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 <45 years, 45-65 years, >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 <45 and 45-65 years age-groups as compared with 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.