Clinical Evaluation of the Level and Shape of Vertebral Compression Fractures and Bone Metabolic Markers Between Involutional and Glucocorticoid-Induced Osteoporosis

摘要

Glucocorticoid-induced osteoporosis (GOP) is the most representative kind of secondary osteoporosis. However, little is known about its radiographic feature of vertebral compression fracture (VCF) when compared to that of involutional osteoporosis (IOP). In the present study, the level (T3-L5) and shape of VCFs observed in lateral spine radiographs as well as bone metabolic markers including serum osteocalcin (OC), bone alkaline phosphatase (BAP), urinary deoxypyridinorine (DPD), and N-terminal cross-linked telopeptide of type I collagen (NTX) were evaluated. Subjects were 76 IOP and 24 GOP patients with one or more VCFs. Compared to IOP group, the average age in GOP group was significantly younger (IOP: 70.2 years, GOP: 66.8 years; p=0.0049), the average number of VCF was greater (IOP: 3.0 vertebrae, GOP: 5.7 vertebrae; p=0.0001), and the platy type feature was more frequently observed (p=0.0003). In patients with IOP, most of VCFs were seen in singular or in double in the thoracolumbar junction. With advanced condition, the wedge fracture in the thoracolumbar junction seemed to slowly spread to the adjacent levels. Fish type features increased in the lumbar area and the shape changed from a wedge to a platy type. On the other hand, patients in GOP group, multiple fractures were common at first visit. The rate of wedge and platy type features increased further as the condition advanced. Wedge fractures frequently occurred in the thoracic area and the deformed shape changed from fish to platy type in the lumbar area. Bone metabolic markers showed that only OC, a bone formation marker, was significantly lower in GOP group. In conclusion, there were apparent differences in the number, level and shape of VCF between IOP and GOP groups and the decline of OC level in GOP group indicated the regression of bone formation.