Machine-learning-based prediction of disability progression in multiple sclerosis: an observational, international, multi-center study

Abstract

Background: Disability progression is a key milestone in the disease evolution of people with multiple sclerosis (PwMS). Prediction models of disability progression have not yet reached the level of trust needed to be adopted in the clinic. A common benchmark to assess model development in multiple sclerosis is also currently lacking. Methods: Data of adult PwMS with a follow-up of at least three years from 146 MS centers, spread over 40 countries and collected by the MSBase consortium was used. With basic inclusion criteria for quality requirements, it represents a total of 15,240 PwMS. External validation was performed and repeated five times to assess the significance of the results. TRIPOD guidelines were followed. Confirmed disability progression after two years was predicted, with a confirmation window of six months. Only routinely collected variables were used such as the expended disability status scale, treatment, relapse information, and MS course. To learn the probability of disability progression, state-of-the-art machine learning models were investigated. The discrimination performance of the models is evaluated on their area under the receiver operator curve (ROC-AUC) and under the precision recall curve (AUC-PR), and their calibration via the Brier score and the expected calibration error. Findings: A temporal attention model was the best model. It achieved a ROC-AUC of 0.71 ± 0.01, an AUC-PR of $0.26 ± 0.02$, a Brier score of $0.1 ± 0.01$ and an expected calibration error of $0.07 ± 0.04$. The history of disability progression is more predictive for future disability progression than the treatment or relapses. Interpretation: Good discrimination and calibration performance on an external validation set is achieved, using only routinely collected variables. This makes these models ready for a clinical impact study. % in MS centers participating in MSBase. All our preprocessing and model code is available at https://gitlab.com/edebrouwer/ms_benchmark, making this task an ideal benchmark for predicting disability progression in MS.