Abstract
Objectives: This study aimed to implement a patient-centred and evidence-based approach to develop a novel patient-reported outcome (PRO) instrument to measure fatigue in patients with systemic lupus erythematosus (SLE).
Methods: A three-step mixed methods psychometric (MMP) approach was followed. Steps comprised: (1) first draft item generation and review using interview data; (2) evaluation and refinement of second draft items using mixed methods data, including interview and quantitative data from a phase 2 clinical study in SLE analysed using Rasch Measurement Theory (RMT) analysis; and (3) evaluation of the final FATIGUE-PRO items using RMT and complementary Classical Test Theory (CTT) analyses. Guided by MMP criteria, a team of clinicians and outcome-measurement experts assessed evidence to inform instrument development.
Results: Step 1 culminated in 55 items (n = 39 patients interviewed). Their refinement in Step 2 using mixed methods evidence led to the final FATIGUE-PRO instrument comprising 31 items across three scales of fatigue: physical fatigue (9 items), mental and cognitive fatigue (11 items), and susceptibility to fatigue (11 items). Qualitative (n = 43 patients) and quantitative (n = 106 patients) evidence strongly supported the scales’ content comprehensiveness and targeting, item quality and fit, conceptual uniqueness, and appropriateness of the response scale. The FATIGUE-PRO further benefited from excellent reliability (RMT: 0.92–0.94 and CTT: 0.95–0.96) and supportive evidence of construct validity from assessments against other PROs.
Conclusion: The conceptual advances, comprehensive coverage, and strong psychometric properties of the FATIGUE-PRO will significantly progress the measurement and management of fatigue in SLE, both in clinical trials and routine practice.
Methods: A three-step mixed methods psychometric (MMP) approach was followed. Steps comprised: (1) first draft item generation and review using interview data; (2) evaluation and refinement of second draft items using mixed methods data, including interview and quantitative data from a phase 2 clinical study in SLE analysed using Rasch Measurement Theory (RMT) analysis; and (3) evaluation of the final FATIGUE-PRO items using RMT and complementary Classical Test Theory (CTT) analyses. Guided by MMP criteria, a team of clinicians and outcome-measurement experts assessed evidence to inform instrument development.
Results: Step 1 culminated in 55 items (n = 39 patients interviewed). Their refinement in Step 2 using mixed methods evidence led to the final FATIGUE-PRO instrument comprising 31 items across three scales of fatigue: physical fatigue (9 items), mental and cognitive fatigue (11 items), and susceptibility to fatigue (11 items). Qualitative (n = 43 patients) and quantitative (n = 106 patients) evidence strongly supported the scales’ content comprehensiveness and targeting, item quality and fit, conceptual uniqueness, and appropriateness of the response scale. The FATIGUE-PRO further benefited from excellent reliability (RMT: 0.92–0.94 and CTT: 0.95–0.96) and supportive evidence of construct validity from assessments against other PROs.
Conclusion: The conceptual advances, comprehensive coverage, and strong psychometric properties of the FATIGUE-PRO will significantly progress the measurement and management of fatigue in SLE, both in clinical trials and routine practice.
| Original language | English |
|---|---|
| Pages (from-to) | 3329–3340 |
| Number of pages | 13 |
| Journal | Rheumatology |
| Volume | 61 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - 20 Jan 2022 |
Keywords
- Pharmacology (medical)
- Rheumatology