Risk factors for bone mineral density changes in patients with rheumatoid arthritis and fracture risk assessment / 北京大学学报(医学版)

ABSTRACT

Objective:To verify the fracture risk assessment tool ( FRAX) to estimate the probability of osteoporotic fracture in patients with rheumatoid arthritis ( RA ) with or without bone mineral density (BMD), and identify associated risk factors of osteoporosis .Methods: In the study, 200 patients with rheumatoid arthritis aged more than 40 years in Peking University First Hospital from Dec .2009 to Dec. 2012 were recruited.Clinical information was obtained from a questionnaire of their case history and medical records.FRAX tool was administered.Their lumber spine and left femoral BMD were determined by dual energy X ray absorptiometry.The gender, age, disease duration, menopause status, body mass index ( BMI) and accumulative dose of glucocorticoid were obtained in retrospect .Correlation analysis was conducted between the BMD and clinical information .Results:The study population ( female, 77.5%) had a mean age of 59.4 years, in which 10 (13%) patients showed a normal BMD, 67 (87%) were osteopenia or osteoporosis , while 32 patients (16%) had fragile fracture.Compared with the patients with normal BMD, the subjects with low BMD had significantly older age , longer period for corticoids usage , higher day dose and accumulated dose of corticoids .The 10-year fracture risk of sustai-ning major osteoporotic fractures and hip fracture was higher .No significant difference was observed be-tween the 10-year fracture risks calculated with BMD and without BMD .The values of the different area under the receiver operating characteristic ( ROC) curve ( AUC) for major and hip fractures calculated in three wayswithout BMD, with the femoral neck BMD, and with T-score.The best result was for FRAX tool for hip fracture with the T-score ( AUC 0 .899 ) .A stepwise multivariate linear regression model was constructed to explore the relationship between the different clinical factors studied and a low BMD . Three statistically significant variables for lumber BMD were pain on visual assessment scale ( VAS ) (P=0.02), fracture history (P=0.003) and a higher steroid accumulated dose (P=0.008).Three statistically significant variables for left hip BMD were age (P<0.001), fracture history (P=0.05) and lower BMI ( P=0.03) .Conclusion:Low BMD is a common complication in RA patients .Risk factors for major fracture and hip fracture are increased .There is a positive correlation between FRAX calculated with and without BMD or T score .FRAX with the femoral neck T score or BMD presents a discriminatory capacity better than FRAX without BMD , according to the AUC ROC .