Children and youth with 'unspecified injury to the head': implications for traumatic brain injury research and surveillance

The case definition for traumatic brain injury (TBI) often includes 'unspecified injury to the head' diagnostic codes. However, research has shown that the inclusion of these codes leads to false positives. As such, it is important to determine the degree to which inclusion of these codes affect the overall numbers and profiles of the TBI population. The objective of this paper was to profile and compare the demographic and clinical characteristics, intention and mechanism of injury, and discharge disposition of hospitalized children and youth aged 19\ua0years and under using (1) an inclusive TBI case definition that included 'unspecified injury to the head' diagnostic codes, (2) a restricted TBI case definition that excluded 'unspecified injury to the head 'diagnostic codes, and (3) the 'unspecified injury to the head' only case definition.The National Ambulatory Care Reporting System and the Discharge Abstract Database from Ontario, Canada, were used to identify cases between fiscal years 2003/04 and 2009/10.The rate of TBI episodes of care using the inclusive case definition for TBI (2,667.2 per 100,000) was 1.65 times higher than that of the restricted case definition (1,613.3 per 100,000). 'Unspecified injury to the head' diagnostic codes made up of 39.5\ua0% of all cases identified with the inclusive case definition. Exclusion of 'unspecified injury to the head' diagnostic code in the TBI case definition resulted in a significantly higher proportion of patients in the intensive care units (p