Treatment preferences of haemophilia patients with inhibitors have not been well documented. This study sought to identify treatment attributes that patients/caregivers consider most important in the USA, inasmuch as those preferences may affect patient adherence to treatment plans. A discrete choice experiment was conducted to elicit treatment preferences. Haemophilia patients with inhibitors, or their caregivers on their behalf, completed a written survey that elicited preferences for treatment features and levels synthesized from the medical literature including: risk of viral transmission, rise in inhibitor titre, reduction in thromboembolic events, number of infusions, preparation time, infusion time/volume, time required to stop bleeding/alleviate pain, use of prophylaxis, use of major surgery and medication cost. Relative importance (RI) of preferences was modelled using a multinomial logit function. Most respondents were male (49 of 51, 96.1%); mean age, 20.7 years (SD = 18.8) and 88.5% of patients had haemophilia type A. The three most important patient-identified treatment attributes were as follows: time required to stop bleeding (RI = 19.3), possibility that the level of inhibitor may rise (RI = 14.3) and risk of contracting a virus from the product (RI = 13.5). Haemophilia patients with inhibitors and their caregivers appear to be willing to accept treatments that may be more inconvenient and painful as long as the treatments are effective in quickly controlling bleeds, do not increase inhibitor levels and do not pose a risk for viral contraction. Study findings provide meaningful input to the clinical community from patients and caregivers and support the importance of physicians understanding their patients' treatment preferences.
