Assessing patients' anticoagulation preferences for the treatment of cancer-associated thrombosis using conjoint methodology.

Low molecular weight heparins have demonstrated superiority over coumarins in the extended treatment of cancer-associated thrombosis and are recommended as first-line therapy in clinical guidelines. Non-vitamin K oral antagonists are yet to be evaluated against low molecular weight heparin for this indication. Nevertheless, a perception that patients favor oral anticoagulants over injections may lead to an increased prescribing of warfarin or non-vitamin K oral antagonists despite the evidence gap. There has been no evaluation of cancer patient preferences for anticoagulants and whether such an evidence gap is an acceptable trade-off for patients prescribed orals. We conducted a study to assess what features are most important to CAT patients regarding their choice of anticoagulant. Two modules were applied: Initial in-depth interviews with 9 patients diagnosed with cancer-associated thrombosis, and thereafter quantitative research, where a further 100 patients completed a choice-based-conjoint exercise, where 15 different scenarios were presented to identify the most important attributes of an anticoagulant. Seventy percent of the patients were treated with injected medication (low molecular weight heparin) and 30% with oral medications. Patients most valued an anticoagulant with minimal interference with their cancer treatment (39%), low thrombosis recurrence rate (24%), and low risk of major bleed (19%). Preference for oral administration over injection had moderate importance (13%). The results show that patients prefer an anticoagulant that does not interfere with their cancer treatment, suggesting the primacy of the cancer disease over venous thromboembolism in these patients. Patients also favor efficacy and safety over convenience of route of administration.