AB0676 CROSS-EVALUATIONS OF DISEASE ACTIVITIES AND JOINT AFFECT RATIO AFTER BIOLOGICAL OR TARGETED SYNTHETIC DISEASE-MODIFYING ANTI-RHEUMATIC DRUGS USING THE SIMPLIFIED DISEASE ACTIVITY INDEX SCORE AND THE JOINT INDEX VECTOR SCORES
Authors: I. Yoshii, S. Nishiyama, N. Sawada, T. Chijiwa
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Joint Index Vector (JIV) was developed by Nishiyama<sup>1)</sup>, which evaluates only joint involvement in the whole body of the patient with rheumatoid arthritis (RA), presenting a 3-dimensional coordinate axis. This index is available due to a strong correlation with disease activity, functional ability, and pain status<sup>2)3)</sup>. <h3>Objectives:</h3> We tried to evaluate the validity of JIV for disease activity observation by comparing the time change of scores using the simplified disease activity index (SDAI) after using biological or targeted synthetic disease-modifying anti-rheumatic drugs (b/tsDMARDs) divided by the action. <h3>Methods:</h3> RA patients who used b/tsDMARDs from August 2016 to July 2022 were picked up. Patients were divided by the action of b/tsDMARDs for these: TNF inhibitor (TNF-i), IL-6 inhibitor (IL6-i), CTLA4-Ig, and JAK inhibitor (JAK-i). The SDAI score and the JIV scores at 3 months after the initiation (baseline; BL) were monitored in every patient until one year. JIV consists of 3 components: the Vx on the x-axis represents the upper extremities affect ratio, the Vy on the y-axis represents the lower extremities affect ratio, and the Vz on the z-axis represents the large joint minus small joint affect ratio. The Vxy is a square root of the sum of Vx squared plus Vy squared. Therefore, the XY-axes coordinates of JIV with which a magnitude of joint involvement was represented and Vxy. The newly developed JIV classification criteria (JIV-CC) determined the classification of the JIV scores, and the SDAI classification criteria (SDAI-CC) were also used for disease activity. Time changes of the SDAI score and the JIV scores for each b/tsDMARD action group were compared in the subgroups divided by the JIV-CC or the SDAI-CC. <h3>Results:</h3> A total of 364 cases were studied in these: 167 for TNF-i, 53 for IL6-i, 50 for CTLA4-Ig, and 94 for JAK-i. The mean SDAI score at the BL for each group was 13.7, 11.2, 12.6, and 11.5 for TNF-i, IL6-i, CTLA4-Ig, and JAK-i, respectively. The mean Vxy and Vz at the BL for each group were 0.41 and 0.15, 0.39 and 0.14, 0.48 and 0.19, and 0.41 and 0.15 for TNF-i, IL6-i, CTLA4-Ig, and JAK-i, respectively. Every score in every group decreased as time passed, and the final scores (at one year after; @1Y) of SDAI, Vxy, and Vz for each drug group were 5.38, 0.15, and 0.05 for TNF-i, 4.93, 0.12, and 0.06 for IL6-i, 4.98, 0.16, and 0.03 for CTLA4-Ig, and 4.76, 0.16, and 0.06 for JAK-i, respectively. There were no significant differences between any drug groups. In subgroups, the high joint activity at BL group (HJA) of the JIV-CC who used CTLA4-Ig resulted in significantly higher SDAI, Vxy, and Vz scores @1Y than the other joint activity groups; these are moderate joint activity (MJA), light joint activity group (LJA), and remission group (REM), whereas no other drug group result in significant difference. The HJA group that used IL6-i showed no significant SDAI and Vz scores @1Y but significantly higher Vxy scores. In the SDAI-CC subgroups, there were no significant differences between any disease activity groups in SDAI and Vxy scores @1Y in any drug groups. However, the HDA in the BL group showed a significantly higher Vz score @1Y in every drug group. <h3>Conclusion:</h3> Evaluating disease activity in RA using both JIV and SDAI serves more concise information about joint status than SDAI only. <h3>REFERENCES:</h3> [1] Nishiyama S, et al. J Big Data. 2018;5:37 [2] AB0214 Yoshii I, Nishiyama S. DOI: 10.1136/annrheumdis-2023-eular.858 [3] AB0215 Yoshii I, Nishiyama S. DOI: 10.1136/annrheumdis-2023-eular.1069 <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>