FRI0592 Serum Calprotectin is Associated with Ultrasound-Determined Active Synovitis in Patients with Rheumatoid Arthritis

BackgroundCalprotectin (S100A8/9, MRP8/14) is a promising circulating biomarker reflecting disease activity in patients with rheumatoid arthritis (RA). In two small previous studies in RA patients1,2, serum calprotectin correlated with ultrasound synovial inflammation.ObjectivesTo investigate associations between serum calprotectin, clinical and ultrasound-determined disease activity in a larger cohort of RA patients in a cross-sectional study.MethodsA total of 167 patients with RA (134 females) were enrolled in this study. All patients underwent clinical assessment (SJC, TJC, DAS28-ESR) and ultrasound examination according to the US-7 score3 to assess synovitis by gray-scale (GS) and power Doppler (PD) using semiquantitative grading (0-3). Serum calprotecin was measured by ELISA. Associations between serum calprotectin, C-reactive protein (CRP) and clinical as well as ultrasound findings were explored using Spearman's correlation coefficient. A multiple regression analysis was used to determine the predictive value of calprotectin (mg/l), CRP (mg/l) and DAS28 for GS and PD synovitis score.ResultsSerum calprotectin significantly correlated with DAS28 (r=0.357, p