Discriminative ability of trabecular bone score over bone mineral density for vertebral and fragility fracture in patients treated with long-term and low-dose glucocorticoid.

Abstract

To evaluate the ability of the trabecular bone score (TBS) to discriminate vertebral fracture (VF) and fragility fracture (FF) in patients with chronic inflammatory rheumatic diseases on long-term and low-dose glucocorticoid (GC) treatment and those without exposure to GC. This study assessed TBS and bone mineral density (BMD) in chronic GC users, defined as ≥2.5mg/d of prednisone for >3months (n=89, mean age: 62.5±11years), and in controls (n=59, mean age: 60.3±9.6years). Osteoporosis risk factors, radiographs of the thoracolumbar spine, non-VF history, osteoporosis drugs, and current/cumulative GC doses were collected. Patients were classified as high (TBS <1.23), intermediate (1.23-1.31), or low risk (>1.31), according to the fracture risk based on a recent meta-analysis. The mean current dose and duration of GC treatment were 3.9±1.9mg/d and 3.9±4.2years, respectively. The prevalence of VF was significantly higher in chronic GC users than in controls (20.2% vs 5.1%, P=.010), although the prevalence of non-VF was similar (11.2% vs 5.1%). The GC group had significantly lower L1-L4 TBS and femur total BMD than did the controls (all with P<.01) without significantly different lumbar BMD. TBS (<1.31) showed a higher sensitivity for patients with VF and FF (83.3% and 81.8%, respectively) than with densitometric osteoporosis in the GC group (61.1% and 59.1%, respectively). Using the receiver operating characteristic curve, TBS <1.31 showed better diagnostic accuracy than TBS <1.23 and BMD in chronic GC users. TBS is more sensitive than BMD in detecting VF and FF in chronic GC users, even at a lower dose.