Simultaneous Development of Patient-Reported Outcome Measures for Masseter Muscle Hypertrophy in An Asia Population

To develop Lower Facial Shape Questionnaire (LFSQ) patient-reported outcome (PRO) measures for masseter muscle hypertrophy (MMH) specific to Asian patients using a simultaneous development approach. The LFSQ assesses symptoms, impacts, and satisfaction associated with MMH and follows guidelines for good research practices established by the US Food and Drug Administration (FDA). Participants ≥18 years old with physician-assessed MMH were recruited from Australia, China, Japan, and South Korea. A conceptual framework was developed using literature reviews and participant interviews (concept elicitation [CE]). Concept criteria included frequency and level of bothersomeness, saturation, and clinical relevance. Draft PRO measures were validated for content with cognitive interviews (CIs). All interviews were conducted in local languages. The CE population included 59 participants (mean age 38 years [SD=10], 92% female). The most commonly reported symptoms included prominence of the jaw (64%), square shape (58%), and teeth clenching (56%). Other frequently (>30%) reported concepts included asymmetry, teeth grinding, large facial appearance, and jaw pain. Approximately 50% of patients reported psychosocial impacts such as feeling less attractive, self-conscious, and less confident. Saturation was reached for 94% of concepts. Satisfaction items were subsequently based on relevant symptom and impact concepts. Based on CE, the draft LFSQ consisted of 7 items each for symptoms and impacts, and 9 satisfaction items. The CIs included 20 participants (mean age 34 [SD=11.7], 80% female), most of whom indicated that they would not add additional items and who correctly interpreted the instructions; therefore, revisions were minor. The CE and CI results from this study support the content validity of the LFSQ in assessing the symptoms, impacts, and satisfaction of MMH in Asia patients. The psychometric properties of the LFSQ need to be further evaluated to support validity.