Psychological distress mediates the effect of pain on function.

As part of a larger longitudinal study, the current analyses characterize the relationship among pain, psychological distress, and physical function after major lower extremity trauma. Structural equation modeling techniques were utilized to analyze data from a prospective 2-year observational study of 327 patients treated at 8 level I trauma centers. Data were gathered at 3, 6, 12, and 24 months after injury. In the models tested, higher levels of depressive and anxious distress at the preceding time point was related to lower levels of functioning at 6, 12, and 24 months, and higher levels of pain at the preceding time point were related to lower levels of functioning at 6 and 12 months, but not at 24 months. A reverse model in which lower levels of functioning led to higher levels of psychological distress or pain was tested and did not fit the data. The combination of depressive and anxious distress plays an increasingly important role in mediating the impact of pain on physical function as the recovery from lower extremity trauma progresses from early to later stages. Both pain and psychological distress contribute to reduced function during the first year after a serious injury; however, as recovery proceeds, the role of psychological distress in determining function increases. Longitudinal data on patients with severe leg trauma demonstrates that as recovery proceeds, psychological distress plays an increasingly important role in mediating the impact of pain on function.