Background: Long-term studies in rheumatoid arthritis (RA) have reported low inflammation yet high disability over time. It is important to determine which factors are driving this disparity, so appropriate interventions can be used to reduce this gap.
Objectives: To identify a subgroup of people with RA with low inflammation yet high disability over 10 years, and describe their characteristics.
Methods: Data came from two cohorts of inflammatory arthritis with regular assessments over 10 years: the Norfolk Arthritis Register (NOAR, inclusion: ≥2 swollen joints for ≥4 weeks) from the UK and the Etude et Suivi des Polyarthrites Indifférenciées Récentes study (ESPOIR, inclusion: early RA) from France. Participants provided demographic data and completed patient reported outcomes (PROs, including the Health Assessment Questionnaire [HAQ]). The 2-component Disease Activity Score (DAS28-2C)1, a measure of inflammation, was calculated from swollen joint counts and C-reactive protein level. Inclusion criteria for this analyis: <2 years baseline symptom duration; HAQ and DAS28-2C at baseline and one other follow-up; recruited after 1/1/2000. HAQ and DAS28-2C were modelled simultaneously using a multivariate group-based trajectory model, to identify groups of participants with similar trajectories of HAQ and DAS28-2C over 10 years. Baseline demographics and PROs were compared between the trajectory groups using logistic regression. Analyses performed separately in NOAR and ESPOIR.
Results: 1001 NOAR and 767 ESPOIR participants were included. In both cohorts, a four group trajectory model had the best fit (Figure). Two subgroups were identified in each cohort that demonstrated the hypothesised relationship: similar DAS28-2C but differing HAQ scores (red trajectories in Figure), titled “High HAQ” and “Low HAQ” (mean difference in HAQ over follow-up [95% confidence interval (CI)]: NOAR 0.76 [0.73, 0.80]; ESPOIR 0.89 [0.82, 0.96]). At baseline, the High HAQ groups in both NOAR and ESPOIR were older, had a higher proportion of women, and had higher levels of fatigue (NOAR: odds ratio [OR] 1.16 [95% CI 1.06, 1.28]; ESPOIR: OR 1.20 [95% CI 1.05, 1.36] [Table]) and pain (NOAR only).
Conclusion: There is a group of people with RA with high levels of disability, despite low inflammation. These results underline the potential need for pain and fatigue management in people with RA, even when inflammation is low.
References: Hensor et al (2019). Rheumatology (Oxford) 58(8)
Acknowledgements: Thanks to the participants of NOAR and ESPOIR and those working in the recruiting centres
ESPOIR Funding: An unrestricted grant from Merck Sharp and Dohme (MSD) was allocated for the first 5 years of the cohort study. Two additional grants from INSERM supported part of the biological database. The French Society of Rheumatology, Abbvie, Pfizer, Lilly and more recently Fresenius and Biogen supported the ESPOIR cohort study.
Disclosure of Interests: James Gwinnutt Grant/research support from: Research grant from Bristol Myers Squibb unrelated to this project, Sam Norton Consultant of: Pfizer and AstraZeneca, Kimme Hyrich Consultant of: Abbvie, Grant/research support from: Pfizer and BMS, Mark Lunt: None declared, Bernard Combe: None declared, Nathalie Rincheval: None declared, Adeline Ruyssen-Witrand: None declared, Bruno Fautrel: None declared, Jacqueline Chipping: None declared, Alex MacGregor: None declared, Suzanne Verstappen: None declared
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.