Mismatch between investigator-determined and patient-reported independence after spinal cord injury: consequences for rehabilitation and trials

Abstract

OBJECTIVE:

This study investigated the course and relationship between investigator-determined and patient-reported level of independence within the first year after spinal cord injury (SCI). The authors examined variables that contributed to these scores.
METHODS:

In this observational cohort study, 73 patients with traumatic SCI were evaluated at 1, 3, and 6 months (and 40 subjects at 1 to 12 months). The investigator-determined independence was quantified using the Spinal Cord Independence Measure (SCIM). The subjective, patient-reported independence was determined by asking how their general restrictions influenced everyday life activities. Several variables were used to explain these 2 scores.
RESULTS:

The SCIM score was higher than the patient-reported independence and improved significantly more over time (up to about 70/100 at 12 months), whereas the perceived independence remained below 50/100. The correlations between the 2 measures were at most moderate (r(s) ≤ 0.51), but in general somewhat higher for subjects with tetraplegia. Age and muscle strength predicted the SCIM score well. No variable predicted the patient-reported level of independence.
CONCLUSIONS:

Investigator-determined and patient-reported outcomes can differ considerably and evolve differently. A patient-reported outcome measure may not detect actual functional improvement. It is likely that changes in patient-reported outcomes are influenced by many factors in addition to those associated with functional recovery, including psychological factors.