Coding the circumstances of injury: ICD-10 a step forward or backwards?

The International Classification of Diseases (ICD) E codes are the most widely used coding frame for categorising the circumstances of injury and poisoning. In 1992 major revisions to the E codes were released. The aim of this paper was to consider whether the changes made are a step forward or backwards in terms of facilitating injury prevention. The approach taken was to reflect on some former injury prevention research needs and the challenges they presented using data coded according to ICD-9, and then to consider how, if at all, ICD-10 has addressed these difficulties. As with ICD-9, there are essentially two axes associated with each cause: intent and mechanism of injury, and these are captured by one code. This approach can have the unintended effect of hiding the significance of some mechanisms of injury. While there have been significant improvements in some areas, such as falls, in others, such as injuries due to firearms, ICD-10 has taken a step backward. In addition the failure to produce mutually exclusive codes presents problems for determining the incidence of downing events. A welcome addition are "optional" activity codes which enable the identification of work related and sport related injury for the first time. Nevertheless, the limited range of codes and absence of coding guides limits their utility. The revised place of occurrence codes do not represent a significant improvement on ICD-9 in that they are limited to 10, they are not mutually exclusive, and they do not adequately cover a range of specific places of occurrence. In summary, relative to its predecessor, ICD-10 represents a significant improvement in many areas. Unfortunately, it still falls far short of the mark for many injury prevention needs.