Depression phenotypes in spinal cord injury and impact on post-injury healthcare utilization and cost: Analysis using a large claim database.

Depression is the most common psychological comorbidity associated with spinal cord injury (SCI) and affects healthcare utilization and costs. This study aimed to use an International Classification of Disease (ICD) and prescription drug-based depression phenotypes to classify people with SCI, and to evaluate the prevalence of those phenotypes, associated risk factors, and healthcare utilization. Retrospective Observational Study Marketscan Database (2000-2019) Individuals with SCI were classified into six ICD-9/10, and prescription drugs defined phenotypes: Major Depressive Disorder (MDD), Other Depression (OthDep), Antidepressants for Other Psychiatric Conditions (PsychRx), Antidepressants for non-psychiatric condition (NoPsychRx), Other Non-depression Psychiatric conditions only (NonDepPsych), and No Depression (NoDep). Except for the latter, all the other groups were referred to as "depressed phenotypes". Data were screened for 24 months pre- and 24 months post-injury depression. None Healthcare utilization and payments There were 9,291 patients with SCI classified as follows: 16% MDD, 11% OthDep, 13% PsychRx, 13% NonPsychRx, 14% NonDepPsych, 33% NoDep. Compared with the NoDep group, the MDD group was younger (54 vs. 57 years old), predominantly female (55% vs. 42%), with Medicaid coverage (42% vs. 12%), had increased comorbidities (69% vs. 54%), had fewer traumatic injuries (51% vs. 54%) and had higher chronic 12-month pre-SCI opioid use (19% vs. 9%) (all  < 0.0001). Classification into a depressed phenotype before SCI was found to be significantly associated with depression phenotype post-SCI, as evidenced by those who experienced a negative change (37%) vs. a positive change (15%,  < 0.0001). Patients in the MDD cohort had higher healthcare utilization and associated payments at 12 and 24 months after SCI. Increasing awareness of psychiatric history and MDD risk factors may improve identifying and managing higher-risk patients with SCI, ultimately optimizing their post-injury healthcare utilization and cost. This method of classifying depression phenotypes provides a simple and practical way to obtain this information by screening through pre-injury medical records.