Prediction of bowel management independence after ischemic spinal cord injury

Abstract

Background: Ischemic spinal cord injury (SCI) belongs to the heterogeneous group of non-traumatic SCI, while the course of sensorimotor and functional recovery is comparable to traumatic SCI. Recently, we derived from data of patients with traumatic SCI a valid model to predict an independent and reliable bowel management one year after SCI.

Aim: To evaluate the performance of this model to predict an independent and reliable bowel management one year following ischemic SCI.

Design: Prognostic study - observational study.

Setting: European Multicenter Study about Spinal Cord Injury (EMSCI) ClinicalTrials.gov: NCT01571531.

Population: One hundred and forty-two patients with ischemic SCI of various level and severity of injury.

Methods: The prediction model relied on a single predictor collected within 40 days from injury, the International Standards for Neurological Classification of Spinal Cord Injury total motor score. Bowel outcome one year after SCI derived from the dichotomization of the Spinal Cord Independence Measure (SCIM) item 7 scores. We defined a positive outcome as independent bowel management with regular movements and appropriate timing with no or rare accidents (score of 10 in SCIM version II and score of 8 or 10 in version III).

Results: The model showed a fair discrimination with an area under the receiver operating characteristic (ROC) curve of 0.780 (95% confidence interval=0.702-0.860). In addition, the model displayed an acceptable accuracy and calibration.

Conclusions: The study extends the validity of our rule to patients with ischemic SCI, thus providing the first model to predict an independent and reliable bowel management in this population.

Clinical rehabilitation impact: The model may be employed in clinical practice to counsel patients, to define the rehabilitation aims and to estimate the need of assistance after discharge, as well as in the research field for the optimization of patients' allocation in the design of future clinical trials.

Conflict of interest statement

Conflicts of interest.—The authors certify that there is no conflict of interest with any financial organization regarding the material discussed in the manuscript.

Figures

Figure 1

—A) Receiver operating characteristic curve (ROC) for prediction of independent bowel management 1 year after ischemic SCI based on Mtot within 40 days. The ROC Y-axis indicates the sensitivity (or the true-positive rate; ie, the proportion of positive cases that are correctly identified by the test) and X-axis indicates the false-positive rate (i.e., the proportion of negative cases that are wrongly classified as positive by the test). B) Calibration plot of the model: comparison between observed and predicted probability to reach an independent bowel management 1 year after ischemic SCI. The red spike plot at the bottom gives the distribution of subjects with (1) and without (0) the outcome (independent bowel management one year after SCI). SCI: spinal cord injury, Mtot: ISNCSCI total motor score.