Background/Purpose: To clarify the current status and issues concerning treatment in the early stage of onset in patients with elderly-onset rheumatoid arthritis (RA) in Japan.

Methods: From the 16,086 patients with RA registered in the nationwide RA database “NinJa” (National Database of Rheumatic Diseases in Japan) in 2019, cases with onset of less than 2 years were extracted. Furthermore, these patients were divided into the following 3 groups according to the age of onset; G1 group (< 65 years old, n=464), G2 group (65-74 years old, n=245), and G3 group (≧75 years old, n=255), respectively. Among 3 groups, the differences in disease activity and treatment content were compared. Additionally, these were also compared by the differences in the attending doctor (internist vs orthopedist).

Results: The median value [IQR] of SDAI (5.2 [2.1-11.0] in G1, 5.0 [1.7-10.3] in G2, and 5.2 [1.9-11.3] in G3) and the remission rate by SDAI (38.4%, 38.8%, and 37.6%) were not significantly different among 3 groups. However, the usage rate of MTX (70.0%, 60.0%, and 38.8%) and the mean dosage (mg/w) of MTX (9.1, 8.5, and 7.6) decreased and that of csDMARDs other than MTX (15.7%, 21.2%, and 41.2%) increased as the group changed from G1 to G3. The proportion of patients using multiple DMARDs (including b/tsDMARDs) was not significantly different among 3 groups (30.2%, 26.1%, and 28.7%). The usage rate of b/tsDMARDs (12.7%, 10.6%, and 14.1%) was not different, but that of bDMARDs (9.3%、6.1%、11.4%) was significantly higher in G3 compared to G2. Especially, the selection rate of nonTNFi/(b/tsDMARDs) was high in G3 (28.8%, 34.6%, and 47.2%). The usage rate of steroids (23.5%, 33.1%, and 43.5%) increased in the G1→G3 group, but NSAIDs decreased (41.2%, 32.7%, and 29.8%), inversely.

There were no differences in the remission rate between patients treated by orthopedist (n=108) (39.3%, 40.9%, and 41.7%) and those treated by internist (n=808) (39.7%, 41.3%, and 38.3%). However, the usage rates of MTX were higher (78.7% vs 70.3%, 77.3% vs 60.5%, and 48.0% vs 39.3%) and those of steroid were lower (24.6% vs 23.8%, 13.6% vs 34.0%, and 32.0% vs 39.7%) in patients treated by orthopedist. The usage rate of b/tsDMARDs in G3 was lower in patients treated by orthopedist than those by internist (4.0% vs 15.9%).

Conclusion: In the early stage of onset, elderly-onset RA patients achieved comparable disease activity control and remission rate to younger-onset RA patients. However, there was a large difference in the treatment content, and the usage rate of steroids was particularly high in elderly-onset RA patients. The pros and cons of achieving steroid-dependent remission in elderly-onset RA patients need to be investigated. In Japan, orthopedists also treat RA patients with drugs, but compared to internists, they treated less frequently difficult-to-treat cases in which MTX could not be used and steroid dependence was high.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparison-of-treatment-and-disease-activity-in-the-early-stage-of-onset-in-patients-with-elderly-onset-vs-younger-onset-rheumatoid-arthritis-using-data-of-national-database-of-rheumatic-diseases-in-j/