Assessing the utility of the decoy effect on biologic treatment preference

Many patients struggle with choosing and adhering to biologics. Psychological approaches (e.g. decoy effect) may impact patients' choices when selecting a biologic.

Assess whether decoy options influence choice between injectable treatment options.

Following IRB approval, 750 subjects >18 years were recruited through MTurk. Subjects were randomized in a 1:1:1 ratio into the following groups: 1) baseline comparison between a more effective, weekly injection and a less effective, every-three-month injection; 2) baseline with a decoy inferior to the weekly injection; 3) baseline with a decoy inferior to the every-three-month injection. Treatment preference was self-reported and compared using chi-square tests.

Sixty-six percent of subjects preferred the weekly injection versus 34% for the every-three-month injection (group 1). There was a 4% increase in the number of subjects who preferred the weekly injection (70%; group 2; P=0.34) and a 3% increase for the every-three-month injection (37%) when a decoy inferior to them was included (group 3; P=0.56).

Psychological approaches can be used to enhance treatment initiation and adherence. However, the decoy effect did not appear to have a significant impact in this study. Patients' preferences for efficacy versus frequency of injection may be rather fixed.