Development of a Patient-Reported Outcome Measure for Chronic Hypoparathyroidism.

Introduction: A patient-reported outcome (PRO) measure specific to chronic hypoparathyroidism is lacking to facilitate the evaluation of treatment. A PRO measure that followed the recommendations of the US Food and Drug Administration (FDA) PRO guidance was created to address key hypoparathyroidism symptoms.

Methods: A literature review was conducted to identify symptoms of hypoparathyroidism and any existing PRO measures appropriate for evaluating these symptoms, followed by concept elicitation interviews involving six individuals with hypoparathyroidism. On the basis of the results of the literature review and interviews, a draft item pool was developed and refined through two sets of cognitive debriefing interviews with six additional patients. A translatability assessment was also conducted to evaluate concepts, phrases, or components of the items that could be problematic in future translations and to identify culturally specific phrasing.

Results: No PRO measures appropriate to address hypoparathyroidism symptoms documented in the literature were identified. Qualitative research participants included 11 women and one man, with an average age of 49 years; the majority (10) of these participants were white. Concept elicitation interview results were generally consistent with the results of the literature review; the most commonly reported symptoms included issues with cognition, often described as "brain fog" (n = 6), muscle cramping (n = 5), tingling (n = 5), and muscle spasms or twitching (n = 4). The initial draft item pool included 20 items; based upon participant feedback, the final Hypoparathyroidism Symptom Diary comprised 13 items and was found to be easily understood and relevant to the participants. No significant issues were identified by the translatability assessment.

Conclusion: The Hypoparathyroidism Symptom Diary was developed following the recommendations of the FDA's PRO guidance. The measure addresses a comprehensive set of symptoms, as well as key impacts of hypoparathyroidism deemed important by patients.

Funding: Shire Human Genetic Therapies, Inc., Lexington, MA, USA, a member of the Takeda group of companies.