Validation of American College of Rheumatology classification criteria for knee osteoarthritis using arthroscopically defined cartilage damage scores.

OBJECTIVE: To validate the ability of the American College of Rheumatology (ACR) clinical classification criteria and the ACR clinical plus radiographic classification criteria for osteoarthritis of the knee to predict articular cartilage damage. METHODS: Ninety subjects with knee osteoarthritis (OA) who were enrolled in a prospective study determining the therapeutic efficacy of arthroscopic irrigation were characterized as to whether they fulfilled the ACR clinical classification criteria or the ACR clinical plus radiographic classification criteria. Ten rheumatoid arthritis (RA) patients were included as controls. Cartilage damage was defined using the ACR/Knee Arthroscopy Osteoarthritis Scale (ACR/KAOS) system, which is a validated outcome instrument for knee OA based on arthroscopic visualization. Mean values of the damage scores in each group were calculated and compared by t-test to determine statistical significance between the 3 groups. RESULTS: The mean ACR/KAOS score for the 10 RA patients was 1.8 [SD 1.22; range 0 to 4]. Of the 90 OA patients who underwent arthroscopy, only 73 patients had sufficient videotape to make an accurate assessment by the blinded assessor. The mean ACR/KAOS score for the 6 OA patients who fulfilled only the ACR clinical classification was 17.4 [SD 11.3; range 5 to 34.3] and the mean ACR/KAOS score for the 67 patients who fulfilled the ACR clinical plus radiographic classification criteria was 42.0 [SD 29.1; range 5.1 to 118.4]. These differences were statistically significant (RA versus OA clinical P=0.02; RA versus OA clinical+radiographic P

Defining response in systemic lupus erythematosus: a study by the Systemic Lupus International Collaborating Clinics group.

OBJECTIVE: In a preliminary attempt to develop a drug responder index for patients with systemic lupus erythematosus (SLE), 2 validated disease activity instruments were studied for their responsiveness and compared to a physician visual analog scale (VAS) assessment of disease activity. We attempted to determine whether these validated instruments were useful components in characterizing response in the setting of a clinical trial. METHODS: Eighty paper patients were assessed using the British Isles Lupus Assessment Group (BILAG) and Systemic Lupus Disease Activity Index (SLEDAI) and by physician's assessment of global activity. The cases were arranged in random order and divided into groups of 20 patients and each group was assessed by 20 lupus experts; change in disease activity was recorded at 3 and 6 months compared to baseline using a physician VAS. RESULTS: Four different lupus experts assessed disease activity in all 80 patients at baseline and 3 and 6 months after initiation of therapy using the BILAG and SLEDAI instruments. BILAG and SLEDAI scores correlated well over time; however, in a regression analysis where average physician VAS were chosen as the outcome variable, a significant amount of variation in the average physician VAS not related to the SLEDAI and BILAG scores was noted. CONCLUSION: The physician VAS may be too blunt to assess response in SLE, because even among experienced lupus assessors, there were considerable differences in what influenced scoring decisions.