Using individual growth curve models to predict recovery and activities of daily living after spinal cord injury: An SCIRehab project study

Objective: To evaluate change in functional outcomes over 1 year after spinal cord injury (SCI). Design: Observational longitudinal secondary analysis. Setting: Six rehabilitation facilities participating in the SCIRehab project. Participants: Patients (N=1146) with SCI enrolled from 2007 to 2010. Interventions: Not applicable. Main Outcome Measures: FIM instrument 13-item and 11-item motor, 3-item transfer, 6-item self-care, 3-item self-care upper-extremity, and 3-item self-care lower-extremity subscores modeled as trajectories of change. Results: Patients were on average 37 years old, non-Hispanic white, with high school or higher education, a body mass index of 25, and a Comprehensive Severity Index score of 20. Most were men with paraplegia (37%) or high tetraplegia (27%). Median time frames were 22 days from injury to admission, 46 days from admission to discharge, 407 days from admission to follow-up, and 44 days for rehabilitation length of stay. The motor subscores were higher on admission for paraplegia and American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade D groups, and recovered faster for the AIS grade D group. Lower function at admission was associated with older age, higher Comprehensive Severity Index score, longer length of stay, fewer physical therapy and therapeutic recreation hours, and more occupational therapy hours. Slower recovery rates were associated with older age, more days from injury to admission, and fewer physical therapy hours per week. Conclusions: Longitudinal outcomes modeled as individual trajectories of change are clinically meaningful. Individual growth curve models could facilitate recovery prediction and outcome evaluation at individual and group levels. However, assessment of the effects of treatment on outcome trajectories will require the addition of outcome measures at time points during intervention and may require the use of outcome measures specific to aspects of rehabilitation, such as mobility and self-care.