age-standardisation: A set of techniques used to remove, as far as possible, the effects of differences in the age structure when comparing 2 or more populations.

age-standardised rate (ASR): A rate that takes into account the age structure of the population using age-standardisation techniques.

associated cause(s) of death: A cause(s) listed on the Medical Certificate of Cause of Death other than the underlying cause of death. Causes include the immediate cause, any intervening causes and conditions that contributed to the death but were not related to the disease or condition causing death. See also cause(s) of death.

burden of disease (and injury): The quantified impact of a disease or injury on a population using the disability-adjusted life years (DALY) measure.

cause(s) of death: 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—that are entered on the Medical Certificate of Cause of Death. Causes of death are commonly reported by the underlying cause of death. See also associated cause(s) of death and underlying cause of death.

chronic: Persistent and long-lasting.

comorbidity: A health problem/disease that exists at the same time as (an)other health problem(s).

conceptual disease model: A representation of clinical conditions designed to summarise what is known about the disease epidemiology, the nature of the disease (that is, whether it is chronic, acute, episodic or progressive), and its treatment.

condition (health condition): A broad term that can be applied to any health problem, including symptoms, diseases and certain risk factors, such as high blood cholesterol and obesity. Often used synonymously with disorder or problem.

COVID-19 (Coronavirus disease 2019): An infectious disease caused by the SARS-CoV-2 virus.

COVID-19 death: A death directly due to the SARS-CoV-2 virus. Also referred to as deaths due to COVID-19.

COVID-19 related death: A death where there is a disease or injury pathway to death that is not directly caused by the SARS-CoV-2 virus. Also referred to as deaths with COVID-19. For example, a person may have late stage cancer that has metastasised causing organ damage leading to death. This person may also have contracted COVID-19. While the virus may have negatively impacted health in an immuno-compromised person, the virus itself did not cause the terminal event leading to death (e.g. organ failure). In this example, the underlying cause of death would be cancer and COVID-19 would be considered an associated cause of death (ABS 2022a).

crude rate: A burden (YLD, YLL or DALY) rate derived from the number of years of healthy life lost recorded in a population during a specified time period divided by the number of people in the population, without adjustments for other factors such as age (see age-standardisation).

disability: In burden of disease analysis, any departure from an ideal health state.

disability-adjusted life years (DALY): A year of healthy life lost, either through premature death or living with disability due to illness or injury.

disability weight: A factor that reflects the severity of health loss from a particular health state on a scale from 0 (perfect health) to 1 (equivalent to death).

disease: A broad term that can be applied to any health problem, including symptoms, diseases, injuries and certain risk factors, such as high blood cholesterol and obesity. Often used synonymously with condition, disorder or problem.

external cause: The environmental event, circumstance or condition that causes injury, poisoning and other adverse effects (e.g. road traffic accident).

fatal burden: The burden from dying prematurely as measured by years of life lost (YLL). Often used synonymously with years of life lost, and also referred to as ‘life lost’.

health-adjusted life expectancy (HALE): The average number of years that a person at a specific age can expect to live in full health; that is, taking into account years lived in less than full health due to the health consequences of disease and/or injury.

health state: Reflects a combination of signs and symptoms that result in health loss, and are not necessarily unique to one particular disease. A health state might also be a severity level of a sequela (typically mild, moderate and severe levels are distinguished). For example, the health state ‘mild heart failure’ is used as a sequela of coronary heart disease, hypertensive heart disease, congenital heart disease and several other conditions. Each health state is associated with a disability weight.

hospitalisation: An episode of hospital care that starts with the formal admission process and ends with the formal separation process (synonymous with separation).

incidence: Refers to the occurrence of a disease or event. The incidence rate is the number of new cases occurring during a specified time period.

International Classification of Diseases (ICD): The World Health Organization’s internationally accepted classification of diseases and related health conditions. Mortality data sourced from the AIHW’s National Mortality Database (NMD) are coded using the ICD-10, 10th revision. The 10th revision, Australian modification (ICD-10-AM) is currently in use in Australian hospitals for admitted patients.

morbidity: Ill health in an individual, and levels of ill health in a population or group.

mortality: Death.

non-fatal burden: The burden from living with ill health as measured by years lived with disability (YLD). Often used synonymously with years lived with disability, and also referred to as ‘health loss’.

post COVID-19 condition: A condition that occurs in individuals with a history of probable or confirmed SARS CoV-2 infection, usually 3 months from the onset of COVID-19 with symptoms that last for at least 2 months and cannot be explained by an alternative diagnosis. Common symptoms include fatigue, shortness of breath, cognitive dysfunction and others, and generally have an impact on everyday functioning. Symptoms may be new onset following initial recovery from an acute COVID-19 episode or persist from the initial illness. Symptoms may also fluctuate or relapse over time. Also referred to as ‘long COVID’ or ‘post-acute consequences of COVID-19’.

premature death: Deaths that occur at a younger age than a selected cut-off. In the ABDS, it is defined as dying before the global ideal life span at the age of death.  

prevalence: Refers to the existence of a disease or event in a population, whether or not it is newly occurring; the prevalence rate is the number of cases existing at a point in time (point prevalence) or over a specified time period (period prevalence) divided by the number of people in the population.

rate: A burden (YLD, YLL or DALY) rate is one number (the numerator) divided by another number (the denominator). The numerator is commonly the number of years of healthy life lost in a specified time. The denominator is the population at risk of the event. Rates (crude, age-specific and age-standardised) are generally multiplied by a number such as 1,000 to create whole numbers.

redistribution: A method in a burden of disease study for reassigning deaths with an underlying cause of death that is not in the study’s disease list. Typically, the deaths reassigned include: those with a case that is implausible as an underlying cause of death; those that relate to an intermediate cause in the chain of events leading to death; or those for which there is insufficient detail to ascertain a specific cause of death.

reference life table: A table that shows, for each age, the number of remaining years a person could potentially live. Used to measure the years of life lost from dying at each age.

sequelae: Health consequences of diseases and injuries, such as heart failure due to coronary heart disease. Each sequela may be mapped to one or more health states.

total burden: The sum of fatal burden (YLL) and non-fatal burden (YLD), which totals disability-adjusted life years (DALY). See burden of disease (and injury).

underlying cause of death: The primary or main cause of death: the condition, disease or injury that initiated the sequence of events leading directly to death, or the circumstances of the accident or violence that produced the fatal injury. See also cause(s) of death and associated cause(s) of death.

years lived with disability (YLD): Measures the years of what could have been a healthy life that were instead spent in states of less than full health. YLD represent non-fatal burden.

years of life lost (YLL): Measures years of life lost due to premature death, defined as dying before the global ideal life span at the age of death. YLL represent fatal burden.