A clinical prediction model for long-term functional outcome after traumatic spinal cord injury based on acute clinical and imaging factors

J Neurotrauma. 2012 Sep;29(13):2263-71. doi: 10.1089/neu.2012.2417. Epub 2012 Jul 31.

Abstract

To improve clinicians' ability to predict outcome after spinal cord injury (SCI) and to help classify patients within clinical trials, we have created a novel prediction model relating acute clinical and imaging information to functional outcome at 1 year. Data were obtained from two large prospective SCI datasets. Functional independence measure (FIM) motor score at 1 year follow-up was the primary outcome, and functional independence (score ≥ 6 for each FIM motor item) was the secondary outcome. A linear regression model was created with the primary outcome modeled relative to clinical and imaging predictors obtained within 3 days of injury. A logistic model was then created using the dichotomized secondary outcome and the same predictor variables. Model validation was performed using a bootstrap resampling procedure. Of 729 patients, 376 met the inclusion criteria. The mean FIM motor score at 1 year was 62.9 (±28.6). Better functional status was predicted by less severe initial American Spinal Injury Association (ASIA) Impairment Scale grade, and by an ASIA motor score >50 at admission. In contrast, older age and magnetic resonance imaging (MRI) signal characteristics consistent with spinal cord edema or hemorrhage predicted worse functional outcome. The linear model predicting FIM motor score demonstrated an R-square of 0.52 in the original dataset, and 0.52 (95% CI 0.52,0.53) across the 200 bootstraps. Functional independence was achieved by 148 patients (39.4%). For the logistic model, the area under the curve was 0.93 in the original dataset, and 0.92 (95% CI 0.92,0.93) across the bootstraps, indicating excellent predictive discrimination. These models will have important clinical impact to guide decision making and to counsel patients and families.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Disability Evaluation*
  • Follow-Up Studies
  • Humans
  • Linear Models
  • Outcome and Process Assessment, Health Care / methods*
  • Outcome and Process Assessment, Health Care / statistics & numerical data
  • Predictive Value of Tests
  • Prospective Studies
  • Recovery of Function / physiology
  • Registries*
  • Spinal Cord Injuries / diagnosis*
  • Spinal Cord Injuries / mortality
  • Spinal Cord Injuries / rehabilitation*
  • Trauma Severity Indices