Association of various comorbidity measures with spinal cord injury rehabilitation outcomes

Objective: To investigate the amount of variation in short- and medium-term spinal cord injury (SCI) rehabilitation outcomes explained by various comorbidity measures, over and above patient preinjury characteristics and neurologic and functional status.

Design: Prospective observational cohort study of traumatic SCI patients receiving inpatient rehabilitation and followed up at 1 year postinjury.

Setting: Inpatient rehabilitation and community follow-up at 6 SCI treatment centers.

Participants: Participants (N=1376) included 1032 patients randomly selected for model development and 344 patients selected for cross-validation.

Interventions: Not applicable.

Main outcome measures: Rehabilitation length of stay (LOS), return to acute care during rehabilitation, discharge motor FIM, discharge home, rehospitalization after discharge, 1-year return to work/school and 1-year depression symptomatology, motor FIM, and residence. Comorbidity measures used were case-mix groups tier weights, Charlson Comorbidity Index (CCI), and the Comprehensive Severity Index (CSI).

Results: Multivariable regression analyses, controlling for patient preinjury and injury characteristics, found that the maximum Comprehensive Severity Index (MCSI) was a significant and stronger predictor of LOS, return to acute care during rehabilitation, and 1-year motor FIM compared with the case-mix groups tier weight or the CCI. The admission CSI was a strong predictor of LOS. For rehospitalization after discharge, only the case-mix groups tier weight was significant. No comorbidity measure was significant beyond patient preinjury and injury characteristics for discharge home, discharge motor FIM, living at home, depression symptomatology, major depressive syndrome, and return to work/school.

Conclusions: Patient preinjury and injury characteristics are sufficient to predict most SCI outcomes. For rehabilitation LOS and return to acute care during rehabilitation, one achieves substantially better explanation when taking clinical comorbidity based on the MCSI into account.