Background/Purpose: In individuals at-risk of RA, the identification of reliable biomarkers for the future development of clinical arthritis is of critical importance for risk-stratification and management of these individuals. Imaging, in particular US and MRI, has demonstrated the potential to predict the development and timing of RA in individuals at-risk, raising important implications on disease prevention studies.

To date, there is no consensus or guideline for the most appropriate investigations to perform in this population and clinicians would often request x-rays for the assessment of joint damage in at-risk individuals who present with hand and foot symptoms. To our knowledge, no previous study has evaluated the role of x-rays in this context. 

The aims of this study were to investigate the prevalence and distribution of bone erosions (BE) in the x-rays of the hands and feet in CCP positive (CCP+) at-risk individuals, and their association with the development of inflammatory arthritis (IA).

Methods: Baseline x-rays of the hands and feet and a full US protocol were performed as part of the current study. X-rays BE were reported as standard by MSK radiologists and confirmed by subsequent reading by a second independent MSK radiologist, blinded to the clinical and US findings. The Simple Erosions Narrowing Score (SENS) was calculated for BE. The presence of US synovitis and BE was explored in the areas in which x-rays BE were reported. A subset of CCP+ individuals (n=73) had repeated x-rays at the time of progression. Subjects with ≥1 follow-up visit were included in the progression analysis (n=394).

Results: The hands and feet x-rays of 418 CCP+ individuals were analysed. X-rays BE were found in 17 (4.1%), most frequently in the feet (64.7% individuals). The median SENS score was 2.0 (IQR: 1.0-2.0). Of the 17 CCP+ individuals with x-rays detected BE, 7 (41.2%) developed IA and 10 (58.8%) did not progress to IA. The clinical and imaging characteristics of the CCP+ individuals with x-rays BE detected are shown in Table 1.

A total of 123/394 (31.2%) CCP+ at-risk individuals developed IA (median follow-up: 336 days; IQR: 167-748). Seven out of 17 (41.2%) individuals with x-rays detected BE, and 116/377 (30.8%) individuals without x-rays detected BE, developed IA (p=0.37) (Figure 1).  New BE were found in only 4/73 (5.4%) CCP+ individuals on repeated x-rays at the time of progression.

Both in the univariable and multivariable analysis, CR detected BE were not predictive for the development of IA [OR: 1.60 (95%CI: 0.60-4.20) p=0.37 and OR: 1.00 (95%CI: 0.30-2.90) p=1.0, respectively], also when these analyses were carried out in individuals with BE in ≥ 3 joints and individuals with radiographic pattern indicating IA (according to the MSK radiologist’s diagnosis). In individuals in which BE were detected by both x-rays and US, borderline results were observed in the univariable analysis [OR=9.08 (95%CI: 1.00-82.06) p=0.05]. 

Conclusion: In CCP+ individuals at-risk of RA, x-rays BE are uncommon and do not predict the development of clinical arthritis. Prevention studies should be able at least to prevent radiographic damage in CCP+ at-risk individuals.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/x-rays-bone-erosions-are-uncommon-in-anti-ccp-positive-individuals-at-risk-of-rheumatoid-arthritis-with-musculoskeletal-symptoms-without-clinical-synovitis-and-do-not-predict-the-development-of-infla/