Predicting the Risk of Venous Thromboembolism in Critically Ill Patients: Validation of Pre-existing Risk Prediction Models and Development of a Prediction Model

Introduction: Venous thrombosis (VTE), including both deep vein thrombosis (DVT) and pulmonary embolism (PE) remains a frequent complication in patients admitted to the Intensive Care Unit (ICU). Multiple prediction models for estimating the risk of VTE have been developed. However, many models have not been externally validated. The aim of this study is to perform a comprehensive external validation of pre-existing prediction models for predicting the risk of in-hospital VTE in critically ill patients. In case current risk assessment models fail, the investigators aim to additionally develop and internally validate a new risk prediction model.

Methods: During the first phase of the study the investigators will perform external validation of existing prediction models. The performance, discrimination, calibration and clinical usefulness of the models will be evaluated. In the second phase of the study, in case performance of current risk assessment models is deemed insufficient for clinical application, the investigators will develop a model for predicting the risk of in-hospital VTE in critically ill patients. A multivariable prediction model will be constructed using a combination of predefined candidate predictors. This model will be internally validated and performance will be compared with performance of existing VTE risk prediction models.

Dissemination: This protocol will be published online. This study will be reported according to the Transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD) statement and this study will be submitted to a peer-reviewed journal for publication.