Reciprocal Causation Among Pain, Physical Health, and Mental Health 1 Year Post-Traumatic Brain Injury: A Cross-Lagged Panel Model From the TRACK-TBI Study.

OBJECTIVE

To estimate the relative causal influence of physical and mental health on pain in persons with traumatic brain injury (TBI) within the year following injury.

SETTING

Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) was a multicenter study that collected data from 18 level 1 trauma centers around the United States.

PARTICIPANTS

TRACK-TBI recruited adults who experienced an acute TBI. For this secondary analysis, participants were included if they endorsed pain during at least 1 follow-up within 1 year post-TBI.

DESIGN

Secondary analysis using structural equation modeling of the longitudinal TRACK-TBI dataset of an inception cohort.

INTERVENTIONS: None.

MAIN OUTCOMES AND MEASURES: The primary outcomes are pain, physical health, and mental health. Pain was measured by averaging the T-scores of the Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity and Pain Interference scales. Physical and mental health were measured with the raw component scores (physical component score and mental component score, respectively) on the Short Form Health Survey.

RESULTS

Eighty-nine percent of the TRACK-TBI cohort (n = 2022) reported pain throughout 1 year postinjury. This sample (n = 1796) was primarily white (77%) men (67%) in their early forties with mild (87%) closed head injuries (99%) related to motor or road vehicle accidents (57%). Based on the final trimmed model, there was a stronger dominance of pain on physical and mental health than physical and mental health on pain. Thus, pain is a bigger driver of physical and mental health than vice versa.

CONCLUSIONS

Persistent pain is highly prevalent post-TBI and is a bigger driver of physical and mental health 1 year post-TBI than the other way round. Future research should aim to better understand the causes of pain post-TBI to inform what treatments are most effective at reducing pain intensity and interference post-TBI.