Martin A. van't Hof

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.

OBJECTIVE: To validate the European League Against Rheumatism (EULAR), the American College of Rheumatology (ACR), and the World Health Organization (WHO)/International League Against Rheumatism (ILAR) response criteria for rheumatoid arthritis (RA). METHODS: EULAR response criteria were developed combining change from baseline and level of disease activity attained during follow up. In a trial comparing hydroxychloroquine and sulfasalazine, we studied construct (radiographic progression), criterion (functional capacity), and discriminant validity. RESULTS: EULAR response criteria had good construct, criterion, and discriminant validity, ACR and WHO/ILAR criteria showed only good criterion validity. CONCLUSION: EULAR response criteria showed better construct and discriminant validity than did the ACR and the WHO/ILAR response criteria for RA.

In a prospective followup study of 147 patients with rheumatoid arthritis of recent onset, we assessed the progression of radiographic evidence of joint damage on films of the patients' hands and feet obtained biannually. Patients were receiving first-line and second-line treatment. Ninety patients were followed up for 3 years, and 57 were followed up for only 2 years. Radiographic damage was determined by a modification of the method described by Sharp, and to ensure comparability of findings, we determined the percentage of damage per joint group (actual score divided by the maximum possible score). After 3 years, radiographic damage was present in 70% of the patients, all of whom could be identified after 1 year of study. Overall, 18-20% of the joints of the hands and feet were affected after 3 years, with relatively little abnormality per joint (approximately 8% of maximum possible score). During the entire followup, more foot joints than hand joints were affected. The rate of progression in the first year was significantly higher than in the second and third years of study, indicating a flattening of the curve of radiographic progression of joint damage.