OBJECTIVES: To elicit preferences of injection-naïve patients with type 2 diabetes mellitus (T2DM) for features of glucagon-like peptide-1 receptor agonist (GLP-1RA) injections using a discrete-choice experiment; to test for effect of injection frequency on patient preferences.
METHODS: Injection-naïve adults in the United States with self-reported physician diagnosis of T2DM completed a web-enabled, discrete-choice experiment (DCE). The survey presented patients with a series of 10 choice questions, each including a pair of hypothetical GLP-1RA injection profiles with equivalent efficacy and side effects. Each profile was defined by the following pre-determined attributes identified from patient interviews: frequency of injections (weekly, daily), injection device (multiple-use injection pen, singleuse injection pen, single-use vial and syringe), needle size (shorter and thinner, longer and thicker), need for refrigeration, and injection-site nodules. Choice questions were based on a pre-determined experimental design with known statistical properties allowing for interaction effects between injection frequency and other injection features. Random-parameters logit was used to estimate preferences.
RESULTS: A total of 184 respondents completed the survey; 50% were women and mean age (SD) was 60.8 (11.0) years. Injection frequency was the most important attribute compared with all other attributes in the DCE. Preferences for all injection features were dependent on frequency of injections; that is, the estimated preference parameter on the interaction between injection frequency and each treatment feature was statistically significant. Negative injection features were statistically significantly less important to patients if injections were weekly instead of daily. For all possible injection profiles included in the design, a greater proportion of patients preferred a weekly injection compared with a daily injection.
CONCLUSIONS: In this study, several device attributes were suggested to predict treatment choice in injection-naïve T2DM patients. Results suggest that injection frequency is of primary importance and key to understanding patient preferences for injectable diabetes treatments.
