Updating EuroSCORE by including emotional, behavioural, social and functional factors to the risk assessment of patients undergoing cardiac surgery: a study protocol

INTRODUCTION: Conventional risk assessment in cardiac surgery focus on medical and physiological factors and have been developed to predict mortality. Other relevant risk factors associated with increased risk of poor outcomes are not included. Adding non-medical variables as potential prognostic factors to risk assessments direct attention away from specific diagnoses towards a more holistic view of the patients and their predicament. The aim of this paper is to describe the method and analysis plan for the development and validation of a prognostic screening tool as a supplement to the European System for Cardiac Operative Risk Evaluation (EuroSCORE) to predict mortality, readmissions and prolonged length of admission in patients within 90 days after cardiac surgery, as individual outcomes. METHODS AND ANALYSIS: The development of a prognostic screening tool with inclusion of emotional, behavioural, social and functional factors complementing risk assessment by EuroSCORE will adopt the methods recommended by the PROGnosis RESearch Strategy Group and report using the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis statement. In the development stage, we will use data derived from three datasets comprising 1143, 3347 and 982 patients for a prospective cohort study of patients undergoing cardiac surgery, respectively. We will construct logistic regression models to predict mortality, prolonged length of admission and 90-day readmissions. In the validation stage, we will use data from a separate sample of 333 patients planned to undergo cardiac surgery to assess the performance of the developed prognostic model. We will produce validation plots showing the overall performance, area under the curve statistic for discrimination and the calibration slope and intercept. ETHICS AND DISSEMINATION: The study will follow the requirements from the Ethical Committee System ensuring voluntary participation in accordance with the Helsinki declarations. Data will be filed in accordance with the requirements of the Danish Data Protection Agency.