Modified disease activity scores that include twenty-eight-joint counts development and validation in a prospective longitudinal study of patients with rheumatoid arthritis

TLDR

The study aimed to develop and validate modified disease activity scores incorporating 28‑joint counts and to assess whether disease duration influences their composition. The scores were derived using canonical discriminant analysis and validated for criterion, correlational, and construct validity, with disease‑duration effects examined. The modified DAS discriminated high from low disease activity, showed no effect of disease duration, and performed as well as scores with more extensive joint counts.

Abstract

Objective. The development and validation of Modified Disease Activity Scores (DAS) that include different 28-joint counts. Methods. These scores were developed by canonical discriminant analyses and validated for criterion, correlational, and construct validity. The influence of disease duration on the composition of the DAS was also investigated. Results. No influence of disease duration was found. The Modified DAS that included 28-joint counts were able to discriminate between high and low disease activity (as indicated by clinical decisions of rheumatologists). Conclusion. The Modified DAS are as valid as disease activity scores that include more comprehensive joint counts.