Influence of Role Expectancy on Patient-Reported Outcomes Among Patients With Migraine: A Randomized Clinical Trial.

Importance: It is usually assumed that an individual's classification as a patient or a healthy person is determined by the presence or absence of disease, but little is known about whether the mere awareness of being a patient or a healthy control can play an important role for reporting outcomes. Objective: To investigate whether assignment to the role of a patient or a healthy control has an effect on patient-reported outcomes. Design, Setting, and Participants: This single center, double-blind, 3-group randomized clinical trial included consecutive patients from a tertiary headache clinic based at a single center in Germany who were invited to participate between October 2019 and June 2023. Statistical analysis was performed from January to March 2024. Intervention: Patients with migraine were randomized into 2 groups. The first group was told that this study was centered on migraine symptoms, whereas the second group was told that healthy controls were being sought for a study about patients with vertigo. A third group of age- and sex-matched headache-free participants served as controls. All participants viewed 2 standardized roller coaster videos and provided ratings of their perceived levels of motion sickness and dizziness. Main Outcomes and Measures: The primary outcome was self-reported vestibular symptoms. Secondary outcomes included differences in motion sickness, headache burden, and migraine disability. Outcomes were assessed using standardized questionnaires. Results: The final sample included 366 participants: 122 patients with migraine assigned the role of patient (MP) (migraine as patient): mean [SD] age, 37.56 [12.93] years; 105 [86.1%] female), 122 patients with migraine assigned the role of healthy participant (MH) (migraine as healthy): mean [SD] age, 37.03 [13.10] years; 107 [87.7%] female), and 122 headache-free controls (HC): mean [SD] age, 37.55 [11.56] years; 100 [82.0%] female). The assigned role of the individuals with migraine (MP vs MH) had a significant effect on self-disclosure of (1) estimation that symptoms (dizziness) will occur under specific conditions (self-reported vestibular symptoms: 79 MP [64.8%]; 29 MH [23.8%]; 9 HC [7.4%]; P < .001), (2) the increase of such symptoms (dizziness) after viewing the roller coaster video, and (3) the reported frequency (median [IQR] self-reported monthly headache days for MP: 7 [4-15] days; for MH: 5 [2-10] days; P = .008) and severity (median [IQR] migraine disability assessment score for MP: 35 [20-64] points; for MH: 25 [11-47] points; P = .005) of migraine symptoms. Statistically significant changes were also found for self-reported headache frequency and disability caused by migraine. Conclusions and Relevance: This randomized clinical trial found an effect of expectations regarding the role of a patient with respect to clinical and study outcomes. These findings suggest that role expectations should be taken into account when, for example, invasive treatments are discussed. Trial Registration: ClinicalTrials.gov Identifier: NCT06322550.