Determining the minimally important difference in the clinical disease activity index for improvement and worsening in early XXXX .

@entity1 @entity309 @entity158
UNASSIGNED: Background Simplified measures to quantify @entity309 ( @entity309 ) disease activity are increasingly used. The minimally clinically important differences (MCID) for some measures, such as the clinical disease activity index (CDAI), have not been well-defined in real-world clinic settings, especially for early @entity309 @entity1 with low/moderate disease activity. Methods Data from Canadian Early Arthritis Cohort @entity1 were used to examine absolute change in CDAI in the first year after enrollment, stratified by disease activity. MCID cutpoints were derived to optimize the sum of sensitivity and specificity versus the gold standard of @entity1 self-reported improvement or worsening. Specificity, positive predictive value and negative predictive values were calculated against @entity1 self-reported improvement (gold standard) and for change in @entity158 , HAQ and DAS28 improvement. Discrimination was examined using area under receiver operator curves (ROC). Similar methods were used to evaluate MCIDs for worsening for @entity1 who achieved low disease activity. Results A total of 578 @entity1 (mean (SD) age 54.1 (15.3) years; 75% @entity1 , median (IQR) disease duration 5.3 (3.3, 8.0) months) contributed 1169 visit pairs to the improvement analysis. The MCID cutpoints for improvement were 12 ( @entity1 starting in high disease activity, CDAI>22), 6 (moderate, CDAI 10-22), and 1 (low disease activity, CDAI <10). Performance characteristics were acceptable using these cutpoints for @entity158 , HAQ, and DAS28. The MCID for CDAI worsening among @entity1 who achieved low disease activity was 2 units. Conclusions These minimally important absolute differences in CDAI can be used to evaluate improvement and worsening and increase the utility of CDAI in clinical practice. This article is protected by copyright. All rights reserved.
