P198 The role of comorbidities alongside patient and disease characteristics on long-term disease activity in RA using UK inception cohort data
Authors: Busby Amanda D , Wason James , Pratt Arthur G , Young Adam , Isaacs John , Nikiphorou Elena 
Published: April 2022

Abstract

Background/Aims
Control of disease activity in Rheumatoid Arthritis (RA) is crucial to prevent long-term joint damage and disability. European Alliance of Associations for Rheumatology (EULAR) guidelines recommend focus on disease activity when measuring health outcomes in people living with RA. Particularly, one of their four overarching principles targets clinical remission, defined as the absence of significant inflammatory disease activity, or low disease activity an acceptable alternative. In EULAR’s most recent guidelines (2014), attention was drawn to the role of comorbidities in RA disease management noting the “potential to preclude treatment intensification”. Besides this, recent work by the EULAR Task Force on difficult-to-treat RA recognises that comorbidities can influence the assessment of inflammatory activity in individuals with RA. This study aimed to identify early predictors of poor disease activity at five and 10 years, focussing on comorbidities alongside clinical/sociodemographic factors at first presentation.

Methods
Patients were recruited from two UK-based RA cohorts; Early Rheumatoid Arthritis Study (ERAS, 1986-2001) and Early Rheumatoid Arthritis Network (ERAN, 2002-2012). Participants were classified into two groups; low (&lt;3.2) and moderate/high (≥3.2) Disease Activity Score (DAS28) at 5/10 years. Clinical information (e.g., rheumatoid nodules, erosions), sociodemographic factors (e.g., ethnicity, deprivation) and comorbidity burden (measured using the Rheumatic Diseases Comorbidity Index [RDCI]) were recorded at baseline and yearly thereafter. Multivariable logistic regression models (outcome; low versus DAS28≥3.2) were fitted using multiple imputation.

Results
2,701 patients with RA were recruited (mean age 56.1 years, 66.9% female); 5-year follow-up data were available for 1,718 (63.4%) and 10-year for 820 (30.4%) patients. A higher proportion of individuals had DAS28≥3.2 values at 10 years than five (65.6% vs 59.7%). In multivariable analyses, baseline RDCI was not associated with DAS28 at five (OR 1.05, 95% CI 0.91 to 1.22) or 10 years (OR 0.99, 95% CI 0.75 to 1.31). Sociodemographic factors (female gender, worse deprivation) and poorer baseline HAQ were associated with DAS28≥3.2 at both timepoints, with no association found with age at onset. Being seropositive was associated with DAS28≥3.2 at 5 but not 10 years of follow-up. Conversely, a relationship existed between presence of erosions at baseline and 10-year DAS28 (OR 1.82, 95% CI 1.16 to 2.85).

Conclusion
This study found no association between baseline comorbidity burden and long-term RA disease activity. However, in models adjusted for comorbidity burden, associations with sociodemographic and clinical factors were demonstrated. These results build upon those relating to functional outcome and will accelerate the identification of those RA patients at increased risk of worse outcomes at initial rheumatology appointment. Additionally, these findings suggest that tailored intervention can be implemented in a timely manner, in line with national and international recommendations, potentially limiting permanent joint damage and disability to improve quality of life for individuals with RA.

Disclosure
A.D. Busby: None. J. Wason: None. A.G. Pratt: None. A. Young: None. J. Isaacs: None. E. Nikiphorou: None.