2024 Volume 36 Issue 2 Pages 131-139
［Objectives］We developed an activity classification of the joint index vector（JIV）for rheumatoid arthritis（RA）using monitoring data of RA cases at our institute and verified its validity.
［Methods］The cut-off index（COI）of the Vxy in the JIV was determined by Receiver Operating Characteristic analysis（ROC）in referring to the Clinical Disease Activity Index（CDAI）disease activity threshold and Health Assessment Questionnaire Disability Index（HAQ-DI）remission criteria, which was simultaneously calculated in RA patients. If there is no significant linear correlation between the CDAI score and the Vxy, ROC was performed based on the correlation between HAQ-DI and the Vxy or Vz within that range, and the activity was classified using the obtained COI. Using this classification method, we compared each activity with respect to indicators such as her CDAI and HAQ-DI.
［Results］A total of 617 patients were studied. There were defined as 0.1>Vxy as remission（REM）, 0.45>Vxy≥0.1 and 0.125≥Vz as low joint activity（LJA）, 1.0>Vxy≥0.45 and Vz>0.125 as moderate joint activity（MJA）, and Vxy≥1.0 was defined as high joint activity（HJA）. The concordance rate with CDAI disease activity criteria was 74.1% for REM, 66.7% for LJA, 49.3% for MJA, and 77.0% for HJA.
［Conclusions］It was suggested that treatment goals could be set based on JIV by classifying JIV as disease activity.
