Answering these questions requires the right data

The likelihood of subsequent injury can be influenced by previous injury occurrences.1 It is therefore crucial that all available sports injury surveillance data is used in reporting injuries.3 Shrier et al 2 state: ‘Maximising this potential requires that data be entered in a format that can be interpreted and analysed’. Finch and Marshall3 illustrated graphically why it is so important to use all data on index and subsequent injuries, as well as the information on elapsed time, to better understand the epidemiology of subsequent injury. Moreover, in the context of better reporting of multiple injuries within individuals, ‘Online and automated forms of data collection will be further enhanced … if … reporting algorithms that make the most of individual-level data also become widely used’.4

So what is the right data?

Table 1 shows the data required about both the individual and their injury/ies. In order to capitalise on longitudinal data, that is, to track athletes over time, each person needs to be individually identifiable throughout the study period. For this, a unique identifier is necessary. In terms of the injury data, correctly specifying the timing of injury occurrences is crucial; data must reflect specifically when the injury occurred and when the injury recovered. While an objective definition of recovery is subject to ongoing debate, return to play is generally accepted as a reasonable proxy.4 5

One particular challenge is to distinguish between multiple injuries that occur across different events (perhaps a muscle strain at the start of a match and a head injury later in the game) and also where multiple injuries occur at the same time (e.g. in the same tackle incident, a player sustains the muscle strain and head injury together). This is another reason why a record of the timing of injuries is so critical.

Setting new data reporting standards

Current differences in the wording of, and definitions used for, injury, recovery, recurrent, subsequent and so on can be confusing, particularly for sports medicine professionals working outside of epidemiology. The use of different definitions will lead to variations in the classification of injuries and, in turn, affect the accurate calculation of injury incidence. Definitions also affect correct understanding of risk factors and decision making around treatment options for athletes with multiple injuries. Table 1 provides guidance on how to improve this in relation to the timing of injury occurrences.

Returning athletes to their preinjury function, and preventing future injuries, is the major goal of treatment and rehabilitation. Better prediction of the incidence, causes of and potential for prevention of injury, reinjury and improved recovery needs robust high-quality data. This should be collected through high-quality injury data collection systems that contain all of the relevant information. It is hoped that this list of key data items needed for the reporting of subsequent injuries will contribute to new data collection and reporting standards for the prospective monitoring of injuries.

This paper contributes to injury surveillance standards by listing the key data items that need to be collected and reported on to fully understand multiple and subsequent injuries in athletes. These data items apply irrespective of the subsequent injury definition.1 2 6 Collecting the most appropriate injury data in a timely and robust way will ensure continual improvements to sports injury data collections to underpin inform clinical decision making, in turn improving the health and injury outcomes for all athletes.