Background/Purpose: In the last two decades the treatment in patients with rheumatoid arthritis (RA) has undergone major advances, especially due to the appearance of new therapies, the use of the “treat to target” strategy and a better understanding of the “window of opportunity” concept. However, data from clinical practice confirming the benefits of using these strategies are scarce. Our purpose was to investigate whether the proportion of patients (pts) with RA in maintained remission (R) or low disease activity (LDA) after starting a first biological agent has increased over time and which factors are associated with this change.

Methods: Analysis of a database from a prospective cohort including 365 pts with RA starting a 1st biological agent (BA) (TNF inhibitor, abatacept or tocilizumab) in a tertiary hospital between 2000-2014. Demographic, clinical and analytical data were collected at the beginning of treatment and clinical activity (DAS28) was measured every 6 months. For this study, 3 groups were established according to BA initiation date: interval 1 (i1) (between 2000-2004), (i2) 2005-2009 and (i3) 2010-2014, with a minimum follow-up of 2 years at all pts. For each interval, the percentage of pts achieving maintained (at least 3 consecutive visits) R (DAS28 <2.6) or LDA (DAS28 <3.2) was determined. In addition, all variables collected were compared between groups by ANOVA and chi square test.

Results: Out of the 365 pts initiating a 1st BA, 133 started in i1, 122 in i2 and 110 in i3. Of these, 38% (n=137) achieved maintained R/LDA. This percentage increased significantly in successive intervals (31% in i1 vs, 38% in i2 vs 45% in i3, p=0.02). Baseline characteristics of pts achieving R/LDA are shown in table 1A. For patients in i2 and i3, compared to the previous interval (i1 and i2 respectively), a significant higher frequency of use of BA with different mechanisms of action (0% in i1 vs 2.2% in i2 vs 34% in i3, p <0.001), women (56% in i1 vs 76% in i2 vs 84% in i3, p = 0.01) and concomitant methotrexate (56% in i1 vs 74% in i2 vs 81% in i3, p=0.03) was found. On the other hand, the percentage of optimized pts increased significantly over time (13% in i1 vs 32% in i2 vs 56% in i3, p <0.001; table 1B).

Conclusion: The percentage of pts with RA achieving maintained R/LDA after initiating a 1st BA has progressively increased over time. This is probably related to a greater use of BAs with different mechanisms of action and concomitant methotrexate. The sustained control of disease activity may allow using more frequently optimized doses of BA.