Twenty-Year Outcome and Association Between Early Treatment and Mortality and Disability in an Inception Cohort of Patients With Rheumatoid Arthritis: Results From the Norfolk Arthritis Register

Abstract

Objective: To describe the outcome in patients with rheumatoid arthritis (RA) over 20 years from symptom onset, and to assess the association between early treatment (with disease-modifying antirheumatic drugs/steroids) and mortality and disability during follow-up.

Methods: Patients recruited to the Norfolk Arthritis Register (NOAR) between 1990 and 1994 who met the 2010 American College of Rheumatology/European League Against Rheumatism RA criteria at baseline were included in this analysis. Demographic and clinical variables were collected at baseline and at years 1-3, 5, 7, 10, 15, and 20. Disease activity (swollen joint count [SJC]/tender joint count [TJC]), disability (Health Assessment Questionnaire disability index [HAQ DI]), and mortality over 20 years were determined. Associations between treatment group (early treatment [ET], treatment ≤6 months after symptom onset; late treatment [LT], treatment >6 months after symptom onset; never treatment [NT], no treatment) and mortality and disability were assessed using weighted pooled logistic regression and weighted multilevel mixed-effects linear regression, respectively. Inverse weights were used to account for confounding by indication and censoring.

Results: This study included 602 patients with RA (median age 56 years [interquartile range 44-68 years]; 65.9% women). The median SJCs and TJCs were low during the follow-up period (1-3 swollen joints and 3-6 tender joints). The median HAQ DI score increased after year 1 but remained at low/moderate levels (median 1.25 after year 10). The risk of mortality was reduced in the ET and LT groups compared with that in the NT group. The ET group and the NT group had comparable HAQ DI scores during the follow-up period (β = 0.03, 95% confidence interval [95% CI] -0.06, 0.12), while the HAQ DI score was increased in the LT group (for LT versus NT, β = 0.10 [95% CI 0.02, 0.17]).

Conclusion: The results of this study indicate the importance of early treatment with regard to the long-term outcomes in patients with RA.