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The authors found no evidence for a difference in consistency and reliability between the chained TTO method and the conventional TTO method in the valuation of temporary health states. As direct rating is simpler to administer than both TTO methods, one could consider using direct ratings for the valuation of temporary health states. Biases associated with the conventional and the chained TTO method are discussed.

Stratifying patients according to their socially desirable response set improved the prediction of virological treatment response by self-reported adherence. This finding emphasizes the importance of discussing medication adherence with patients in a non-threatening and non-judgemental way that normalizes non-adherence in order to reduce socially desirable responding.

Determining the optimal duration of vitamin K antagonist (VKA) therapy for patients with venous thromboembolism (VTE) requires a weighting of the benefits and risks of treatment. The objectives of our study were to investigate patient variability in health state valuations associated with VKA therapy and treatment preferences, and to investigate the extent to which valuations and treatment preferences are associated with prior experience with these health states and other patient characteristics. Valuations of outcomes after VTE scaled from 0 (tantamount to death) to 1 (tantamount to perfect health) were elicited from 53 patients who had experienced VTE, 23 patients who had experienced major bleeding during treatment, and 48 patients with the post-thrombotic syndrome. In addition, patients' treatment preferences were evaluated using treatment trade-off questions. Median health state valuations ranged from 0.33 for 'non-fatal haemorrhagic stroke' to 0.96 for 'no VKA treatment'. Variability between patients was substantial. Patients' treatment preferences also varied: 25% of patients chose cessation of treatment, regardless of the probability of recurrent VTE presented, whereas 23% of patients were never willing to choose cessation of treatment. Differences in valuations and treatment preferences were not associated with type of event experienced. Due to the substantial and unpredictable variability in valuations and treatment preferences, recommendations regarding treatment duration should be tailored to patients' specific values and concerns.

Objective In patients with a chronic asymptomatic HIV-1 infection and >200 CD4+ T-cells/μl, the optimal timing of highly active antiretroviral therapy (HAART) initiation is unclear. It involves a trade-off between a potentially reduced risk of mortality, when started earlier in the course of infection, and an earlier exposure to pill burden and potential toxicities. We investigated patients’ preferences for immediate HAART initiation relative to delaying HAART for 1 year. Methods Consecutive patients were asked for their preference during an interview. A hypothetical difference in 3-year mortality risk between both options was systematically varied between 0% and 10% to determine the threshold at which preference would switch to HAART initiation. Results About 30% of patients preferred HAART initiation even if the mortality risk would be equal for both options. Almost 25% always preferred delaying HAART even if this would result in a 10% greater mortality risk. Most treatment guidelines recommend delaying HAART >350 CD4+ T-cells/μl However, at a risk difference between starting and delaying HAART that corresponds with this CD4+ T-cell count, about 50% would prefer to start HAART immediately. Most guidelines recommend starting HAART below 200 CD4+ T-cells/μl However, at a risk difference between both options corresponding with this CD4+ T-cell count, about 40% preferred delaying HAART. Conclusions We found large variation in patients’ preferences. Some patients were more inclined to initiate HAART earlier than the recommended guidelines, whereas others were more inclined to delay HAART. These findings emphasize the need for shared decision-making when deciding on the most optimal timing of HAART initiation in chronic asymptomatic HIV-1 infection.

To cite this article: Depasse F., Gerotziafas G. T., Busson J., Van Dreden P., Samama M.M. Assessment of three chromogenic and one clotting assays for the measurement of synthetic pentasaccharide fondaparinux (Arixtra Synthetic pentasaccharide fondaparinux (Arixtra 1) is the ®rst indirect (antithrombin-dependent) synthetic speci®c factor (F)Xa inhibitor approved in several countries for the prevention of deep vein thrombosis (DVT) in major orthopedic surgery. In addition, ongoing clinical trials aim to prove its ef®cacy for the treatment of DVT and in coronary heart disease (for review see [1,2]). Fondaparinux plasma concentrations obtained in patients treated at prophylactic and therapeutic doses range from 0.1 to 0.5 mg mL À1 and from 0.6 to 1.5 mg mL À1, respectively; in healthy volunteers, the subcutaneous injection of the established prophylactic dose (2.5 mg) is associated with plasma levels at 0.34 AE 0.04 mg mL À1 [3±5]. Although no coagulation monitoring is advocated, accurate assays dedicated to anti-Xa activity measurement should be available. This could be useful in practical use at least in some particular groups of patients, e.g. with renal impairment, during pregnancy, body weight < 50 kg as recommended for LMWHs or in the elderly. Nevertheless, no special assay has been developed for this purpose and the commercial available assays are designed for either unfractionated or low molecular weight heparins. The aim of this work was to evaluate the possibility of using commercially available assays. Three different chromogenic and one clotting assays for the measurement of fondaparinux anti-Xa activity in plasma were evaluated.Normal pool plasma (Normapool 1 , Hyphen BioMed, Neuville sur Oise, France) was spiked with increasing amounts of fondaparinux (Sano®, Paris, France) in order to obtain plasma concentrations ranging from 0 to 10 mg mL À1 . The antithrombin activity level was measured in this range of concentrations using the Berichrom 1 Heparin was used with addition of exogenous bovine antithrombin as provided with the assay and without addition of exogenous antithrombin. In addition to the results expressed in LMWH anti-Xa IU mL À1 , results were registered as raw data, i.e. optical density variation per minute (DOD min À1 ) and clotting time for the chromogenic and the clotting assays, respectively. FXa inhibition for the chromogenic assays was calculated by reporting the DDO min À1 of the considered sample to the DDO min À1 of the normal pool plasma free of fondaparinux considered as baseline. A statistical analysis was performed using an analysis of variance (ANOVA, F-test).All the antithrombin activity levels measured remained in the normal range and were not signi®cantly affected by the addition of fondaparinux.Results expressed in LMWH anti-Xa IU/mL differed signi®cantly (P < 0.01) from an assay to another for the same fondaparinux plasma concentration, e.g. (mean AE SD, n 10) 0.93 AE 0.03 IU mL A linear relationship was obtained for fondaparinux plasma concentrations ranging from 0 up ...

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