Mild traumatic brain injury in the United States, 1998-2000

Primary objective: To determine the incidence and epidemiology of emergency department (ED)-attended mild traumatic brain injury (mTBI) in the US. Research design: Secondary analysis of ED visits for mTBI in the National Hospital Ambulatory Medical Care Survey for 1998-2000. Methods and procedures: MTBI defined by International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes for 'skull fracture', 'concussion', 'intracranial injury of unspecified nature' and 'head injury, unspecified'. Main outcome and results: The average incidence of mTBI was 503.1 100 000, with peaks among males (590 100 000), American Indians Alaska Natives (1,026 100 000) and those