Background Chronic pain represents a substantial health burden and source of disability following traumatic injury. This study investigates factors associated with racial and ethnic disparities in chronic pain.

Methods Prospective, longitudinal, panel study. Seriously injured patients were recruited from two trauma centres in the Northeastern and Southwestern USA. Data from medical records and individual surveys were collected in-hospital, and at 3-month and 12-month postinjury from a balanced cohort of non-Hispanic black, non-Hispanic white and Hispanic patients. We used linear regression to estimate the associations between race and ethnicity and 3-month and 12-month pain severity outcomes. We grouped all available cohort data on factors that theoretically influence the emergence of chronic pain after injury into five temporally ordered clusters and entered each cluster sequentially into regression models. These included: participant race and ethnicity, other demographic characteristics, preinjury health characteristics, acute injury characteristics and postinjury treatment.

Results 650 participants enrolled (Hispanic 25.6%; white 38.1%; black 33.4%). Black participants reported highest relative chronic pain severity. Injury-related factors at the time of acute hospitalisation (injury severity, mechanism, baseline pain and length of stay) were most strongly associated with racial and ethnic disparities in chronic pain outcomes. After controlling for all available explanatory factors, a substantial proportion of the racial and ethnic disparities in chronic pain outcomes remained.

Conclusion Racial and ethnic disparities in chronic pain outcomes may be most influenced by differences in the characteristics of acute injuries, when compared with demographic characteristics and postacute treatment in the year after hospitalisation.