Are there differences between young- and older-onset early inflammatory arthritis and do these impact outcomes? An analysis from the CATCH cohort

OBJECTIVE: The aim of this study was to determine the impact of age on disease and remission in suspected early RA (ERA). METHODS: Data from the Canadian Early Arthritis Cohort (CATCH) were examined at baseline, 6 and 12 months. Patients were divided into three groups based on age. Analysis of variance (ANOVA) and regression models were performed to determine the impact of age on the 28-joint DAS (DAS28) and remission at 12 months. RESULTS: A total of 1809 patients were initially assessed: 442 (24.4%) young (<42 years), 899 (49.7%) middleaged (542<64 years) and 468 (25.9%) old (564 years); 72.9% female; 63.8% met 2010 ACR/European League Against Rheumatism (EULAR) classification criteria for RA; symptom duration at first visit 186.0 days; DAS28 4.9; HAQ 1.0; 25.3% had baseline erosions. A significant correlation existed between older age and a lower percentage of females, less positive RF and CCP, fewer meeting RA criteria, shorter symptom duration, more erosions at first visit, higher DAS28 and HAQ at baseline and 12 months and fewer DAS28 remission at 12 months (all P<0.003). The age group did not affect the change in DAS28 and HAQ from 0 to 12 months. Co-morbidities increased with age; more DMARDs, including MTX and steroids, and fewer biologics were used in older age. Age and female had a lesser chance of remission in the regression model. CONCLUSION: In suspected ERA, older-onset patients start and end their first year worse in terms of DAS28 and HAQ, with fewer meeting RA criteria, less remission, more DMARDs and steroids use but less biologics use. However, there were no differences between age groups in the change in DAS28.