PCV57 STUDY ON THE ATTRIBUTABLE COSTS OF VENOUS THROMBOEMBOLISM AND BLEEDINGS IN DENMARK. COMPARISON OF THE DIFFERENCE-IN-DIFFERENCE AND THE DIFFERENCE-IN-ACTUAL-COSTS METHODS

Abstract

To estimate the event costs of venous thromboembolism (VTE) episodes in Denmark, and the event costs of VTE-patients having major bleedings (intracranial, gastrointestinal and other). Two approaches to estimate the attributable costs were compared: the difference-in-difference (DiD) method and the difference-in-actual-costs (DiAC) method. The study was designed as a retrospective study utilizing the Danish national registries. All Danish incident patients (2004-2016) with VTE (deep vein thrombosis; ICD-10: DI801-DI803 or pulmonary embolisms; ICD-10: DI26) were compared with four controls without VTE. Furthermore, VTE patients with a major bleeding event within three years after diagnosis were compared with four non-bleeding VTE controls (all controls were propensity matched). Event costs included primary care, outpatient, admission, prescription medicine, home care, and lost production. The DiD-method calculates attributable costs by adjusting patients’ level of costs before the incidence and the general level and development in costs by deducting the average total costs of the controls. The DiAC method only adjusts for the level and development in costs by deducting the average total costs of control. 74,137 VTE patients (average 63 years), of which 4,887 had major bleeding, were included. The societal event costs of VTE the first incident year were €12,915 using the DiD-method and €22,128 using the DiAC method. For major bleedings the first year event costs were €9,376 (DiD) and €24,423 (DiAC). Similar picture is seen in year 2 and 3, although at a lower level. Given the age of the VTE-patients lost production explained a major part of the annual event costs. Except for medicines, all costs were significantly higher for VTE-patients than for controls. Using both methods (DiD/DiAC) the attributable societal event costs of VTE and major bleedings were substantial, especially the first year. The DiD method will result in more conservative results than the DiAC method.