Multimedia Appendix 1

10b D Specify type of model, all model-building procedures (including any predictor selection), and method for internal validation. Model specification:,5, 7 Model building: 7 10c V For validation, describe how the predictions were calculated. 5, 7 10d D;V Specify all measures used to assess model performance and, if relevant, to compare multiple models. 7 10e V Describe any model updating (e.g., recalibration) arising from the validation, if done. N/A Risk groups 11 D;V Provide details on how risk groups were created, if done. N/A Development vs. validation 12 V For validation, identify any differences from the development data in setting, eligibility criteria, outcome, and predictors. 5-6