AB1201 Ultrasonography power doppler(PDUS) in early arthritis. does 44 joint count predicte more accuretly the development of ra than other ultrasound counts?
Authors: L. Mayordomo, C. Almeida, M.C. Jurado, M.L. Velloso, P. González-Moreno, J.L. Marenco
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Early rheumatoid arthritis is a diagnostic challenge for the rheumatologist since early treatment may be crucial for reaching remission and low rate of structural damage. Previous correlation studies between different ultrasonographic (US) scores suggested that few joint examination may be equivalent to more comprehensive ones about the inflammatory activity in stablished rheumatoid artritis. <h3>Objectives</h3> To determine if the presence of basal power doppler US signal in patientes with early artritis by three different US joint counts (12, 28 or 44 joint based) may be equally useful in order to establish the risk of final diagnosis of rheumatoid arthritis (RA) according ACR criteria 1987 at a year of follow up. <h3>Methods</h3> We studied the presence of US Power Doppler (PD) signal on 28 joints (shoulders, elbows, wrists, MCPs, PIPs, knees), 44 joints (28 joints and in addition hips, ankles, tarsus and MTP joints) and in 12 joints (elbows, MCFs 2 and 3, wrists, knees and ankles), with a mid-range equipment GE L5 in 70 pacientes with suspected RA. The patients met at least one of the following inclusion criteria: a) Swelling in 2 or more joints b) pain in MCPs, MTPs and/or the wrists c) morning stiffness of more than 30 min with <i>&lt;</i>12 months of duration of the symptoms and no previous steroid nor DMARDs treatment. At one year of follow-up was established whether patients met <sup>ACR 1987</sup> classification criteria for RA or not. PD signal was scored 0–3, and PD score sum index (IPD) was the total sum of scores in each joint for 44, 28 and 12 joint counts. Correlations between 44, 28 and 12 joint US IPDs were studied as well. Statistical study: Chi-square, Fisher exact test, p univariant, Odds Ratio, Spearman correlation. <h3>Results</h3> The presence of basal power doppler signal in ≥1 joint of 44 (PD44) is associated to RA diagnosis at 12 months by ACR 1987 criteria, p=0.003, OR=5,43<sup>1,71–17,24</sup> but the presence of ≥1 joint with power doppler signal of 28 joints (PD28) did not (p=0.051). The presence ≥1 joint with basal power doppler signal of 12 joints (PD12) was associated to RA diagnosis at 12 months with OR 3,11<sup>1–12–8,6</sup> p=0026 as well, so may predict development of RA. However, we missed 6/44 (14%) of patients that were not diagnosed of RA when we evaluate only 12 joints. We found high correlations between IPD44 and IPD28 (0.845), IPD44 and IPD12 (0.807) and between IPD28 and IPD12 sum scores (0.913). <h3>Conclusions</h3> The presence of at least one joint with power doppler signal of 44 joints (PD44) on baseline visit may help to predict the RA diagnosis at 12 months of follow up according <sup>ACR 1987</sup> criteria in patients with early RA, but PD28 did not. PD12 reduced joint count may help to predict RA as well but missed 14% of RA patients. Odds ratio rendered better information for different PD joint count about early identification of RA, whereas correlations were high between all different US joint scores. Further studies are required to decide the best US joint set for early identification of patients with early rheumatoid arthritis, but inclusion of ankle/foot joints may be important. <h3>Disclosure of Interest</h3> None declared