Development of a Content-Valid Patient-Reported Outcome (PRO) Measure for Adults With Glycogen Storage Disease Type 1a (GSD1a): The GSD1a Symptom Diary-Adult Version
Author(s)
Kristen Bibeau, PhD, MSPH1, Geetanjoli Banerjee, PhD, MPH2, Ufuk Coskun, PhD, MA3, Vanja Sikirica, PharmD, MPH1, Frida Alejandra Flores-Silva, MD, MSc4, Maria Armaou, PhD, MSc5, JeeHee Suh, MSc6, Ethan J. Schwartz, B.S.3.
1Moderna, Inc., Princeton, NJ, USA, 2Moderna, Inc., Cambridge, MA, USA, 3ICON Insights, Evidence and Value, Raleigh, NC, USA, 4ICON Insights, Evidence and Value, Mexico City, Mexico, 5ICON Insights, Evidence and Value, Reading, United Kingdom, 6ICON Insights, Evidence and Value, Montreal, QC, Canada.
1Moderna, Inc., Princeton, NJ, USA, 2Moderna, Inc., Cambridge, MA, USA, 3ICON Insights, Evidence and Value, Raleigh, NC, USA, 4ICON Insights, Evidence and Value, Mexico City, Mexico, 5ICON Insights, Evidence and Value, Reading, United Kingdom, 6ICON Insights, Evidence and Value, Montreal, QC, Canada.
OBJECTIVES: To develop a content-valid patient-reported outcome measuring the core signs/symptoms of glycogen storage disease type 1a (GSD1a) in adults, the GSD1a Symptom Diary-Adult Version (GSD1a-SD-Adults).
METHODS: Qualitative concept elicitation/cognitive interviews were conducted with clinicians and adult patients with GSD1a to identify key signs, symptoms, and health-related quality-of-life (HRQoL) impacts, and evaluate the draft GSD1a-SD-Adults. Participants were recruited from the US, Canada, UK, and Australia. Participants rated symptom severity/bothersomeness/relevance on a scale from 0 = “not at all severe/bothersome/relevant” to 10 = “very severe/bothersome/relevant.” Thematic and cognitive descriptive analyses identified important concepts, including signs/symptoms and HRQoL impacts, and assessed relevance, clarity, comprehensiveness, and ease of completion, respectively, of the draft GSD1a-SD-Adults.
RESULTS: Fifteen patient interviews were conducted, representing patients ages 23 to 68 years (mean: 39 years). The most common signs/symptoms were difficulty concentrating (n = 15, 100%), sweatiness/clamminess (n = 15, 100%), fatigue/tiredness (n = 14, 93%), shaking (n = 14, 93%), and muscle weakness (n = 14, 93%), many of which relate to hypoglycemia. Patients reported the two most severe/bothersome symptoms overall as hunger (mean severity rating = 8.0/10, mean bothersomeness rating = 8.0/10) and headaches (mean severity rating = 8.0/10, mean bothersomeness rating = 7.9/10). Cognitive interviews confirmed that participants found the GSD1a-SD-Adults instructions and items clear, relevant (mean relevance rating = 8.7/10), and easy to complete. All participants found the response options and the 24-hour recall period appropriate. Interviews with GSD1a clinical experts (n = 3) further confirmed the relevance and importance of the concepts included in the draft GSD1a-SD-Adults.
CONCLUSIONS: This study elicited and confirmed signs/symptoms of greatest importance to GSD1a patients. From this, a content-valid fit-for-purpose PRO instrument for measuring core signs/symptoms in adult patients with GSD1a was developed, the GSD1a-SD-Adults, which patients and clinicians confirmed was easy to understand/complete. Future research will evaluate its measurement properties.
METHODS: Qualitative concept elicitation/cognitive interviews were conducted with clinicians and adult patients with GSD1a to identify key signs, symptoms, and health-related quality-of-life (HRQoL) impacts, and evaluate the draft GSD1a-SD-Adults. Participants were recruited from the US, Canada, UK, and Australia. Participants rated symptom severity/bothersomeness/relevance on a scale from 0 = “not at all severe/bothersome/relevant” to 10 = “very severe/bothersome/relevant.” Thematic and cognitive descriptive analyses identified important concepts, including signs/symptoms and HRQoL impacts, and assessed relevance, clarity, comprehensiveness, and ease of completion, respectively, of the draft GSD1a-SD-Adults.
RESULTS: Fifteen patient interviews were conducted, representing patients ages 23 to 68 years (mean: 39 years). The most common signs/symptoms were difficulty concentrating (n = 15, 100%), sweatiness/clamminess (n = 15, 100%), fatigue/tiredness (n = 14, 93%), shaking (n = 14, 93%), and muscle weakness (n = 14, 93%), many of which relate to hypoglycemia. Patients reported the two most severe/bothersome symptoms overall as hunger (mean severity rating = 8.0/10, mean bothersomeness rating = 8.0/10) and headaches (mean severity rating = 8.0/10, mean bothersomeness rating = 7.9/10). Cognitive interviews confirmed that participants found the GSD1a-SD-Adults instructions and items clear, relevant (mean relevance rating = 8.7/10), and easy to complete. All participants found the response options and the 24-hour recall period appropriate. Interviews with GSD1a clinical experts (n = 3) further confirmed the relevance and importance of the concepts included in the draft GSD1a-SD-Adults.
CONCLUSIONS: This study elicited and confirmed signs/symptoms of greatest importance to GSD1a patients. From this, a content-valid fit-for-purpose PRO instrument for measuring core signs/symptoms in adult patients with GSD1a was developed, the GSD1a-SD-Adults, which patients and clinicians confirmed was easy to understand/complete. Future research will evaluate its measurement properties.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
PCR58
Topic
Clinical Outcomes, Patient-Centered Research
Topic Subcategory
Instrument Development, Validation, & Translation, Patient-reported Outcomes & Quality of Life Outcomes
Disease
Diabetes/Endocrine/Metabolic Disorders (including obesity), Rare & Orphan Diseases