Background: Patients with pyogenic vertebral osteomyelitis (PVO) are expected to have increased risk of bone loss. Therefore, early bisphosphonate therapy would be clinically effective for PVO patients with osteoporosis.
Methods: A retrospective case review was performed on PVO patients with osteoporosis. PVO patients were divided into three groups: group A (initiation of bisphosphonate within 6 weeks after PVO diagnosis); group B (initiation of bisphosphonate between 6 weeks and 3 months after PVO diagnosis), and group C (no treatment for osteoporosis). Cox proportional hazard model was used to evaluate long-term effectiveness and safety of bisphosphonate in PVO patients, and event of interests included surgical treatment, recurrence of infection, subsequent fracture of adjacent vertebral bodies, and death.
Results: A total of 360 PVO patients with osteoporosis were investigated for the four events of interest. Group A PVO patients had significantly lower hazard ratios for undergoing later (more than 6 weeks after diagnosis) surgery than group C PVO patients (p=0.014 for model 1 and 2) (Figure 1) despite similar occurrences of overall surgery. Significant difference was also observed in the occurrence of subsequent fractures at adjacent vertebral bodies (p=0.001 for model 1 and p=0.002 for model 2), and group A and B PVO patients had significantly lower hazard ratios for subsequent fracture than group C PVO patients (Figure 2). There were no significant differences in the hazard ratios of recurrence and death among the three groups.
Conclusion: Early bisphosphonate treatment in PVO patients with osteoporosis was associated with significantly lower occurrence of subsequent vertebral fracture at adjacent vertebral bodies, and lower occurrence of later surgery.