of care for an admitted patient, which can be a total hospital stay (from admission to discharge, transfer or death) or a portion of a hospital stay beginning or ending in a change of type of care (for example, from acute care to rehabilitation). The same person may have multiple hospitalisations and it is currently not possible to link records of multiple hospitalisations in the AIHW National Hospital Morbidity Database to individuals and therefore to count the number of individuals being hospitalised, and their patterns of hospitalisations. There are 2 distinct types of diagnoses recorded in the database, principal diagnosis and additional diagnosis.

Incidence
Refers to the number of new cases of an illness, disease, or event occurring during a given period.

Other Australians
Includes people who did not identify as being of Aboriginal and/or Torres Strait Islander origin, and people for whom information on their Indigenous status was not available.

Prevalence
Is the number or proportion of cases or instances of a disease or illness present in a population at a given time. The prevalence of disease is related to both the incidence of the disease and how long people live after developing it (survival).

Principal diagnosis
The diagnosis established after study to be chiefly responsible for occasioning the patients hospitalisation.

Procedure
A clinical intervention that is surgical in nature, carries a procedural risk, carries an anaesthetic risk, requires specialised training and/or requires special facilities or equipment available only in an acute-care setting.

Self-reported
Self-reported data rely on survey participants being aware of, and accurately reporting, their health status and health conditions, which is not as accurate as data based on clinical records or measured data. As some people may not be aware that they have the condition estimates based on self-reported data, especially for conditions such as diabetes and chronic kidney disease, may underestimate the prevalence of these diseases. People also underestimate their weight yet overestimate their height, which are used to calculate body mass index for the assessment of overweight and obesity. Measured data are, therefore, more reliable in such instances.

Socioeconomic groups
Is an indication of how 'well off' a person or group is. Socioeconomic groups are reported using the Australian Bureau of Statistics’ Socio-Economic Indexes for Areas (SEIFA), whereby areas are classified on the basis of social and economic information (such as low income, low educational attainment, high levels of public sector housing, high unemployment and jobs in relatively unskilled occupations) collected in the Census of Population and Housing. Socio-Economic Indexes for Areas, are divided into 5 groups, from the most disadvantaged (worst off) to the least disadvantaged (best off). Note, that this index refers to the average disadvantage of all people living in an area, not to the level of disadvantage of a specific individual.

Remoteness
A system which classifies geographical locations into groups (Major cities, Inner regional, Outer regional, Remote, Very remote) according to distance from major population centres and services. In these analysis, remoteness is based on Accessibility/Remoteness Index of Australia (ARIA) and defined as Remoteness Areas by the Australian Statistical Geographical Standard (ASGS) (in each Census year). Remoteness is a geographical concept and does not take account of accessibility which is influenced by factors such as the socioeconomic status or mobility of a population.

Underlying cause of death
The disease or injury that initiated the sequence of events leading directly to death; that is the primary or main cause. For each death, only a single underlying cause is selected from among all the conditions reported on a death certificate.

Data sources

Australian Aboriginal and Torres Strait Islander Health Survey (AATSIHS)

The Australian Bureau of Statistics (ABS) 2012–13 Australian Aboriginal and Torres Strait Islander Health Survey (AATSIHS), which forms part of the broader 2011–13 Australian Health Survey, collected information from an additional sample of around 12,900 people from 8,300 households. The AATSIHS includes the National Aboriginal and Torres Strait Islander Health Survey (NATSIHS), the National Aboriginal and Torres Strait Islander Nutrition and Physical Activity Survey (NATSINPAS) and the National Aboriginal and Torres Strait Islander Health Measures Survey (NATSIHMS).

All Aboriginal and Torres Strait Islander people selected in the AATSIHS responded to either the NATSIHS or the NATSINPAS. However, there was a core set of data items common to both surveys; therefore, information for these data items is available for all persons in the AATSIHS (approximately 12,900 persons). This core set of data items included household information, demographics, self-assessed health status and self-assessed body mass. All Aboriginal and Torres Strait Islander people aged 18 and over were then invited to participate in the voluntary NATSIHMS.

Further information: Australian Aboriginal and Torres Strait Islander Health Survey: Users' Guide, 2012–13 (ABS cat. no. 4727.0.55.002)

Australian Health Survey

The Australian Bureau of Statistics 2011–12 Australian Health Survey (AHS) combines the existing National Health Survey (NHS) with two new components: a National Nutrition and Physical Activity Survey (NNPAS) and a National Health Measures survey (NHMS).

All people selected in the AHS were selected in either the NHS or the NNPAS. However, there was a core set of data items common to both surveys; therefore, information for these data items is available for all persons in the AHS (approximately 32,000). This core set of data items included household information, demographics, self-assessed health status and conditions. All people aged 5 and over were then invited to participate in the voluntary NHMS.

The AHS collected self-reported data on whether a respondent had 1 or more long-term health conditions; that is conditions that had lasted, or were expected to last, 6 months or more. The NHMS contained various tests aimed at detecting biomedical signs of diseases such as diabetes and chronic kidney disease.

Further information: Australia’s Health Survey: Users’ Guide, 2011–13 (ABS cat. no. 4363.0.55.001).

Australia and New Zealand Dialysis and Transplant Registry (ANZDATA)

ANZDATA collects information to monitor dialysis and transplant treatments from all renal units in Australia and New Zealand on all patients receiving kidney replacement therapy where the intention to treat is long term. Cases of acute kidney failure are excluded. The Registry is coordinated within the Queen Elizabeth Hospital in Adelaide, and compiles data on incidence and prevalence of treated end-stage kidney disease (ESKD), complications, comorbidities and patient deaths. All relevant hospitals and related dialysis units participate. While patients have the option of opting out of having part or all of their data recorded, this rarely happens.

The interpretation and reporting of the data in these web pages are the responsibility of the AIHW and in no way should be seen as an official policy or interpretation of the ANZDATA Registry.

Further information: ANZDATA Registry website.

National Health Survey

The Australian Bureau of Statistics (ABS) 2014–15 National Health Survey (NHS) was conducted to obtain national information on the health status of Australians, their use of health services and facilities, and health-related aspects of their lifestyle. The NHS collected self-reported data on whether a respondent had 1 or more long-term health conditions; that is, conditions that lasted, or were expected to last, 6 months or more.

When interpreting data from the 2014–15 NHS, some limitations need to be considered:

i) Much of the data is self-reported and therefore relies heavily on respondents knowing and providing accurate information.
ii) The survey is community-based and does not include information from people living in nursing homes or otherwise institutionalised.
iii) Residents of Very remote areas and discrete Aboriginal and Torres Strait Islander communities were excluded from the survey. This is unlikely to affect national estimates, but will impact prevalence estimates by remoteness.

The cross-sectional nature of the survey and exclusions should also be taken into account.

Also, some questions were asked of people aged 15 and over, others of adults aged 18 years and over. For example, information on:

  1. self-assessed health status was obtained for persons aged 15 and over
  2. psychological distress and bodily pain were obtained for persons aged 18 and over.

Further information: National Health Survey: First results, 2014–15 (ABS cat. no. 4364.0.55.001).

National Hospital Morbidity Database

The AIHW National Hospital Morbidity Database (NHMD) is a compilation of episode-level records from admitted patient morbidity data collection systems in Australian hospitals. Reporting to the NHMD occurs at the end of a person’s admitted episode of care (separation or hospitalisation) and is based on the clinical documentation for that hospitalisation. The NHMD is based on the Admitted Patient Care National Minimum Data Set (APC NMDS). It records information on admitted patient care (hospitalisations) in essentially all hospitals in Australia, and includes demographic, administrative and length-of-stay data, as well as data on the diagnoses of the patients, the procedures they underwent in hospital and external causes of injury and poisoning.

The hospital separations data do not include episodes of non-admitted patient care given in outpatient clinics or emergency departments. Patients in these settings may be admitted subsequently, with the care provided to them as admitted patients being included in the NHMD. The following care types were excluded when undertaking the analysis: 7.3 (newborn—unqualified days only), 9 (organ procurement—posthumous) and 10 (hospital boarder).

Further information: Data quality statement: National Hospital Morbidity Database 2014–15.

The National (insulin-treated) Diabetes Register

The National (insulin-treated) Diabetes Register (NDR) holds information about people who use insulin as part of their treatment for diabetes. The NDR was established in 1999 and includes most people diagnosed with type 1 diabetes since this time, as well as those who use insulin to manage type 2 diabetes, gestational diabetes and other, less common forms of diabetes.

Almost all people with type 1 diabetes who were diagnosed from 1999 onwards are captured on the NDR. This is because all people with type 1 diabetes require insulin to treat their condition and this need for insulin acts as a driver to register with the National Diabetes Services Scheme where the products for administering insulin (pens/needles, or insulin pump consumables) can be obtained at subsidised prices. Additionally, the coverage rate of the National (insulin-treated) Diabetes Register is high for those diagnosed under 15 years as data are also obtained from the Australasian Paediatric Endocrine Group state-based registers.

Further information: The National (insulin-treated) Diabetes Register 2014; Data Quality Statement.

National Mortality Database

The mortality data used in this report were provided by the Registries of Births, Deaths and Marriages, the Coroners and the National Coroners Information System and coded by the Australian Bureau of Statistics (ABS). These data are maintained at the Australian Institute of Health and Welfare (AIHW) in the National Mortality Database. Registration of deaths is the responsibility of the state and territory Registrars of Births, Deaths and Marriages.

Analysis is by year of registration. Deaths registered in 2010 that occurred before 2007 for usual residents of Queensland were excluded from the 2010 year of registration data as recommended by the ABS. This is to minimise the impact of late registration of deaths due to recent changes in the timeliness of death registrations in Queensland.

Deaths registered in 2012 and earlier are based on the final version of cause of death data; deaths registered in 2013 and 2014 are based on revised and preliminary versions, respectively and are subject to further revision by the ABS.

The data quality statements underpinning the AIHW National Mortality Database can be found in the following Australian Bureau of Statistics (ABS) publications:

Reporting deaths by Aboriginal and Torres Strait Islander status is done for 5 jurisdictions with adequate identification of Indigenous status. Analysis of deaths data by Indigenous status between 2009 and 2011 are based on data where the deceased’s state of residence was New South Wales, Queensland, Western Australia, South Australia or the Northern Territory.

National Perinatal Data Collection

The AIHW National Perinatal Data Collection (NPDC) is a data collection of pregnancy and childbirth, based on forms completed by midwives and other staff in each state and territory in Australia. The National Perinatal Epidemiology and Statistics Unit (NPESU), a collaborating unit of the Australian Institute of Health and Welfare based at the University of New South Wales, compiles selected information into a national dataset each year. The dataset includes data items relating to the mother, including demographic characteristics and factors relating to the pregnancy, labour and birth, and data items relating to the baby, including birth status, sex and birthweight.

Further information: National Perinatal Data Collection, 2012: Data Quality Statement.

Survey of Disability, Ageing and Carers (SDAC)

These surveys were conducted by the ABS to collect information about the following: people of all ages with a disability, older people (aged 60 and over), and people who provide assistance to older people and people with disabilities. The surveys included people in both private and non-private dwellings (including people in establishments where care is provided) but excluded those in correctional institutions.

The ABS Survey of Disability, Ageing and Carers (SDAC) provides more reliable estimates on the prevalence of stroke than the ABS 2011–12 Australian Health Survey. This is because the SDAC includes more comprehensive questions on long-term conditions and associated activity limitations, and includes non-private dwellings, such as residential aged care facilities. This is particularly important when reporting on stroke because stroke is strongly associated with increasing age, and many survivors of stroke require the special care that these facilities provide.

Further information: ABS Disability, Ageing and Carers, Australia: Summary of Findings, 2012 (ABS cat. no. 4430.0).