Serum Levels of , and Ratio in Patients with Ankylosing Spondylitis: A Systematic Review and Meta-analysis.

: To investigate the role of osteoprotegerin (), receptor activator of nuclear factor-kB ligand (), and ratio in the pathogenesis of ankylosing spondylitis (AS). : Studies that compared serum levels of , and / ratio between AS patients and healthy controls were gathered. Pooled standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated by the random-effects model. : Twenty studies containing 1592 AS patients and 1064 healthy controls were included in this meta-analysis. Serum levels of , and ratio in AS patients were significantly higher than that in normal controls (: SMD = 0.401, 95%CI = 0.026-0.777, = 0.036; : SMD = 1.116, 95%CI = 0.510-1.723, < 0.001; ratio: SMD = 0.691, 95%CI = 0.084-1.299, = 0.026, respectively). Subgroup analysis suggested that Asian AS patients and patients with elevated ESR (ESR >20 mm/h) had higher serum levels compared to normal controls. Asian patients, CRP >10 mg/L, ESR >20 mm/h, duration of disease ≤8 years, and BASDAI score >4 points subgroups showed increased levels compared to controls. : Serum levels of , and ratio may be used as potential susceptible biomarkers for AS, but they could be influenced by race, inflammatory factors, and disease activity of AS patients.