From drug-delivery device to disease management tool: a study of preferences for enhanced features in next-generation self-injection devices

Abstract

Purpose: To quantify rheumatology patient preferences and willingness to pay (WTP) for features differentiating enhanced from standard self-injection devices and to investigate differences among subgroups.

Patients and methods: Patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and axial spondyloarthritis (axSpA) were recruited in the UK. A discrete-choice experiment was used to elicit preferences; respondents were presented with 10 choices between 3 different devices: a free standard disposable device, and 2 hypothetical reusable devices characterized by presence/absence of skin sensor, injection speed control, on-screen instructions, injection reminders, electronic log, and large grip. Every hypothetical device included a cost component to assess WTP for each enhanced feature. A random-parameters logit model was used to estimate preference weights and WTP.

Results: Data were collected from 323 respondents by electronic survey (15/11/2017-15/02/2018; RA: 108; PsA: 103; axSpA: 112). On average, the skin sensor was the most preferred feature (£30), followed by injection speed control, injection reminders, electronic log (~£20 each), on-screen instructions (~£12), and a device with a small, rather than large grip (~£7). Similar preferences for attributes were observed across condition subgroups except for grip size: axSpA patients preferred small grip (~£27); PsA patients preferred large grip (~£19). Overall, respondents preferred reusable devices with all enhanced features (WTP value: £85) over the standard device. RA patients exhibited a higher WTP (£145) than PsA (£102) or axSpA (£62) for the same enhanced device.

Conclusion: Patients positively valued reusable self-injection devices with enhanced features, which may improve patient experience, potentially improving treatment adherence, clinical, and economic outcomes.

Keywords: discrete-choice experiment; patient preference; rheumatology; self-administration; subcutaneous injection.

Figure 1

Example DCE question. The final experimental design included 40 sets of 3 devices split into 4 blocks of 10 hypothetical choice questions. Patients were randomly assigned to 1 block of 10 questions. Questions were randomly ordered to avoid ordering effects.

Figure 2

Total population willingness to pay for each enhanced feature (N=323).

Figure 3

Population subgroup willingness to pay for each enhanced feature. (A) Willingness to pay for each enhanced feature by condition; (B) Willingness to pay for each enhanced feature by disease severity; (C) Willingness to pay to each enhanced feature by self-injection experience.

Figure 4

Sample and subgroup valuation of an enhanced, reusable self-injection device with all enhanced features and large grip compared to a standard disposable device (N=323). A standard disposable self-injection device has no features, small grip, and no out-of-pocket cost associated with it.