AB0427 DIFFERENCES IN DRUG USAGE BETWEEN EORA AND YORA PATIENTS WITH TARGET OF LOW DISEASE ACTIVITY

Abstract

Background Along with the present aging population, development of new therapies such as biological disease-modifying anti-rheumatic drugs for rheumatoid arthritis (RA) has resulted in an increasing number of elderly patients with RA seeking treatment. Furthermore, the onset age of RA has been reported to be trending higher. Elderly onset RA (EORA) is defined as that which develops after 60 years of age, and shown to differ from young onset rheumatoid arthritis (YORA) in regard to background and drug treatment.1 Although many EORA cases have acute onset, cases with polymyalgia rheumatica (PMR)-like symptoms and negative for rheumatoid factor (RF) have recently been observed at a relatively high rate.2 In fact, we have found it occasionally difficult to distinguish between EORA and PMR in clinical settings. For both EORA and YORA patients, treat-to-target (T2T) is necessary, though it is considered that EORA should be treated with the goal of acquiring low disease activity (LDA) from the viewpoint of side-effects of administered therapeutic drugs. Objectives In this study, we examined the number of drugs given to EORA and YORA patients treated for RA at our hospital who achieved LDA. Methods We enrolled 260 patients into the EORA (n=70) and YORA (n=190) groups, and investigated background and treatment protocols. Results As for background, there was a significant difference between the EORA and YORA groups for mean age, mean disease duration, and female ratio, whereas the difference was not significant in regard to antibody positive rate, SDAI, or DAS28-CRP. In those groups, average age was 73.8 and 57.8 years, disease duration was 6.66 and 14.7 years, and female ratio was 62.9% and 83.7%, respectively. Furthermore, RF positivity was 85.3% and 80.7%, and ACPA positivity was 86.5% and 87.7%, respectively, while SDAI was 4.28 and 4.59, and DAS28-CRP was 1.99 and 2.04, respectively (Table 1). As for treatments given to the patients, the rates of prednisolone (PSL) use (37.1% vs. 36.3%), and dosage of methotrexate (MTX) (1.45 vs. 1.41 mg) and its usage rate (55.7% vs. 65.3%) were not significantly different between the groups. On the other hand, MTX weekly administration (2.89 vs. 4.09 mg, p=0.009) and biologics usage rate (32.9% vs. 56.3%, p=0.0012) were significantly lower in the EORA group (Table 2). Conclusion Age of onset of RA has been increasing with the aging of society. Therefore, it is important to consider the features of EORA and YORA when considering therapy. For the present investigation, we considered the goal of treatment to be acquisition of LDA rather than remission, and our findings indicate that EORA patients may be better able to achieve that goal with lower MTX dosage and biological product usage as compared to YORA patients. In addition, EORA patients might achieve LDA with a lower amount of drugs.