Risk and Protective Factors for Cause-Specific Mortality After Spinal Cord Injury.

OBJECTIVE

To investigate the association of multiple sets of risk and protective factors (biographic and injury, socioeconomic, health) with cause-specific mortality after spinal cord injury (SCI).

DESIGN

Retrospective analysis of a prospectively created cohort.

SETTING

Spinal Cord Injury Model Systems facilities.

PARTICIPANTS

Adults (N=8157) with traumatic SCI who were enrolled in a model systems facility after 1973 and received follow-up evaluation that included all study covariates (between November 1, 1995 and October 31, 2006).

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: All-cause mortality was determined using the Social Security Death Index as of January 1, 2014. Causes of death were obtained from the National Death Index and classified as infective and parasitic diseases, neoplasms, respiratory system diseases, heart and blood vessel diseases, external causes, and other causes. Competing risk analysis, with time-dependent covariates, was performed with hazard ratios (HRs) for each cause of death.

RESULTS

The HRs for injury severity indicators were highest for deaths due to respiratory system diseases (highest HR for injury level C1-4, 4.84) and infective and parasitic diseases (highest HR for American Spinal Injury Association Impairment Scale grade A, 5.70). In contrast, injury level and American Spinal Injury Association Impairment Scale grade were relatively unrelated to death due to neoplasms and external causes. Of the socioeconomic indicators, education and income were significantly predictive of a number of causes of death. Pressure ulcers were the only 1 of 4 secondary health condition indicators consistently related to cause of death.

CONCLUSIONS

Injury severity was related to mortality due to infective disease and respiratory complications, suggesting that those with the most severe SCI should be targeted for prevention of these causes. Socioeconomic and health factors were more broadly related to a number of causes of death. Intervention strategies that enhance socioeconomic status and health may also result in reduced mortality due to multiple causes.