Serum (OPG) levels and their relationship with the activity of rheumatoid arthritis in newly diagnosed Syrian patients

Abstract

Background & Aim: Rheumatoid arthritis (RA) is a chronic inflammatory disease, of which osteoporosis and articular malformations are the most important complications, the RANKL/OPG pathway plays a prominent role in activating osteoclasts. Our study aimed to evaluate the serum osteoprotegerin (OPG) levels, and its relationship with disease activity in a group of rheumatoid arthritis patients.

materials and methods: The study included 88 participants divided into two groups ((RA patients group included 58 patients (47 females, 11 males), and healthy controls group included 30 individuals (7 males, 23 females)). They were diagnosed based on the criteria of ACR/ EULAR 2010. Serum OPG levels were measured by enzyme-linked immunoassay method Disease activity was assessed according to Disease Activity Score28 (DAS28).

Results: Our results showed an increase in the serum OPG levels in the group of RA patients in comparison with the healthy ones, with a mean of serum concentration respectively (51.76 ± 18.59 pg/ml, 35.67 ± 3.13 pg/ml, P = 0.000). Also the serum OPG levels were higher in the group of RA patients with ACPA antibodies positive compared to the group of ACPA negative RA patients (52.33 ± 18.51, 35 ± 11.2 pg/ml, P = 0.001) and in the group of patients with joint deformities compared to the group of patients without these deformities (60.03 ± 23.2, 45.73 ± 12.1 pg/ml , P = 0.001). Our study showed that there was no statistically significant difference in OPG levels between the two groups of RF positive or negative RA patients, where the value of (P = 0.959). On the other hand we did not find a significant correlation between serum OPG levels with each of the disease activity score DAS28, ACPA, RF, ESR, CRP. At a value of 39.91pg/ml OPG we obtained a sensitivity of 77.5% and a specificity of 100% to differentiate between rheumatoid arthritis patients and healthy ones

Conclusion: High serum levels of OPG may reflect a change in the level of bone metabolism in patients with RA, and is an important new prognostic marker that can be added but their levels do not correlate with the activity of rheumatoid arthritis.