Higher risk of poor functional outcome and unfavourable clinical events for late-onset rheumatoid arthritis: results from the IORRA cohort

Abstract

Objectives: To compare treatment outcomes in patients with late-onset RA (LORA) and younger-onset RA (YORA).

Methods: We analyzed patients diagnosed with early RA (disease duration < 2 years) between 2000 and 2016 in the Institute of Rheumatology, Rheumatoid Arthritis (IORRA) cohort. Patients were categorized into LORA (onset at ≥65 years) and YORA (onset at <65 years). The primary outcomes were changes in Clinical Disease Activity Index (CDAI) and Japanese version of the Health Assessment Questionnaire (J-HAQ) at Year 5. The secondary outcomes included the incidence of prespecified adverse events.

Results: Methotrexate, biological disease-modifying anti-rheumatic drugs, and glucocorticoids were used in 70.6, 8.4 and 38.0% of the LORA group (n = 813, median age: 71 years), and 81.6, 19.4 and 32.0% of the YORA group (n = 2457, median age: 51 years). Both groups exhibited significant initial improvements in CDAI and J-HAQ scores. At Year 5, mean CDAI scores were 4.39 and 4.03 for the LORA and YORA groups, respectively. J-HAQ score for YORA remained stable below 0.5 after Year 2, whereas that for LORA worsened progressively. At Year 5, mean J-HAQ scores were 0.56 for LORA and 0.33 for YORA. Patients with LORA had a higher incidence of adverse events, with adjusted hazard ratios of 4.70 for death and 2.58 for malignancy.

Conclusions: Patients with LORA and YORA exhibited similar improvements in disease activity over 5 years; however, those with LORA demonstrated a more pronounced decline in physical function.

Keywords: Clinical Disease Activity Index; Japanese version of the Health Assessment Questionnaire; adverse events; cohort study; late-onset rheumatoid arthritis.