Patients' Preference in Intravitreal Treatment Options for Diabetic Macular Edema: Insights from Discrete Choice Experiment and Willingness to Pay

OBJECTIVES: This study employs a Discrete Choice Experiment (DCE) and Willingness to Pay (WTP) to reveal diabetic macular edema (DME) patient preferences concerning intravitreal treatment options.

METHODS: Six attributes were identified through a literature review, two focus groups, and a best-worst scaling exercise. These attributes include initial injection count, maintenance injection frequency, visual impact, retinal fluid effects, adverse reactions, and cost. Attribute levels were obtained through published clinical trials and drug instructions.

Three DCE schemes, each with 12 choice sets, were created using an orthogonal design in SAS. WTP data was collected by describing available intravitreal injection drugs in China with the mentioned attribute levels, prompting patients to indicate their WTP through a Python-based binary search function. Demographic, disease, and treatment data were also collected.

For DCE, the attributes’ relative importance was examined through a mixed logit model, and latent class analysis explored patient characteristics' influence. WTP data was analyzed using descriptive analysis and a conditional logit model.

RESULTS: The study hasn't yet reached the minimum sample size. Surveys in two cities (Beijing, Tianjin) included 74 patients (mean age 55.8±14.7, 48.6% female, mean DME duration 2.2±2.7 years, and 3.27±2.0 injections in 2023). Preliminary WTP results indicate a mean price of CNY 3753±2305, with Q1 at 1992 and Q3 at CNY 5039.

Initial WTP were significantly impacted by gender, family income, self-assessed visual function, overall health, and perceived disease changes post-treatment. Regarding the attributes, injection count, frequency, improvement in edema and vision, and adverse reactions were associated with WTP.

CONCLUSIONS: The data collection phase for DME patients will continue, with the goal of achieving a sample size of 240 patients from seven cities by March 2024. This research will provide essential insights into patient preferences for intravitreal therapy options, enabling healthcare providers to offer more patient-centric treatment plans.