Unveiling the arthritis divide: Exploring treatment response and impact in late-onset vs. young-onset rheumatoid arthritis.

Objectives: The impact of osteoarthritis (OA) on the initial treatment response of rheumatoid arthritis (RA) by treat-to-target practice was compared between the patients with an onset age of ≥65 years old [late-onset RA (LORA)] and those with an onset age of <65 years old [young-onset RA (YORA)].

Methods: A retrospective study was conducted on the patients with RA, who were referred to Department of Rheumatology, Niigata Rheumatic Center without treatment between January 2021 and July 2022. Patients with grade ≥3 OA according to the Kellgren-Lawrence (K-L) classification in either the knee or hand were classified in the OA (+) group and others were in the OA (-) group. The clinical data were compared at diagnosis and 1 year after the initial treatment between the groups for 74 LORA and 59 YORA patients, respectively.

Results: One year after starting treatment in the LORA patients, the OA (+) group had poorer disease activity control and greater disability in several activities of daily living than the OA (-) group. In the YORA patients, there were no differences in activities of daily living disability between the groups.

Conclusions: In the initial treatment of the LORA patients, the prevalence of OA was high, and the impact of OA on LORA was larger than on YORA.