Machine learning algorithms performed no better than regression models for prognostication in traumatic brain injury

J Clin Epidemiol. 2020 Jun;122:95-107. doi: 10.1016/j.jclinepi.2020.03.005. Epub 2020 Mar 20.


Objective: We aimed to explore the added value of common machine learning (ML) algorithms for prediction of outcome for moderate and severe traumatic brain injury.

Study design and setting: We performed logistic regression (LR), lasso regression, and ridge regression with key baseline predictors in the IMPACT-II database (15 studies, n = 11,022). ML algorithms included support vector machines, random forests, gradient boosting machines, and artificial neural networks and were trained using the same predictors. To assess generalizability of predictions, we performed internal, internal-external, and external validation on the recent CENTER-TBI study (patients with Glasgow Coma Scale <13, n = 1,554). Both calibration (calibration slope/intercept) and discrimination (area under the curve) was quantified.

Results: In the IMPACT-II database, 3,332/11,022 (30%) died and 5,233(48%) had unfavorable outcome (Glasgow Outcome Scale less than 4). In the CENTER-TBI study, 348/1,554(29%) died and 651(54%) had unfavorable outcome. Discrimination and calibration varied widely between the studies and less so between the studied algorithms. The mean area under the curve was 0.82 for mortality and 0.77 for unfavorable outcomes in the CENTER-TBI study.

Conclusion: ML algorithms may not outperform traditional regression approaches in a low-dimensional setting for outcome prediction after moderate or severe traumatic brain injury. Similar to regression-based prediction models, ML algorithms should be rigorously validated to ensure applicability to new populations.

Trial registration: NCT02210221.

Keywords: Cohort study; Data science; Machine learning; Prediction; Prognosis; Traumatic brain injury.

Publication types

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

MeSH terms

  • Adult
  • Algorithms*
  • Brain Injuries, Traumatic / therapy*
  • Decision Making, Computer-Assisted*
  • Female
  • Glasgow Coma Scale
  • Humans
  • Logistic Models*
  • Machine Learning*
  • Male
  • Middle Aged
  • Models, Statistical
  • Prognosis*

Associated data