Validation of a New Glucocorticoid-specific Patient-Reported Outcome Questionnaire (the Steroid PRO)
Overview
Authors
Affiliations
Objectives: Glucocorticoids used in the treatment of inflammatory rheumatic conditions can impact on health-related quality of life. An underpinning qualitative study developed a long-list of candidate items for a treatment-specific patient-reported outcome (PRO) measure. The objective of this paper is to determine scale structure and psychometric properties of the Steroid PRO.
Methods: A cross-sectional survey of adults from the UK, USA, Australia and New Zealand, taking glucocorticoids for a rheumatic disease. Initial survey collected demographics, clinical information, 40 Steroid PRO candidate items and EuroQol-5 Dimensions- 5 levels (EQ-5D-5L). Follow-up, 3-5 days later, collected Steroid PRO candidate items and a condition-change ('transition') question. Analysis included Rasch measurement model, exploratory factor analysis (EFA), and hypothesis testing for discriminative validity, convergence validity and test-retest reliability.
Results: Total responses 946: UK n=743 (79%); USA n=139 (15%); Australia/New Zealand n=64 (7%); mean age 57.6 (SD=13.6); 833 (88%) women. Participants with inflammatory arthritis n=197 (21%), connective tissue disease and/or vasculitis n=402 (42%), giant cell arteritis and/or polymyalgia rheumatica n=347 (37%). Twenty-five items were removed due to lack of fit to Rasch model. Of the remaining items, EFA suggested four subscales: Social impact (4 items); Impact on appearance (3 items); Psychological impact (5 items); Treatment concerns (3 items). Rasch modelling supported a four-subscale structure and total score, confirming construct validity and reliability. Hypothesis testing confirmed discriminant and convergence validity. Intraclass correlation coefficient (total score) was 0.809 demonstrating excellent (test-retest) reliability.
Conclusions: The Steroid PRO is a 15-item, valid and reliable scale for measuring the impact of glucocorticoid therapy in people with rheumatic diseases.
Sweeney A, Bridgewater S, Orme J, Sattui S, Sharp M, Richards P BMJ Open. 2025; 15(2):e089225.
PMID: 39909511 PMC: 11800201. DOI: 10.1136/bmjopen-2024-089225.
Bhonsle A, Coughlan T, Graven R, Bussa P, Gingold M, Polkinghorne K Clin Rheumatol. 2024; 44(1):367-375.
PMID: 39671122 DOI: 10.1007/s10067-024-07256-0.