Discrete choice experiments: An overview of experience to date in haemophilia
Authors: Spoors John , Miners Alec , Cairns John 
Published: May 2022

Abstract

Background
The patient voice is an important consideration in the availability and choice of pharmaceuticals – however, how to capture this complex area and apply it formally within regulation, health technology assessment and reimbursement remains subject to ongoing debate. Patient preference studies such as discrete choice experiments (DCEs) are being utilised more frequently in healthcare and it is anticipated that patient preference data will be incorporated more frequently into regulatory submissions moving forward.

Aim
The aim of this review is to provide an overview of DCEs conducted within haemophilia to date and to consider the key issues in response to a rapidly evolving therapeutic pathway.

Methods
A systematic literature search was undertaken via Ovid MEDLINE and EMBASE CLASSIC + EMBASE. Abstracts were uploaded and analysed via Rayyan systematic review software. Results: Of 478 records identified from the database searches, 12 full text journal articles met the inclusion criteria with a date range from 2005–2021. There have been two published studies exploring haemophilia patient preferences in relation to gene therapy: one DCE and one utilising a threshold technique. Surveyed audiences included physicians, patients, pharmacists, healthcare professionals and caregivers. 50% of the included studies (n=6) were exclusively conducted in the US, whilst 3 recruited participants across multiple countries. The sample size varied considerably between studies with the total sample size ranging from 30 participants to 505 participants. For the studies involving patients and their caregivers, the mean patient age range was 8.2–41.4 years. There was diversity in (a) the scale of the qualitative work undertaken to support the DCEs, (b) the undertaking of pilots, and (c) how extensively these elements were reported in the included studies. There is a notable trend towards using an online web-based format, with 3 out of 4 DCEs since 2019 utilising this approach. The number of attributes observed per DCE ranged from 5–12 with a median of 6 attributes from the included studies. The number of levels per attribute was relatively consistent (range 2–5) with 2–3 (n=4) and 2–4 levels (n=4) being utilised most frequently.

Conclusion
Patient preferences and the methods for capturing these are likely to be subject to ongoing debate as the haemophilia care pathway evolves to offer more therapeutic options with a range of risks and benefits. Whilst techniques such as DCE are effective at quantifying patient preferences, they tell us little about the reasons driving these decisions and the likelihood that they will change in response to temporal or external factors. DCEs could be particularly useful for estimating the uptake of new products and assessing potential budget impact. Accelerated and reformed regulatory processes are likely to increase demand for patient preference studies. There is therefore an increased requirement to ensure that patient advocacy groups (PAGs) are resourced and have the expertise to support these studies alongside other research commitments, and that manufacturers consider collaborative approaches when formally capturing patient preferences.

As more therapeutic options become available in haemophilia care, discrete choice experiment may be a useful means of gauging patient preference
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