Background/Purpose: In a cohort of Anti-Cyclic Citrullinated Peptide Positive (Anti-CCP+) At-Risk of developing inflammatory arthritis (IA) individuals without clinical synovitis, previous univariable analysis showed that the presence of a Power Doppler signal (PD) in at least one joint was predictive of progression (Nam, 2016).

Further analysis is required to examine the influence of the number of joints PD positive on the progression rates and incorporate this data in the already established 2010 ACR/EULAR criteria for Rheumatoid Arthritis (RA), replacing the swollen joint count by the PD positive joint count.
Objectives:

1. To investigate the association between the number of joints with a Power Doppler signal and progression to IA.
2. To include the PD positive joint count in the 2010 ACR/EULAR criteria for RA to improve prediction in individuals without synovitis.

Methods: Participants were selected by an anti-CCP positive test and a new musculo-skeletal symptom. Individuals with intermittent symptoms or clinical synovitis were excluded.

Using univariable cox regression, we described for the first time the predictive value of the number of joints with a Power Doppler signal.

By replacing the number of swollen joints, with the number of joints PD positive in the 2010 ACR/EULAR criteria for RA, we then analysed IA-free survival curves for participants without clinically swollen joints.

Results: 361 patients were followed for a mean of 24 months (Table 1). Of the 28% of participants who developed IA, 81% met the ACR/EULAR criteria for RA at progression. There were significantly more participants with high anti-CCP titres in the progressor group.
Using Cox univariable analysis, the results show that the probability of developing IA is significantly increased by a Hazard ratio of 1.89 if 1 to 3 small joints present a PD signal (p=0.012), and of 3.81 if 4 to 10 joints are PD positive (p< 0.001) (Figure 1). Furthermore, all participants presenting with 4 to 10 joints progressed, 60% of them in the first 2 years (Figure 1).
Using multivariable analysis and adding CCP titre and inflammatory markers to the PD positive joint count, Hazard Ratio for the probability of progression shows a risk 2.97 times higher (p >0.001, CI 1.96-4.49) for the participants who met the 2010 ACR/EULAR criteria for RA replacing the swollen joint score with the PD positive joint count (Figure 2).

Conclusion:

1. All of the participants with 4 to 10 joints with a Power Doppler Signal progressed to IA (mainly RA), 60% of them in the first 2 years.
2. The predictive value for progression to IA of ultrasound scans is not improved by the addition of CCP titres and inflammatory markers (when included in the 2010 ACR/EULAR criteria for RA using Power Doppler positive joint count in patient without clinical synovitis).

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/in-ccp-positive-at-risk-of-rheumatoid-arthritis-individuals-the-presence-of-sub-clinical-synovitis-in-4-10joints-universally-results-in-clinical-synovitis/