Optimizing a New Patient-Reported Outcome Instrument for Proliferative Diabetic Retinopathy: A Psychometric Study
Author(s)
Chris Hartford, MPH1, Steven Sherman, MPH2, Aviva GILLMAN, MSc3, Sophie Cleanthous, PhD3, Jasmin Tinsley, BSc3, Stefan Cano, PhD3, Diana Rofail, PhD2, Diana V. Do, MD4.
1Patient-Centered Outcomes Research Senior Manager, Regeneron Pharmaceuticals, Inc., Sleepy Hollow, NY, USA, 2Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA, 3Modus Outcomes, a THREAD Company, London, United Kingdom, 4Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA.
1Patient-Centered Outcomes Research Senior Manager, Regeneron Pharmaceuticals, Inc., Sleepy Hollow, NY, USA, 2Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA, 3Modus Outcomes, a THREAD Company, London, United Kingdom, 4Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA.
OBJECTIVES: The Diabetic Retinopathy Patient Experience Questionnaire (DR-PEQ) is a patient-reported outcome (PRO) instrument developed with qualitative evidence from patients with proliferative diabetic retinopathy (PDR) and designed to optimize measurement of symptoms and impacts of PDR and its treatment. This study aimed to psychometrically validate and refine the DR-PEQ (comprising 85 items, 4 domains and 5 subscales) to optimize the measurement of patient quality of life (QoL) and outcomes in PDR.
METHODS: This was a non-interventional study of 217 adult patients with PDR treated with intravitreal anti-vascular endothelial growth factor therapy or pan-retinal photocoagulation in the US. Participants completed the DR-PEQ and Patient Global Impression of Severity questionnaire online twice, 7-10 days apart, firstly with the National Eye Institute Visual Function Questionnaire-25 and Impact of Vision Impairment, and secondly with the Patient Global Impression of Change questionnaire. Psychometric analysis used Rasch Measurement Theory (RMT) and Classical Test Theory (CTT).
RESULTS: RMT analyses resulted in the removal of 19 items and scale reordering. The revised DR-PEQ demonstrated good targeting (5 scales; items appropriate for 86%-99% of participants), cohesive scales (matching expected and observed scores; 0%-6% item misfit), clear item hierarchy, and high reliability with or without extremes (0.91-0.98 or 0.89-0.98). CTT results showed good discrimination between groups of disease severity (all differences P<0.001), best-corrected visual acuity (differences P≤0.003), age (differences P<0.001 except for treatment experience, P=0.078), and general health (differences P≤0.005); floor and ceiling effects were minimal for all scales apart from Driving (19.4% and 6%, respectively).
CONCLUSIONS: The refined DR-PEQ exhibits strong psychometric properties, potentially supporting its use as a reliable, valid, and comprehensive tool for assessing PDR-related symptoms and impacts on QoL and facilitating meaningful evaluation of patient QoL and treatment benefits. The modular design of the DR-PEQ also allows for targeted assessment of domains most relevant to investigators’ research questions.
METHODS: This was a non-interventional study of 217 adult patients with PDR treated with intravitreal anti-vascular endothelial growth factor therapy or pan-retinal photocoagulation in the US. Participants completed the DR-PEQ and Patient Global Impression of Severity questionnaire online twice, 7-10 days apart, firstly with the National Eye Institute Visual Function Questionnaire-25 and Impact of Vision Impairment, and secondly with the Patient Global Impression of Change questionnaire. Psychometric analysis used Rasch Measurement Theory (RMT) and Classical Test Theory (CTT).
RESULTS: RMT analyses resulted in the removal of 19 items and scale reordering. The revised DR-PEQ demonstrated good targeting (5 scales; items appropriate for 86%-99% of participants), cohesive scales (matching expected and observed scores; 0%-6% item misfit), clear item hierarchy, and high reliability with or without extremes (0.91-0.98 or 0.89-0.98). CTT results showed good discrimination between groups of disease severity (all differences P<0.001), best-corrected visual acuity (differences P≤0.003), age (differences P<0.001 except for treatment experience, P=0.078), and general health (differences P≤0.005); floor and ceiling effects were minimal for all scales apart from Driving (19.4% and 6%, respectively).
CONCLUSIONS: The refined DR-PEQ exhibits strong psychometric properties, potentially supporting its use as a reliable, valid, and comprehensive tool for assessing PDR-related symptoms and impacts on QoL and facilitating meaningful evaluation of patient QoL and treatment benefits. The modular design of the DR-PEQ also allows for targeted assessment of domains most relevant to investigators’ research questions.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
PCR166
Topic
Patient-Centered Research
Topic Subcategory
Instrument Development, Validation, & Translation, Patient-reported Outcomes & Quality of Life Outcomes
Disease
Diabetes/Endocrine/Metabolic Disorders (including obesity), Sensory System Disorders (Ear, Eye, Dental, Skin)