Association of serum osteoprotegerin and osteoprotegerin gene polymorphism with subclinical carotid artery atherosclerosis and disease activity in rheumatoid arthritis patients

To investigate the association of single nucleotide polymorphism (SNP) (rs2073618) of the OPG gene and of serum OPG with subclinical carotid atherosclerosis in RA patients. Eighty RA patients with no previous history of a cardiovascular disease were studied and forty healthy controls were enrolled in the study. Carotid atherosclerosis was evaluated by high-resolution B-mode ultrasound and the carotid intimal medial thickness (CIMT) measured. rs2073618 OPG genotyping was performed by polymerized chain reaction (PCR) and serum OPG concentrations were measured. The high sensitive C reactive protein (hs-CRP), rheumatoid factor (RF) titer and anti-cyclic citrullinated peptide (anti-CCP) were assessed. The disease activity score (DAS28) was evaluated. The patients mean age was54.1 ± 6.2 years, disease duration of 12.5 ± 8.5 years and were 72 females and 8 males. Increased IMT was found in 38 patients, 40 age and sex matched controls were included. Patients with atherosclerosis (n = 38) had longer disease duration, higherDAS28, hs-CRP, RF titer and anti-CCP. The serum OPG levels were higher in patients with atherosclerosis (1106.4 ± 1157.1 ng/l) compared to those without (658.3 ± 151.1 ng/l)(p = 0.001). Serum OPG significantly correlated with disease duration (r = 0.42, p = 0.005), DAS28 (r = 0.53, p = 0.001), hs-CRP (r = 0.41, p = 0.007), anti-CCP (r = 0.47, p = 0.003) and mean CIMT (r = 0.37, p = 0.02). The frequencies of CC, CG and GG genotypes were comparable between those with and without atherosclerosis (39.5%, 50%, 10.4% vs 42.9%, 47.6% and 9.5% respectively). rs2073618 OPG gene may not be associated with subclinical atherosclerosis, although the serum level could be a reliable marker for disease activity and for early detection of carotid artery atherosclerosis in RA.