Patients' valuation of outcomes after venous thromboembolism

Abstract number: CD133

Locadia^* M., Bossuyt† P. M. M., Stalmeier‡ P. F. M., Sprangers† M. A. G., Bank† I., Middeldorp† S., Büller† H. R., Prins§ M. H.

§Academic Hospital Maastricht, Netherlands ^*Academic Medical Center, Netherlands; †AMC, Netherlands; ‡University of Nijmegen, Netherlands;

To determine the optimal duration of treatment with vitamin K antagonists (VKA) after venous thromboembolism (VTE), patient values of health states related to VTE and its treatment with VKA are, ideally, required. We asked patients to value health outcomes after VTE after an episode of VTE (n = 53), after a major bleeding event during treatment with VKA (n = 23), and after the diagnosis of the post-thrombotic syndrome was established (n = 48). Patients were provided with a written description of eight health states: deep vein thrombosis, pulmonary embolism, gastro-intestinal bleeding, muscular bleeding, nonfatal stroke, post-thrombotic syndrome, treatment with VKA, and no treatment with VKA. The time trade off method was used to assign utilities ranging between 0 (death) and 1 (perfect health) for each health state. There was substantial variability between patients, with largest interquartile range (IQR) for pulmonary embolism. The median utilities ranged from 0.33 (IQR = 0.39) for ‘life after a nonfatal stroke’ to 0.96 (IQR = 0.18) for ‘no VKA treatment’. For ‘pulmonary embolism’ the median utility was 0.63 (IQR = 0.50), for ‘gastro-intestinal bleeding’ 0.65 (IQR = 0.37), for ‘muscular bleeding’ 0.76 (IQR = 0.36) for ‘post-thrombotic syndrome’ 0.82 (IQR = 0.31) for ‘deep vein thrombosis’ 0.84 (IQR = 0.34) and for ‘VKA treatment’ 0.92 (IQR = 0.22). Differences in values were not significantly associated with patient characteristics or type of event experienced. Our results indicate that patients are able to value health states related to VTE and VKA treatment, which can be used for recommendations regarding the duration of treatment. Due to the substantial variability between patients, these recommendations have to be tailored to specific patients' values and concerns.