AB1060 Measuring agreement in the ultrasonographic evaluation of disease activity in rheumatoid arthritis patients. a latin-american multicenter exercise assessing the influence of sonographer experience and expertise

Abstract

Background: Ultrasonography (US) is an important tool in rheumatology practice but it depends on sonographer's experience. Objectives: To evaluate the reliability of US assessment among observers across Latin American using a web tool. Methods: Cross-sectional study. Fifty-one Latin American ultrasonographers took part in a web- based US exercise evaluating images from 20 RA patients. The 4 joints US score was calculated for each patient including bilateral radiocarpal, midcarpal and second metacarpophalangeal joints. PD and GS were graded from 0 to 3. US scores comes as the result of the addition of PD and GS score, being 36 the highest disease activity. Five patients were evaluated twice in order to address intra - rater reliability. The inter and intra-rater reliability was assessed using a two-way random, absolute, individual and average-measures intra-class correlation coefficient (ICC). We stratified sonographers according to experience (defining High experience as: at least 5 years of experience and 80 US assessments/month). Results: A total of 1020 US image assessments were performed. Mean 4-joints US score was 17±8. The ICC was in the excellent range for intra [(individual ICC = 0.945 (IC95% 0.905-0.965); average ICC =0.972 (IC95% 0.950-0.982)] and inter- reader reliability [(individual ICC =0.867 (IC95% 0.786-0.934); average ICC = 0.997 (IC95% 0.995-0.999)]. When comparing high with low experience sonographers, there was no significant differences in intra-class correlation coefficient. However, there was a greater variation between the means among low experience readers (13 to 22) and higher experience sonographers (14-18) (Figure 1). Conclusions: US reliability is related to sonographer expertise and experience.