The role of comorbidities alongside patient and disease characteristics in long-term disease activity in RA using UK inception cohort data

Objectives Control of disease activity in RA is a crucial part of its management to prevent long-term joint damage and disability. This study aimed to identify early predictors of poor disease activity at 5 and 10 years, focusing on comorbidities and clinical/sociodemographic factors at first presentation. Methods Patients from two UK-based RA cohorts were classified into two groups; low (<3.2) and moderate/high (≥3.2) DAS using 28 joint counts (DAS28) at 5/10 years. Clinical variables (e.g. rheumatoid nodules, erosions), sociodemographic factors (e.g. ethnicity, deprivation) and comorbidities were recorded at baseline and yearly thereafter. The Rheumatic Diseases Comorbidity Index quantified patient comorbidity burden. Binary logistic regression models (outcome low vs moderate/high DAS28) were fitted using multiple imputation. Results A total of 2701 patients living with RA were recruited (mean age 56.1 years, 66.9% female); 5-year data were available for 1718 (63.4%) patients and 10-year data for 820 (30.4%). Baseline Rheumatic Diseases Comorbidity Index was not associated with DAS28 at 5 [odds ratio (OR) 1.05, 95% CI 0.91, 1.22] or 10 years (OR 0.99, 95% CI 0.75, 1.31) in multivariable analyses. Sociodemographic factors (female gender, worse deprivation) and poorer baseline HAQ-Disability Index were associated with DAS28 ≥3.2 at both timepoints. Being seropositive was associated with 5-year DAS28 ≥3.2. Conclusion This study demonstrates an association between sociodemographic and clinical factors and long-term RA disease activity, in models adjusting for comorbidity burden. The findings call for more holistic and targeted patient management in patients with RA and provide insights for more individualized management plans even on first presentation to rheumatology.