Risk Prediction Models for Hospital Mortality of General Medical Patients:A Systematic Review

•The performance and validity of hospital mortality prediction models in general medical patients have not been well appraised.•Hospital mortality prediction models were either developed or validated in all general medical patients or those with infection.•Both general and infection models had high risk of bias with variable performance. No models have been well validated to ensure generalizability and stability of performance.•Further validated models are required to predict mortality and guide mortality reduction interventions. To systematically review contemporary prediction models for hospital mortality developed or validated in general medical patients. We screened articles in five databases, from January 1, 2010, through April 7, 2022, and the bibliographies of articles selected for final inclusion. We assessed the quality for risk of bias and applicability using the Prediction Model Risk of Bias Assessment Tool(PROBAST) and extracted data using the Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies(CHARMS) checklist. Two investigators independently screened each article, assessed quality, and extracted data. From 20,424 unique articles, we identified 15 models in 8 studies across 10 countries. The studies included 280,793 general medical patients and 19,923 hospital deaths. Models included 7 early warning scores, 2 comorbidities indices, and 6 combination models. Ten models were studied in all general medical patients(general models) and 7 in general medical patients with infection(infection models). Of the 15 models, 13 were developed using logistic or Poisson regression and 2 using machine learning methods. Four of 15 models reported on handling of missing values. Four of 10 general models, but none of the infection models, had high discrimination (area under curve >0.8). Only 1 model appropriately assessed calibration. All models had high risk of bias; 4 of 10 general models and 5 of 7 infection models had low concern for applicability for general medical patients. Mortality prediction models for general medical patients were sparse and differed in quality, applicability, and discrimination. These models require hospital-level validation and/or recalibration in general medical patients to guide mortality reduction interventions.