Comparison of the efficacy and safety of biologic agents between elderly-onset and young-onset RA patients: the ANSWER cohort study.

The objective of the study was to compare the efficacy and safety of biological disease-modifying antirheumatic drugs (bDMARDs) between elderly-onset rheumatoid arthritis (EORA) and young-onset rheumatoid arthritis (YORA) patients. Patients with rheumatoid arthritis (RA) aged ≧18 years enrolled in a Japanese multicenter observational registry between 2009 and 2018 who had moderate or high disease activity when initiating bDMARDs were included. EORA was defined as RA with onset at 60 or over. After propensity score weighting for differences in confounding factors, generalized estimating equations were used to assess the relationship between the age of RA onset and bDMARD clinical effectiveness at 48 weeks after starting a bDMARD. Among a total of 7183 patients in the registry, 2815 (39.2%) were identified as EORA. The proportion of patients on bDMARDs was lower in the EORA as compared to the YORA (18.3% vs 28.0%, p < 0.001). Of the 989 bDMARD initiators, 364 (36.8%) were identified as EORA. The median follow-up duration was 48 weeks both in the EORA and in the YORA. After adjusting for differences in baseline characteristics between the two age groups, there was no significant difference in Clinical Disease Activity Index scores at 48 weeks (mean difference 1.01, 95% CI = - 0.62 to 2.64, p = 0.22). There was a non-significant trend toward lower remission in EORA (OR = 0.52, 95% CI = 0.24-1.14, p = 0.10), and low disease activity/remission was similar (OR = 0.86, 95% CI = 0.29-2.52, p = 0.77). Drug retention (HR = 0.95, 95% CI = 0.55-1.35, p = 0.78) and discontinuations due to adverse events (HR = 0.78, 95% CI = 0.38-1.18, p = 0.22) were similar between the two age groups after adjustment for confounders. In RA patients initiating bDMARDs, improvements in clinical disease at 48 weeks were similar between EORA and YORA. Drug retention and adverse events discontinuation were similar between the two age groups.