Intercentre variance in patient reported outcomes is lower than objective rheumatoid arthritis activity measures: a cross-sectional study.

Objective: To assess intercentre variability in the ACR core set measures, DAS28 based on three variables (DAS28v3) and Routine Assessment of Patient Index Data 3 in a multinational study. Methods: Seven thousand and twenty-three patients were recruited (84 centres; 30 countries) using a standard protocol in the Quantitative Standard Monitoring of Patients with RA study. Analysis of variance (ANOVA) and mixed-effect analysis of covariance models were used to model the relationship between study centre and different patient-reported and physician-reported RA activity measures. These models were built to adjust for the remaining ACR core set measure (for each ACR core set measure or each composite index), socio-demographics and medical characteristics. ANOVA and analysis of covariance models yielded similar results, and ANOVA tables were used to present variance attributable to recruiting centre. Results: The proportion of variances attributable to recruiting centre was lower for patient reported outcomes (PROs: pain, HAQ, patient global) compared with objective measures (joint counts, ESR, physician global) in all models. In the full model, variance in PROs attributable to recruiting centre ranged from 1.53% for patient global to 3.71% for HAQ compared with objective measures that ranged from 5.92% for physician global to 9.25% for ESR; and was lower for Routine Assessment of Patient Index Data 3 (2.6%) compared with DAS28v3 (11.75%). Conclusion: Intercentre variability in PROs is lower than objective measures of RA activity demonstrating that PROs may be more comparable across centres, and the need for standardization of objective measures.

Induction of osteoclast-associated receptor, a key osteoclast costimulation molecule, in rheumatoid arthritis.

OBJECTIVE: Osteoclast-associated receptor (OSCAR) is a newly identified osteoclast-specific receptor and is of key importance in the process of osteoclast costimulation. This study was undertaken to define the role of costimulation in osteoclast differentiation during inflammatory arthritis. METHODS: OSCAR expression was assessed in the synovium and peripheral blood monocytes of patients with rheumatoid arthritis (RA), and associations with disease activity were assessed. Serum levels of OSCAR were determined by enzyme-linked immunosorbent assay. In vitro osteoclast assays were performed to characterize the role of OSCAR in human osteoclastogenesis. Cytokine regulation of OSCAR was investigated by reverse transcriptase-polymerase chain reaction. RESULTS: OSCAR was expressed by osteoclasts at the erosion front and by mononuclear cells around synovial microvessels. Flow cytometry revealed enhanced expression of OSCAR in peripheral blood monocytes of RA patients as compared with healthy controls. OSCAR expression was correlated with disease activity and acute-phase reactant concentrations. Serum levels of soluble OSCAR were lower in RA patients than in healthy controls. Monocytes with high OSCAR expression exhibited an enhanced potential to differentiate into osteoclasts. Tumor necrosis factor alpha was identified as the main inducer of OSCAR expression in monocytes. CONCLUSION: These data suggest that the osteoclast costimulation pathway is activated in RA. OSCAR is induced in monocytes of RA patients, facilitating their differentiation into osteoclasts and bone resorption.