Psychologic Factors and Risk of Mortality After Spinal Cord Injury
Abstract
Krause JS, Carter R, Zhai Y, Reed K. Psychologic factors and risk of mortality after spinal cord injury.
Objective
To identify the association of 2 distinct psychologic constructs, personality and purpose in life (PIL), with risk of early mortality among persons with spinal cord injury (SCI).
Design
Prospective cohort study with health data collected in late 1997 and early 1998 and mortality status ascertained in December 2005.
Setting
A large rehabilitation hospital in the southeastern United States.
Participants
Adults (N=1386) with traumatic SCI, at least 1 year postinjury.
Interventions
Not applicable.
Main Outcome Measures
We first evaluated the significance of a single psychologic predictor (a total of 6 scales) while controlling for biographic and injury predictors using Cox proportional hazards modeling and subsequently built a comprehensive model based on an optimal group of psychologic variables.
Results
There were a total of 224 (16.2%) observed deaths in the full sample. The total number of deaths was reduced to 164 in the final statistical model (of 1128 participants) because of missing data. All 6 psychologic factors were statistically significant in the model that was adjusted for biographic and injury factors, whereas only 3 psychologic factors were retained in the final comprehensive model, including 2 personality scales (Impulsive Sensation Seeking, Neuroticism-Anxiety) and the PIL scale. The final comprehensive model only modestly improved the overall prediction of survival compared with the model with only biographic and injury variables, because the pseudo-R2 increased from 0.121 to 0.129, and the concordance increased from 0.730 to 0.747.
Conclusions
The results affirm the importance of psychologic factors in relation to survival after SCI.
aCollege of Health Professions, Medical University of South Carolina, Charleston, SC
bDepartment of Biostatistics, Bioinformatics, and Epidemiology, Medical University of South Carolina, Charleston, SC
Correspondence to James S. Krause, PhD, Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, 77 President St, Suite 117, MSC 700, Charleston, SC 29425
Supported by a field initiated grant from the National Institute for Disability and Rehabilitation Research (grant no. H133G030117) and the Model Spinal Cord Injury Systems (grant no. H133N000005) and the National Institutes of Health (1R01 NS 48117-01 A1). The opinions here are those of the grantee and do not necessarily reflect those of the funding agencies.
No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organization with which the authors are associated.
ABSTRACT