Association between serum RANKL/OPG ratio and osteoporotic fracture in patients with rheumatoid arthritis / 中华全科医师杂志

ABSTRACT

Objective To investigate the value of serum receptor activator of nuclear factor kappa B ligand (RANKL)/osteoprotegrin (OPG) ratio in osteoporotic fracture (OPF) of patients with rheumatoid arthritis (RA).Methods Three hundred and eighty four RA patients with mean age of (49 ± 14) y (16-82) admitted in the First Affiliated Hospital of Anhui Medical University from 2010 to 2013 and 158 sex-and age-matched healthy subjects were enrolled in the study.OPF was diagnosed by X-ray examination and BMDs of femur and lumbar spine 2-4 (L2-4) were measured by dual energy X-ray absorptiometry.Levels of RANKL and OPG in the peripheral blood of 220 RA patients and 100 normal subjects were detected by ELISA method.Results Eighty-two cases of OPF was diagnosed in 384 RA patients (21.35％),the rate was higher than that in controls (3.80％,6/158,x2 =25.371,P ＜0.01).The peripheral blood levels of RANKL (0.150 ± 0.143 vs.0.101 ± 0.066,t =4.178,P ＜ 0.01),OPG (0.457 ± 0.293 vs.0.359 ±0.216,t=3.347,P=0.001) and ratio of RANKL/OPG (0.41 ±0.35 vs.0.34±0.20,t =2.111,P=0.036) in RA patients were significantly higher than those in control group.In comparison with normal controls,BMDs of all detected regions in RA were decreased significantly (P ＜0.01).The incidence of osteoporosis in RA (121/327,37％) was higher than that in normal controls (22/158,13.92％) (x2 =27.291,P ＜ 0.01).RA patients with OPF had higher age (t =4.377,P ＜ 0.01),longer duration of disease (t =2.612,P =0.009),higher RANKL level (t =3.554,P =0.001),higher RANKL/OPG ratio (t =2.651,P =0.010),higher health assessment questionnaires (HAQ) score (t =2.418,P =0.016),lower serum calcium level (t =2.183,P =0.030),lower hemoglobin level (t =2.125,P =0.036),higher Sharp score in hands X-ray examination (t =2.747,P =0.007),worse X-ray stage (x2 =7.856,P =0.049),higher glucocorticoid utilization rate (x2 =9.066,P =0.003) and higher incidence of osteoporosis (x2 =38.186,P ＜ 0.01),compared with patients without OPF.RA patients taking corticosteroids had higher incidence of osteoporosis (x2 =7.489,P =0.006) and higher incidence of OPF (x2 =9.066,P =0.003).Logistic regression analysis showed that age (OR =1.029,P =0.039,95％ CI1.001-1.057)and the occurrence of osteoporosis (OR =3.159,P =0.001,95％ CI1.562-6.385),RANKL/OPG ratio (OR =3.516,P =0.013,95 ％ CI1.305-9.647) were risk factors for RA patients with OPF.Conclusion A higher incidence of OPF is prevalent in RA patients,and age,osteoporosis,taking glucocorticoids and RANKL/OPG ratio are risk factors for OPF in RA patients.