Complications, health care utilization, and costs in dual diagnosis of traumatic spinal cord injury and traumatic brain injury compared to traumatic spinal cord injury alone

Background Traumatic spinal cord injury (TSCI) and traumatic brain injury (TBI) present their own health challenges and socioeconomic impact. Individuals with dual diagnosis (DD) of the two traumas may have different impacts on outcomes, health care utilization, and costs. Objective To evaluate the outcomes of DD compared to isolated TSCI at initial acute hospital stay and 12 months after discharge across TSCI level and completeness. Design Observational longitudinal study. Setting Merative MarketScan Research Database, 2000–2022. Participants Data were extracted for individuals with TSCI alone and DD who were over 18 years of age. The study cohort was composed of 20,212 individuals with either TSCI alone or DD (TSCI+TBI). Injury level groups consisted of cervical incomplete TSCI (CI: 6310 alone, 3962 with TBI); cervical complete TSCI (CC: 393 alone, 269 with TBI); thoracic incomplete TSCI (TI: 3542 alone, 1014 with TBI); thoracic complete TSCI (TC: 508 alone, 210 with TBI); and lumber/sacral/cauda equina TSCI (LSCE: 3227 alone, 777 with TBI). Interventions Not applicable. Main Outcome Measures Demographics, initial acute hospital outcomes (length of stay, index payments, complications, discharge disposition), and 12‐month postdischarge outcomes (rehabilitation services, complications, overall health care utilization, and 12‐month payments). Results Individuals with DD were predominantly younger, male, and commercially insured . During acute hospitalization, outcomes were worse for cervical and thoracic incomplete injuries and LSCE with DD compared to TSCI alone; CI‐DD had 9% higher rates of overall complications, and LSCE‐DD had 2‐day longer hospital stay. Median hospital payments were 1.5‐ to 2.7‐fold higher across most groups with DD, except for CC. One year after injury, overall complications were 5%–15% higher across all DD groups, with most differences in respiratory, cardiovascular, metabolic, and psychiatric complications. Health care utilization of rehabilitation services, emergency room visits, and 12‐month payments were similar or worse in DD groups compared to TSCI alone. Conclusion Individuals with DD had worse outcomes and higher health care utilization compared to those with isolated TSCI, including increased hospital payments, rehabilitation use, and overall complications in the first year after injury. Our findings highlight the increased burden of DD and contribute knowledge for future treatment decision‐making, resource allocation, and research initiatives.