Rationale, Aims, and Objectives:The majority of hospitalized nonsurgical medical patients receive pharmacological prophylaxis for venous thromboembolism (VTE), and reassessment of changes in thrombosis and bleeding risk factors during hospital admission may represent an opportunity to discontinue unnecessary or unsafe therapy. The use of validated, clinically derived risk assessment models (RAMs) represents a shift towards an individualized, patient-centred approach to VTE prophylaxis. We are interested in using these tools to assess whether risk categories for VTE and bleeding change during admission and to assess whether such changes result in discontinuation of prophylaxis. Our primary objective was to determine whether VTE and bleed risk categories changed during the course of admission to warrant discontinuation of VTE prophylaxis, using the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) VTE and Bleed RAMs, respectively. Secondary objectives were to determine the number of patients whose risk categorizations for VTE and bleeding warranted discontinuation of VTE prophylaxis and to survey whether prophylaxis was continued or discontinued. Methods:A retrospective review was undertaken for a cross-sectional, randomly selected sample of patients who received VTE prophylaxis while admitted to medical wards in a collection of regional hospitals. Results: Of the 351 medical records reviewed, only eight patients (2.3%) changed their VTE risk category and six (1.7%) changed their bleed risk category to warrant discontinuation of VTE prophylaxis. Ninety patients (26%) were at high risk of VTE and low risk of bleed throughout admission, warranting continued VTE prophylaxis. The majority of patients remained at low risk of VTE throughout admission but remained on VTE prophylaxis until discharge. Conclusions: Risk categories for VTE and bleeding for medical patients did not appreciably change throughout hospital admission. Use of VTE RAMs at admission and prior to initiation of therapy should reduce unnecessary prophylaxis in the majority of medical patients who are at low risk of VTE.