Abstract
Objectives: This study investigated the effects of aging on the estimation of disease activity and physical function in patients with rheumatoid arthritis (RA).
Methods: 777 patients with RA participated in this study. We compared the composite measures, i.e., disease activity score 28 (DAS28), DAS28-CRP, simplified disease activity index, clinical disease activity index, and Japanese Health Assessment Questionnaire (JHAQ) score among groups of patients aged <60 years (A), in their 60s (B), and >70 years (C).
Results: Groups A, B, and C consisted of 225, 259, and 293 patients, respectively. The average age and age of onset were 64.18 and 55.08 years, respectively. All composite measures were significantly higher in group C than in the other groups. There were significant differences in the erythrocyte sedimentation rate (ESR) among the three groups. The JHAQ score was significantly higher in group C than in the other two groups. According to multiple regression analysis using the JHAQ score as a dependent variable, patient age was a significant independent variable, and the parameter estimate was 0.0118.
Conclusions: (1) Elderly and elderly onset patients with RA have increased markedly in Japan. (2) Disease activity can be overestimated in elderly RA patients using composite measures. When evaluating elderly RA patients, elevations of ESR and patient’s global assessment not due to disease activity should be considered. (3) Patient age is an independent factor linked to a higher JHAQ score in elderly patients with RA, and the JHAQ score increases by approximately 0.12 points for every 10 years.
