Have the 10 year outcomes of patients with early inflammatory arthritis improved in the new millennium compared to the decade before? Results from the Norfolk Arthritis Register

Objective: To compare the 10 year outcome (disease activity, disability, mortality) of two cohorts of patients with inflammatory polyarthritis (IP) recruited 10 years apart.Methods: Patients with IP were recruited to the Norfolk Arthritis Register from 1990-94 (Cohort 1 (C1)) and 2000-04 (Cohort 2 (C2)). Demographic and clinical data were collected at baseline and at years 1, 2, 3, 5, 7 and 10. Longitudinal disease activity (swollen/tender 51 joint counts (SJC51/TJC51)) and disability (HAQ) were compared between the cohorts using population average negative binomial regression and generalised estimating equation analysis respectively. Risk of 10 year mortality was compared between cohorts using Cox models. Risk of cardiovascular (CVD) mortality was compared between cohorts using competing risks analysis. Mortality rate ratios (MRR), adjusted for changes in mortality risk of the general population, were calculated using Poisson regression.Results: In total 1653 patients were recruited (C1 = 1022, C2 = 631). Patients in C2 had 17% lower SJC51 than C1 over ten years (95% CI -23% to -10%) whereas TJC51 and HAQ were comparable. C2 patients had reduced risk of all-cause and CVD mortality compared to C1 (all cause: HR 0.72, 95% CI 0.56 to 0.95; CVD: SHR 0.58, 95% CI 0.37 to 0.93). After accounting for changes in mortality risk in the general population, the difference in mortality was non-significant (all cause: MRR 0.78, 95% CI 0.56 to 1.10; CVD: MRR 0.77, 95% CI 0.48 to 1.24).Conclusion: Disease activity significantly improved in the new millennium, whereas disability and mortality were unchanged.