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Objective: To evaluate the Bristol Rheumatoid Arthritis Fatigue Multidimensional Questionnaire (BRAF-MDQ), the revised Bristol Rheumatoid Arthritis Numerical Rating Scales (BRAF-NRS V2) and the Rheumatoid Arthritis Impact of Disease (RAID) scale in six countries., Methods: We surveyed RA patients in France, Germany, The Netherlands, Spain, Sweden and the UK, including the HAQ, 36-item Short Form Health Survey (SF-36) and potential revisions of the BRAF-NRS coping and Spanish RAID coping items. Factor structure and internal consistency were examined by factor analysis and Cronbach's α and construct validity by Spearman's correlation., Results: A total of 1276 patients participated (76% female, 25% with a disease duration <5 years, median HAQ 1.0). The original BRAF-MDQ four-factor structure and RAID single-factor structure were confirmed in every country with ⩾66% of variation in items explained by each factor and all item factor loadings of 0.71-0.98. Internal consistency for the BRAF-MDQ total and subscales was a Cronbach's α of 0.75-0.96 and for RAID, 0.93-0.96. Fatigue construct validity was shown for the BRAF-MDQ and BRAF-NRS severity and effect scales, correlated internally with SF-36 vitality and with RAID fatigue (r = 0.63-0.93). Broader construct validity for the BRAFs and RAID was shown by correlation with each other, HAQ and SF-36 domains (r = 0.46-0.82), with similar patterns in individual countries. The revised BRAF-NRS V2 Coping item had stronger validity than the original in all analyses. The revised Spanish RAID coping item performed as well as the original., Conclusion: Across six European countries, the BRAF-MDQ identifies the same four aspects of fatigue, and along with the RAID, shows strong factor structure and internal consistency and moderate-good construct validity. The revised BRAF-NRS V2 shows improved construct validity and replaces the original., (© The Author 2017. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Objective: One of the disease hallmarks of RA is progressive cartilage and bone destruction in the joints. The exact mechanism underlying this disease process is largely unknown. Nod1, an intracellular pattern recognition receptor expressed by the innate immune system, has been previously shown to display anti-inflammatory effects in experimental arthritis. Furthermore, an insertion/deletion polymorphism in NOD1 has been demonstrated to modulate cytokine responses of immune cells. In this study, the effect of the insertion/deletion polymorphism in NOD1 on RA susceptibility and severity was assessed., Methods: Ex vivo stimulation of primary immune cells and osteoclasts with microbial triggers was performed to measure cytokine responses and osteoclast-specific gene expression in relation to the NOD1 genotype. In total, 1047 RA patients from two centres were genotyped for the NOD1 polymorphism and compared with 431 healthy controls. Clinical scores of joint inflammation and destruction were correlated with the NOD1 genotype., Results: Functional analysis revealed increased production of pro-inflammatory cytokines in cells from individuals bearing the NOD1 +32656 insertion allele. Furthermore, osteoclast bone resorption activity was elevated, as reflected by increased expression of the lysosomal protease cathepsin K. However, the insertion allele of the NOD1 +32656 polymorphism was not associated with either susceptibility to, or clinical parameters of, inflammation or bone destruction in RA patients., Conclusion: These findings demonstrate that the NOD1 polymorphism modulates pro-inflammatory cytokine responses induced through Toll-like receptor or Nod-like receptor ligands. Nevertheless, these effects of genetic variation in NOD1 appear to be redundant in RA susceptibility and severity.

Background: Despite recent advances, work disability in rheumatoid arthritis (RA) remains common. Work disability is frequently preceded by a period of work instability characterised by a mismatch between an individual's functional abilities and job demands. This could raise the risk of work disability if not resolved. A work instability scale for RA (RA-WIS) has previously been developed to screen for this risk. The objective of this study was the adaptation of this scale into French, Dutch and German., Method: Different language versions of the RA-WIS were produced through a process of forward and back translations. The new scales were tested for face validity. English data from the original developmental study was pooled with data generated through postal surveys in each country. The internal construct and cross-cultural validity of the new scales were assessed using Rasch analysis, including differential item functioning (DIF) by culture., Results: The pooled data showed good fit to the Rasch model and demonstrated strict unidimensionality. DIF was found to be present for six items, but these appeared both to cancel out at the test level and have only a marginal effect on the test score itself., Conclusions: The RA-WIS was shown to be robust to adaptation into different languages. Data fitted Rasch model expectations and strict tests of unidimensionality. This project and the continuing work on further cross-cultural adaptations have the potential to help ensure clinicians across Europe are able to support RA patients to achieve their potential in work through early identification of those most at risk.