Objective: To examine the pattern of disease severity in patients with rheumatoid arthritis (RA) at presentation to the Norfolk Arthritis Register (NOAR) over 20 years.
Methods: NOAR is a primary-care-based cohort of patients with recent-onset inflammatory polyarthritis. At baseline, subjects are assessed and examined by a research nurse. The Health Assessment Questionnaire (HAQ) is administered and the DAS28 (28-joint Disease Activity Score) is calculated. Information is collected on disease-modifying antirheumatic drug exposure. In this study, patients (symptom duration of < 2 years at baseline) were grouped into 4 cohorts (Cohort 1: 1990-1994; Cohort 2: 1995-1999; Cohort 3: 2000-2004; Cohort 4: 2005-2008). The American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) 2010 criteria for RA were applied retrospectively at baseline. Regression analyses were used to examine whether calendar year of presentation to NOAR was associated with baseline HAQ and DAS28 scores. Potential confounders included age at symptom onset, sex, rheumatoid factor, and anticyclic citrullinated peptide antibody positivity.
Results: A total of 1724 patients met the ACR/EULAR 2010 RA criteria at baseline. Unadjusted mean DAS28 scores decreased over time. Calendar year of presentation to NOAR was significantly associated with lower DAS28 scores over time [Y = 4.51 + (-0.56 × year) + (0.44 × year(2))]. Although unadjusted median HAQ scores increased over time, calendar year of presentation to NOAR was not significantly associated with HAQ scores [Y = (1.1) + (0.023 × year) + (0.05 × year(2))]. Similar results were observed in each subpopulation of patients.
Conclusion: While baseline disease activity has lessened slightly over time, there has been no improvement in baseline levels of functional disability.
Keywords: CHANGES OVER TIME; DISEASE ACTIVITY; DISEASE SEVERITY; FUNCTIONAL DISABILITY; INCEPTION COHORT; RHEUMATOID ARTHRITIS.