Methods and data sources

Expenditure estimates presented in this report are sourced from the AIHW disease expenditure database. The disease expenditure database contains estimates of expenditure by Australian Burden of Disease Study (ABDS) condition, age group, and sex, for public and private admitted patient, emergency department, and outpatient hospital services, out-of-hospital medical services, and prescription pharmaceuticals (AIHW 2021b). A range of modelling techniques and data sources are used to apportion health spending to population groups. Due to data availability, allocated spending is skewed towards activity in hospitals, and estimates should be interpreted with this in mind.

This report uses additional data sources to allocate to sport and physical activity injury spending captured within the disease expenditure database. This analysis is part of a larger body of work to characterise the economic impact of sport and physical activity, and a broad classification of activities is used to maintain consistency between injury estimates and the ABDS physical inactivity risk factor.

The ABDS risk factor ‘physical inactivity’ largely adheres to the scope from the Australian physical activity guidelines to estimate activity levels in terms of activities counted as physical activity (all physical activity domains, such as leisure, transport, occupational and household chores). This is to ensure that an accurate measure of total physical activity levels undertaken in Australia are included.

The cost of injuries presented in this report reflect injuries from all types of physical activity, not only ‘sport related’ injuries.

Measuring the hospital costs of physical activity related injury

Hospitalisations for injury are classified using the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian modification (ICD-10-AM) Principal Diagnosis codes S00–T75 or T79. These codes are supplemented with an ICD-10-AM ‘Activity at the time of injury’ code in the range U50–U71, which allows the grouping of hospitalisations into physical activity and non-physical activity related. The cost of injuries presented in this report reflect injuries from all types of physical activity, not only ‘sport related’ injuries. The classification of ICD codes into ‘physical activity related’ is broad, so as to capture the spectrum of activities that are considered physical activity in the specifications for the physical inactivity risk factor, and includes codes such as ‘leisure activity not elsewhere classified’.

Unlike admitted patient data, emergency department diagnosis data does not contain an ‘Activity at the time of injury’ code. The proportion of injuries due to physical activity has been estimated using the attribution of each ICD-10-AM diagnosis code to activities in the admitted patient data, applied to ICD-10-AM diagnoses in emergency departments. This method potentially underestimates injury spending from physical activity, if there are differences in injury severity (and likelihood of hospital admission) based on how an injury was sustained.

Measuring the non-hospital and outpatient costs of physical activity related injury

Not all injuries are treated in an emergency department or during a hospital admission. General practitioners, physiotherapists, and sports medicine physicians are common locations where treatment of lower severity injuries may occur. Data relating to the activities undertaken when injuries occurred is not available in these non-hospital settings and is estimated from published studies.

Data from a general practice injury surveillance study was used to allocate injuries by type to sport/physical activity (Day 1998, Cassell 2003). The injury types reported in this study were grouped into fractures, soft tissue injuries, and all other injuries. As dislocations were not specified by the authors, the sport/physical activity proportion for dislocations was estimated as the average of fractures and soft tissue injuries. Costs of hip fractures were allocated to physical activity using the proportion of ‘all other injuries’, as the nature of these injuries often varies from that of other fractures.

Allocation of injury costs in hospitals to specific activities

Injury costs and average cost per participant are presented for the most popular sports. Selected sports are discussed in more detail, including the various football codes, wheeled motor sports, netball, and cricket. These estimates are only available for public and private admitted patients due to data availability.

The activities at time of injury recorded during an episode of admitted patient care are mapped from the ICD code to an activity group. The reporting categories are chosen for their consistency with Sports injury hospitalisations in Australia, 2019-20 and the available participation data. Refer to the Technical notes for further information.

Participation rate data are drawn from the Clearinghouse for Sport's AusPlay survey. Every year, the AusPlay survey asks a sample of 20,000 Australians about their participation in sports and physical recreation. The survey results include estimates of the number of participants in a range of activities. This report only includes estimates of participants aged 15 and over.