To the Editor: Quality data about patients with injuries requiring hospitalisation is vital to injury policy and prevention strategies.1 The ICD-10-AM is used in Australia to assign codes to diagnoses, procedures, and causes of injury recorded in patient medical records.2 This coded hospital morbidity data provides a key surveillance tool for injury researchers.

ICD classifications are designed for statistical reporting and are required for classifying all information encountered in hospital medical records. When insufficient information is available in the medical record to assign specific codes, the use of residual “Unspecified” categories helps to achieve this.

Detailed and accurate documentation provided by clinicians in patient medical records is imperative to produce high quality coded data.3 Poor documentation in medical records has been shown to decrease data quality by contributing to an overuse of “Unspecified” codes.4 This is especially so for documenting external cause of injury, which may not be seen as critical to the patient’s care by the treating clinician, with the result that the relevant detail is incomplete or omitted altogether.

We aimed to identify the level of precision of coded injury data in Australian hospitals. Using the 2003–2004 national morbidity dataset, 445 098 records containing an injury and an external cause classified by intent were found (Box). At a broad intent level, the majority of injuries were assigned to a specific mechanism code, although in two intent categories, “Accident” and “Assault”, 11% and 13% of injuries, respectively, were assigned to “Unspecified” categories. It is concerning that 45 297 of the injuries requiring hospitalisation lacked adequate documentation in the medical record to permit meaningful code assignment for cause of injury.

A significant lack of precision was evident in recording mechanisms of accidental falls and poisonings (across all intents). A quarter of falls and 20% of poisoning cases had no specific information about the causal mechanism or substance. Being the most commonly reported accident mechanism, falls of unspecified cause represented 11% of accidents overall. This lack of detail is particularly concerning given the significant national priority now placed on falls and poisoning injury prevention.5

It is essential that clinicians and coders alike are aware of documentation and coding problems related to capturing data on cause of injury. By working together to improve the quality of injury-related coded data (through improved clinical documentation), accurate and comprehensive information pertaining to the circumstances surrounding injury events requiring hospitalisation will benefit injury policy and prevention initiatives.