Summary
Burden of disease analysis produces comparable and concise policy-relevant evidence on the impact of disease, injuries and risks on the population. A key strength of burden of disease is the ability to collate and use data from various sources to develop an internally consistent measure for all diseases. However, as methods used in burden of disease analyses have become increasingly complex over time, the increased complexity makes it much harder to explain the methods, and can result in decreased clarity for stakeholders.
This report describes, as far as practicable, the methods and assumptions used by the Australian Burden of Disease Study (ABDS) 2015 to quantify the fatal and non-fatal effects and causes of diseases and injuries in the Australian population in 2015, 2011 and 2003.
It is a companion publication to Australian Burden of Disease Study: impact and causes of illness and death in Australia 2015 (AIHW 2019a) and Australian Burden of Disease Study: impact and causes of illness and death in Australia 2015—summary report (AIHW 2019b) and was developed to provide transparency of data, assumptions and methods. This report supersedes the methods described in the Australian Burden of Disease Study 2011: Methods and supplementary material (AIHW 2016a) for the national component of the ABDS 2011.
The ABDS 2015 does not estimate the burden of disease and injuries on the Aboriginal and Torres Strait Islander populations as key data sources were not available at the time of analysis.
To make the report easier to read, large tables and additional information are presented in appendices A to G.
Key considerations
The ABDS 2015 methods build on the methodological approach of the ABDS 2011 (AIHW 2014a; AIHW 2016a), along with methodological developments used in recent iterations of the Global Burden of Disease study (GBD 2015 and 2016). Key considerations for the ABDS 2015 were the need for:
- national estimates which were relevant to Australia, while maintaining comparability with global methods as much as possible
- sub-national estimates (state/territory, remoteness and socioeconomic group)
- comparability to 2011 and 2003 estimates to enable valid comparisons over time.
In addition, the following principles were followed to enable improvements and extensions to the methods used in ABDS 2011 (Box 1.1).
Box 1.1: Principles for the ABDS 2015 update
- If changes were made to the ABDS disease list, methods or model inputs, estimates for previous time points were re-generated to enable true comparison over time.
- Changes to key inputs (such as disability weights or reference life table) or methods (such as redistribution or comorbidity bias adjustment) must not introduce bias or compromise the consistent and systematic approach for all diseases which is the foundation of the ABDS.
- Changes to models, model inputs or data sources must:
- be introduced to improve accuracy and/or defensibility and be evidence-based
- take into consideration the appropriateness of the change to previous time points.
For example, changes in duration of health loss must consider whether it is appropriate to apply that change to all time points, or only the most recent time point. Changes in duration for more recent time points reflect advances in treatment; ultimately reducing the time spent in ill-health.
- Variations to the list of diseases/injuries must:
- comply with criteria developed for selection of diseases and injuries in the ABDS (see Chapter 2)
- maintain the existing disease list structure
- maintain mutual exclusivity
- be consistent with diseases used in the risk factor component.
- Variations to the risk factors list must:
- comply with criteria developed for selection of risk factors in the ABDS
- be consistent with the disease list (including sequelae) in terms of the associated linked diseases.
1. Introduction
- Key considerations
- Expert advice and review
2. Overarching methods and choices
- Reference years 2015, 2011 and 2003
- Reference populations
- Age groups
- Selection and classification of diseases
- Methodological choices specific to sub-national estimates
- Methodological choices specific to 2003 and 2011 estimates
3. Estimating the fatal burden
- Overview of methods
- Mortality data
- Aligning causes of death to the ABDS disease list
- Reference life table
- Sub-national estimates
4. Estimating the non-fatal burden
- Overview of methods
- Conceptual disease models
- Disability weights
- Estimating point prevalence of each sequela
- Dealing with comorbidity
- Estimating YLD for residual diseases
5. Disease specific methods
- Blood and metabolic disorders
- Cancer and other neoplasms
- Cardiovascular diseases
- Endocrine disorders
- Gastrointestinal disorders
- Hearing and vision disorders
- Infant and congenital conditions
- Infectious diseases
- Injuries
- Kidney and urinary conditions
- Mental and substance use disorders
- Musculoskeletal conditions
- Neurological conditions
- Oral disorders
- Reproductive and maternal conditions
- Respiratory diseases
- Skin disorders
6. Estimating the health-adjusted life expectancy
- Method for estimating HALE
- Estimating morbidity
- Estimating mortality
- Calculating HALE
- Data sources
- Alignment of non-fatal burden and life table data
- Sub-national estimates
7. Overarching methods and choices for risk factors
- Methodological developments since the ABDS 2011
- Steps in estimating risk factor attributable burden
- Selection of risk factors
- Selection of linked diseases
- Theoretical minimum risk exposure distribution
- Population distribution of exposure
- Estimates of effect size (relative risks)
- Calculation of population attributable fractions
- Calculating the attributable burden
- Attributable burden estimates by socioeconomic group
- 2011 and 2003 estimates
- Changes in risk factor exposure over time
8. Risk factor specific methods
- Tobacco use
- Alcohol use
- Physical inactivity
- Illicit drug use
- Intimate partner violence
- Unsafe sex
- Child abuse and neglect
- Overweight and obesity
- High blood pressure
- High blood plasma glucose (including diabetes)
- High cholesterol
- Impaired kidney function
- Iron deficiency
- Low bone mineral density
- Occupational exposures and hazards
- High sun exposure
- Air pollution
- Dietary risk factors
9. ABDS quality framework
- Ensuring quality of inputs to the ABDS
- ABDS 2015 quality index
Appendix A: Additional information and tables for Chapter 2
Appendix B: Additional information and tables for Chapter 3
Appendix C: Additional information and tables for Chapter 4
Appendix D: Additional information and tables for Chapter 5
Appendix E: Additional information and tables for Chapter 6
Appendix F: Additional information and tables for Chapter 7
Appendix G: Additional information and tables for Chapter 9
Appendix H: List of expert advisors
End matter: Acknowledgments; Abbreviations; Symbols; Glossary; References; List of tables; List of figures