AB0301 Serum pyridinoline is associated with radiographic joint erosions in rheumatoid arthritis

Background Pyridinoline (Pyd) is a 3-hydroxypyridinium derivative which is an intermolecular cross-link compound of type I and II collagen.1 It is a marker of bone resorption based on bone biopsy and radioisotope kinetics studies.2In rheumatoid arthritis (RA), destruction of bones may contribute to increased levels of serum Pyd. Objectives The purpose of this study was to compare the serum pyridinoline (Pyd) levels between RA patients and healthy controls and to determine the correlation of serum Pyd levels with radiographic joint erosions. Methods This was a monocentric, cross sectional, case-control study which was conducted from June 2016 to February 2017 at the Universiti Kebangsaan Malaysia Medical Centre (UKMMC). Serum samples were obtained from 48 patients with RA and 48 healthy controls. The enzyme-linked immunosorbent assay (ELISA) method was used for quantitative analysis of serum Pyd. Besides, all the RA patients were assessed for joint damage based on Modified Sharp Score (MSS), disease activity based on the disease activity score in 28-joints (DAS 28) and functional capacity based on Health Assessment Questionnaires Disability Index (HAQ-DI). Results The median serum Pyd levels was much higher among the RA patients (110.20 ng/mL [92.30–120.64]) compared to the controls (98.22 ng/mL [85.54–111.41]); p Conclusions RA patients had significantly higher levels of serum Pyd compared to healthy controls. The serum Pyd levels had significant correlation with radiographic joint erosions which reflected disease damage. References [1] Nemoto R, Nakamura I, Nishijima Y, Shiobara K, Shimizu M, Takehara T, et al. Serum pyridinoline crosslinks as markers of tumour-induced bone resorption. Br J Urol. 1997;80:274–80. [2] Plant MJ, Williams AL, O’Sullivan MM, Lewis PA, Coles EC, Jessop JD. Relationship between time-integrated C-reactive protein levels and radiologic progression in patients with rheumatoid arthritis. Arthritis Rheum2000;43:1473–7. Acknowledgements The authors would like to thank the Research Committee of UKMMC for funding this research. Disclosure of Interest None declared