Phenotype and treatment of elderly onset compared with younger onset rheumatoid arthritis patients in international daily practice

Objective To identify possible differences in baseline characteristics, initial treatment and treatment response between RA patient subgroups based on age at disease onset. Methods Daily practice data from the worldwide METEOR registry were used. Patients (7912) were stratified into three age-groups (age at disease diagnosis 65 years). Initial treatment was compared between the different age-groups. With Cox regression analyses the effect of age-group on time-to-switch from first to second treatment was investigated, and with linear mixed models differences in response to treatment (DAS and HAQ) between the age-groups were assessed, after correction for potential confounders. Results The >65 years age-group included more men, and more seronegative RA with somewhat higher inflammatory markers. Initial treatment choices differed only slightly between the age-groups, and the time-to-switch from initial treatment to the next was similar. DAS and HAQ improvement were dependent on the age-group, reflected by a significant interaction between age-group and outcome. The stratified analysis showed a difference of −0.02 and −0.05 DAS points and, −0.01 and 0.02 HAQ points per month in the 65 year age group, a difference that did not seem clinically relevant. Conclusion In this international study on worldwide clinical practice, patients with RA onset >65 years include more men and seronegative arthritis, and were initially treated slightly differently than younger patients. We observed no clinically relevant differences in timing of a next treatment step, or response to treatment measured by DAS and HAQ.