Predictors of Functional Outcomes After Cervical Spinal Cord Injury From the SCIMS Database: Roles of Segmental Motor Strength, Ethnicity, and Health Literacy

Objectives: To identify individual- and injury-specific factors associated with upper-extremity function at 12 months after spinal cord injury (SCI) among individuals with tetraplegia. Methods: This was a retrospective longitudinal cohort study involving 16 SCI Model Systems (SCIMS) rehabilitation centers across the United States. The cohort was 77.4% male; 67.8% White; 25.0% Black/African American; 11.3% Hispanic. Mean age was 47.3±17.7 years. Outcome measures were the fine-motor and self-care domains of the Spinal Cord Injury-Functional Index (SCI-FI) at 12 months post injury. Least squares regression models examined associations of person-related (age, sex, race, ethnicity, admission weight, health literacy) and injury-related (bilateral upper-extremity motor scores, assessed through ISNCSCI) predictors. A follow-up mediation-regression analysis tested whether health literacy mediated the effect of Hispanic ethnicity on outcomes. Results: Higher right C5 and bilateral C8 motor scores were strongly associated with greater SCI-FI fine-motor function and self-care. Hispanic origin and lower health literacy predicted worse outcomes. Older age was additionally associated with lower self-care function. Mediation analyses showed no mediation effect; health literacy and Hispanic ethnicity were independent predictors of 12-month fine-motor and self-care SCI-FI scores. Conclusion: Fine-motor and self-care function is strongly influenced by right C5 strength for dominant arm reaching and right and bilateral C8 strength for grasp and bimanual prehension. Although improvement in segmental motor strength remains neurobiologically challenging and variable, health literacy is a modifiable factor that can be addressed early post-SCI to better support long-term functional outcomes. Because SCI-FI reflects patient-reported performance, enhancing health literacy may directly improve outcomes of greatest relevance to individuals with tetraplegia.