The Michigan Retinal Degeneration Questionnaire: A Patient-Reported Outcome Instrument for Inherited Retinal Degenerations.

PURPOSE: To create a psychometrically validated patient-reported outcome measure for inherited retinal degenerations. DESIGN: Qualitative and quantitative patient-reported outcome (PROs) questionnaire development using item response theory validation. METHODS: One hundred twenty-eight patients with a diagnosis of an inherited retinal degeneration at the Kellogg Eye Center (University of Michigan) were recruited and administered a 166-item questionnaire comprising 7 expert-defined domains. The questionnaire was re-administered 4-16 days later to a subset of 25 participants to assess test-retest variability. Graded response models were fit by Cai's Metropolis-Hastings Robbins-Monro algorithm using the R (version 3.6.3) package mirt. Model data were fit to assess questionnaire dimensionality, to estimate item information, and to score participants. Poorly functioning items were removed, and the model was refit to create the final questionnaire. RESULTS: The psychometrically validated PROs measure was reduced to a 59-item questionnaire measuring 7 unidimesnional domains: central vision, color vision, contrast sensitivity, scotopic function, photopic peripheral vision, mesopic peripheral vision, and photosensitivity. A total of 39 items were removed because of poor factor loading, low item information, poor person-ability differentiation, or high item-level interdependence. This novel questionnaire produces a reliable domain score for person ability that does not show significant test-retest variability across repeated administration. CONCLUSIONS: The final PRO questionnaire, known as the Michigan Retinal Degeneration Questionnaire, is psychometrically validated and available for use in the evaluation of patients with inherited retinal degenerations.

The Michigan Vision-Related Anxiety Questionnaire: A Psychosocial Outcomes Measure for Inherited Retinal Degenerations.

OBJECTIVE: We sought to construct and validate a patient-reported outcome measure for screening and monitoring vision-related anxiety in patients with inherited retinal degenerations. DESIGN: Item-response theory and graded response modeling to quantitatively validate questionnaire items generated from qualitative interviews and patient feedback. METHODS: Patients at the Kellogg Eye Center (University of Michigan, Ann Arbor, Michigan, USA) with a clinical diagnosis of an inherited retinal degeneration (n = 128) participated in an interviewer-administered questionnaire. The questionnaire consisted of 166 items, 26 of which pertained to concepts of "worry" and "anxiety." The subset of vision-related anxiety questions was analyzed by a graded response model using the Cai Metropolis-Hastings Robbins-Monro algorithm in the R software mirt package. Item reduction was performed based on item fit, item information, and item discriminability. To assess test-retest variability, 25 participants completed the questionnaire a second time 4 to 16 days later. RESULTS: The final questionnaire consisted of 14 items divided into 2 unidimensional domains: rod function anxiety and cone function anxiety. The questionnaire exhibited convergent validity with the Patient Health Questionnaire for symptoms of depression and anxiety. This vision-related anxiety questionnaire has high marginal reliability (0.81 for rod-function anxiety, 0.83 for cone-function anxiety) and exhibits minimal test-retest variability (ρ = 0.81 [0.64-0.91] for rod-function anxiety and ρ = 0.83 [0.68-0.92] for cone-function anxiety). CONCLUSIONS: The Michigan Vision-Related Anxiety Questionnaire is a psychometrically validated 14-item patient-reported outcome measure to be used as a psychosocial screening and monitoring tool for patients with inherited retinal degenerations. It can be used in therapeutic clinical trials for measuring the benefit of an investigational therapy on a patient's vision-related anxiety.

Content generation for patient-reported outcome measures for retinal degeneration therapeutic trials.

PURPOSE: Generate content for a patient-reported outcome (PRO) measure for use in future clinical trials for inherited retinal degenerations. METHODS: Patients at the University of Michigan Kellogg Eye Center with a clinical diagnosis of inherited retinal degeneration with varying phenotypes were recruited for interviews. First, in-depth interviews were performed to solicit a wide range of patient experiences pertaining to visual function. Coders qualitatively analyzed the transcripts from these interviews using Atlas.ti software (Version 8.1.3 (522)) to draft questionnaire items. Next, the questionnaire was tested and refined based on participant feedback in cognitive interviews and administrator feedback in the pilot survey administration (pilot interviews). RESULTS: A total of 55 participants with a clinical diagnosis of inherited retinal degeneration were interviewed throughout the three study phases: in-depth interviews (n = 26), cognitive interviews (n = 16), and pilot interviews (n = 13). Coded items were analyzed for frequency of occurrence and related themes, then organized into common domains. Within each domain, PRO items were drafted to address the functional limitations or adaptations experienced by patients. CONCLUSIONS: Items for a PRO measure have been drafted and evaluated for interpretability in the target inherited retinal degeneration patient population. Content validity for the items was established through a process of in-depth interviews, cognitive interviews, and pilot interviews.