Consistent with prior literature, an injury-related hospitalization was defined as a hospital discharge with a primary diagnosis of an acute injury (ICD-9 codes 800 to 959). Using codes for external causes of injury (E codes), we excluded records for the following mechanisms: injuries from medical and surgical misadventures (E870 to E879), late effects of injury (E929 or E999), and adverse effects of substances in therapeutic use (E930 to E949) (11).