Article Text
Abstract
Objective Patients and physicians commonly differ in their assessments of rheumatoid arthritis (RA) activity. Clinically meaningful discordance thresholds or validation of their ability to predict functional outcomes are lacking. We explored whether an unbiased, person-centred latent profile analysis (LPA) approach could classify cases based on patient global assessment (PtGA) and physician global assessment (MDGA) assessments of RA activity. We further examined whether the LPA groups displayed greater differences in clinical outcomes compared with traditional threshold-based groups. Finally, we evaluated whether LPA yielded higher explanatory power for clinical outcomes.
Methods LPA was performed in 618 patients with established RA from a single centre. A threshold-based discordance definition was used as a comparator, with patients classified into concordant (PtGA–MDGA within ± 3 cm), positively discordant (PtGA–MDGA ≥3 cm) and negatively discordant groups (PtGA–MDGA ≤−3 cm).
Results LPA yielded five distinct groups: low PtGA/low MDGA (35.9%), moderate PtGA/moderate MDGA (18.6%), high PtGA/high MDGA (14.7%), high PtGA/low MDGA (23.3%) and low PtGA/high MDGA (7.4%). Groups differed across clinical, physical function, pain, fatigue, health-related quality of life, work productivity and activity impairment outcomes (p<0.001). Concordance groups, in particular, displayed marked heterogeneity in outcomes depending on the magnitude of disease activity reported, with the low/low group faring the best (p<0.001). The LPA solution demonstrated superior explanatory power for all outcomes (p<0.001).
Conclusions We confirmed the validity and advantages of LPA in characterising the relationship between PtGA and MDGA over a conventional threshold-based definition. LPA yielded optimally distinct, clinically meaningful and cohesive groupings, demonstrating superior explanatory power for disease-related outcomes of interest.
- Rheumatoid arthritis
- disease activity
- patient perspective
- outcomes research
This is an Open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
Statistics from Altmetric.com
Footnotes
Contributors All authors were involved in the study design and/or collection, analysis and interpretation of the data, provided critical revision of the manuscript and approved the final version to be submitted for publication.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Not required.
Ethics approval John F Wolf Human Subjects committee, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data are available.