Differences in quality of life outcomes among depressed spinal cord injury trial participants
Denise G Tate1, Martin Forchheimer1, Charles H Bombardier2
1Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI.
Objective:
To assess the role that treatment response plays in a randomized controlled trial of an antidepressant among people with spinal cord injury (SCI) diagnosed with major depressive disorder (MDD) in explaining quality of life (QOL), assessed both globally as life satisfaction and in terms of physical and mental health-related QOL.
Design:
Multivariable analyses were conducted, controlling for demographic, neurologic, and participatory factors and perceived functional limitations.
Setting:
Rehabilitation centers.
Participants:
Of the 133 persons who were randomized into the Project to Improve Symptoms and Mood after Spinal Cord Injury randomized controlled trial, 124 participated in this study. All participants were between the ages of 18 and 64 years, at least 1 month post-SCI, met the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, criteria for MDD, and completed the core measures used in this study.
Interventions:
Not applicable.
Main Outcome Measures:
The Satisfaction with Life Scale and the physical and mental component summary scores of the Medical Outcomes Study 12-Item Short-Form Health Survey.
Results:
Reduction in depressive symptoms over the course of a 12-week trial was predictive of increased QOL, which was measured as life satisfaction and mental well-being, within the context of other explanatory factors. However, reduction in symptoms did not explain differences in physical well-being among those with MDD. Perceived functional disability explained all 3 indices of QOL.
Conclusions:
Greater recognition has been given to QOL outcomes as endpoints of clinical trials because these often reflect participants' reported outcomes. Our findings support the association of QOL to the reduction of depression symptoms among trial participants. This association differs depending on how QOL is defined and measured, with stronger relations observed with life satisfaction and mental well-being among those diagnosed with MDD. The lack of association between depression and physical well-being may be explained by participants' subjective interpretation of physical well-being after SCI and their expectations and perceptions of improved physical health-related QOL based on the use of assistive technology. Consistent with our findings, pain is likely to play a role in decreasing physical QOL among those with incomplete injuries. Practicing caution is suggested in using physical well-being as an endpoint in trials among people with SCI.