New Developments in the Psychometric Testing of the Patient-Reported Impact of Dermatological Diseases (PRIDD) Questionnaire: Responsiveness and Minimally Important Change
Author(s)
Allison FitzGerald, BA, BS1, Neuza da Silva Burger, PhD2, Rachael Pattinson, BSc, MSc, PhD3, Nirohshah Trialonis-Suthakharan, Masters4, Jennifer Austin, BA5, Chris Bundy, PhD6, Matthias Augustin, PhD7.
1Director of Operations, GlobalSkin, Ottawa, ON, Canada, 2Institute for Health Services Research in Dermatology and Nursing, Hamburg, Germany, 3School of Dentistry, Cardiff University, Cardiff, United Kingdom, 4Padvocates, Munich, Germany, 5International Alliance of Dermatology Patient Organizations, Ottawa, ON, Canada, 6School of Healthcard Sciences, Cardiff University, Cardiff, United Kingdom, 7Institute for Health Services Research in Dermatology and Nursing, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
1Director of Operations, GlobalSkin, Ottawa, ON, Canada, 2Institute for Health Services Research in Dermatology and Nursing, Hamburg, Germany, 3School of Dentistry, Cardiff University, Cardiff, United Kingdom, 4Padvocates, Munich, Germany, 5International Alliance of Dermatology Patient Organizations, Ottawa, ON, Canada, 6School of Healthcard Sciences, Cardiff University, Cardiff, United Kingdom, 7Institute for Health Services Research in Dermatology and Nursing, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
OBJECTIVES: Patient-Reported Impact of Dermatological Diseases (PRIDD) is a generic measure of the impact of skin conditions on patients’ lives, developed in accordance to COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN). Adding to the strong evidence of reliability and validity, this study aimed to test responsiveness and propose an anchor-based minimally important change (MIC) for the PRIDD measure.
METHODS: This observational longitudinal study consisted of two global online surveys, administered ~6 weeks apart. Adults with a self-reported dermatological condition were recruited through patient organizations and social media, between June 2023 and January 2024. Participants completed the PRIDD measure (16 items assessing physical, life responsibilities, psychological and social impact dimensions) and the Global Perceived Effect (GPE) scale as a global rating of change of the impact of the dermatological condition after 6 weeks. Responsiveness was evaluated by testing differences in PRIDD change scores from survey 1 to survey 2 across the three groups of participants who answered “worse”, “no change” and “improved” to the GPE. MIC corresponded to the PRIDD change score in the subgroup of patients that reported a minimally meaningful improvement in the anchor question.
RESULTS: 587 participants were included in the current analyses, 83.0% female, mean age of 53.3±15.3 years, from 34 different countries (e.g., 33.4% USA, 27.3% UK, 14.7% Canada), and across 63 primary diagnoses (e.g., 20.6% Lichen Sclerosis, 9.4% Hidradenitis Suppurativa, 6.5% Psoriasis). Differences in PRIDD change scores were statistically significant across GPE categories, for the total score (F=29.70, p<0.001, ŋ2=0.09) and for impact dimensions (F=8.72, p<0.001, ŋ2=0.06). Regarding MIC, a change of ≥ -5.34 points in the PRIDD total score can be interpreted as a clinically significant improvement.
CONCLUSIONS: PRIDD was able to detect meaningful changes, e.g., as a result of therapy, making it a suitable outcome measure for use in patient care and clinical trials.
METHODS: This observational longitudinal study consisted of two global online surveys, administered ~6 weeks apart. Adults with a self-reported dermatological condition were recruited through patient organizations and social media, between June 2023 and January 2024. Participants completed the PRIDD measure (16 items assessing physical, life responsibilities, psychological and social impact dimensions) and the Global Perceived Effect (GPE) scale as a global rating of change of the impact of the dermatological condition after 6 weeks. Responsiveness was evaluated by testing differences in PRIDD change scores from survey 1 to survey 2 across the three groups of participants who answered “worse”, “no change” and “improved” to the GPE. MIC corresponded to the PRIDD change score in the subgroup of patients that reported a minimally meaningful improvement in the anchor question.
RESULTS: 587 participants were included in the current analyses, 83.0% female, mean age of 53.3±15.3 years, from 34 different countries (e.g., 33.4% USA, 27.3% UK, 14.7% Canada), and across 63 primary diagnoses (e.g., 20.6% Lichen Sclerosis, 9.4% Hidradenitis Suppurativa, 6.5% Psoriasis). Differences in PRIDD change scores were statistically significant across GPE categories, for the total score (F=29.70, p<0.001, ŋ2=0.09) and for impact dimensions (F=8.72, p<0.001, ŋ2=0.06). Regarding MIC, a change of ≥ -5.34 points in the PRIDD total score can be interpreted as a clinically significant improvement.
CONCLUSIONS: PRIDD was able to detect meaningful changes, e.g., as a result of therapy, making it a suitable outcome measure for use in patient care and clinical trials.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
MSR155
Topic
Methodological & Statistical Research, Patient-Centered Research
Topic Subcategory
PRO & Related Methods
Disease
Rare & Orphan Diseases