“…This study expanded our previous work using machine-learning approaches to improve accuracy of predicting overdose in the subsequent 3 months in a large state Medicaid dataset and broaden applicability of these models across state Medicaid programmes. 5 Our best-performing GBM has several advantages, including handling missing data automatically, no additional feature selection process required prior to the GBM modelling, greater flexibility in hyper parameter tuning to include complex interactions between predictors and outcomes, and often providing better performance compared with other approaches. 3 , 5 We acknowledge, however, that the flexibility during model tuning can be time-consuming and computationally expensive.…”