Risk of Mortality After Spinal Cord Injury: An 8-Year Prospective Study

Abstract 

Krause JS, Zhai Y, Saunders LL, Carter RE. Risk of mortality after spinal cord injury: an 8-year prospective study.

Objective

To evaluate a theoretical model for mortality after spinal cord injury (SCI) by sequentially analyzing 4 sets of risk factors in relation to mortality (ie, adding 1 set of factors to the regression equation at a time).

Design

Prospective cohort study of data collected in late 1997 and early 1998 with mortality status ascertained in December 2005. We evaluated the significance of 4 successive sets of predictors (biographic and injury, psychologic and environmental, behavioral, health and secondary conditions) using Cox proportional hazards modeling and built a full model based on the optimal predictors.

Setting

A specialty hospital.

Participants

Adults (N=1386) with traumatic SCI, at least 1 year postinjury, participated. There were 224 deaths. After eliminating cases with missing data, there were 1209 participants, with 179 deceased at follow-up.

Interventions

Not applicable.

Main Outcome Measures

Mortality status was determined using the National Death Index and the Social Security Death Index.

Results

The final model included 1 environmental variable (poverty), 2 behavioral factors (prescription medication use, binge drinking), and 4 health factors or secondary conditions (hospitalizations, fractures/amputations, surgeries for pressure ulcers, probable major depression).

Conclusions

The results supported the major premise of the theoretical model that risk factors are more important the more proximal they are in a theoretical chain of events leading to mortality. According to this model, mortality results from declining health, precipitated by high-risk behaviors. These findings may be used to target those who are at high risk for early mortality as well as to direct interventions to the particular risk factor.

Key Words: Health, Life expectancy, Mortality, Rehabilitation, Risk, Spinal cord injuries

List of Abbreviations: ASIA-D, Asia Spinal Injury Association, level of injury D, neurologically incomplete injury with motor sparing, BRFSS, Behavioral Risk Factor Surveillance System, HR, hazard ratio, LSQ-R, Life Situation Questionnaire-Revised, OAHMQ, Older Adult Health and Mood Questionnaire, SCI, spinal cord injury, VIF, variance inflation factor