Aims: Patients with traumatic spinal cord injury (TSCI) have high prevalence of osteoporosis and increased lifetime fracture risk particularly at the hip and knee. Risk factors include extent of lesion (motor-complete) and time since injury. Few studies have explored antiresorptive efficacy in chronic TSCI-related osteoporosis.
Methods: We aimed to assess efficacy of sequential zoledronic acid (ZOL) in preventing BMD loss at the hip in chronic TSCI-related osteoporosis. Retrospective review was conducted of patients with chronic TSCI (duration ≥1-year) managed in osteoporosis clinics at Royal North Shore Hospital between 2013-2023. Eligible patients were those receiving ≥1 ZOL infusion with ≥1 follow-up hip DXA BMD scan.
Results: The cohort (N=23) were predominantly male (74%) with mean (SD) age 46.0±15.0-years. Majority had cervical-level lesions (61%) with motor-complete injuries (65%). Mean interval between TSCI and ZOL was 15.0±11.0-years. BMD values and T-scores were low for total hip (0.593±0.192 g/cm2; -3.0±1.3 SD) and femoral neck (0.537±0.168 g/cm2, -2.7±1.8 SD). Lower limb fragility fractures were prevalent at the hip (n=4), femur (n=2) and tibia (n=1). Patients received median three ZOL infusions over median 4-years follow-up. Total hip BMD showed no difference at 1-year but improved at latest follow-up (+5.0%±8.0%, p=0.016). Femoral neck BMD improved at 1-year (+3.8%±4.3%, p=0.002) and latest follow-up (+6.8%±8.1%, p<0.001). Total hip BMD trended towards greater improvement in patients with motor-incomplete than motor-complete lesions (+7.1%±10.9% vs +3.5%±6.9%, p=0.372). Patients with longer TSCI duration (≥15-years) had more severe osteoporosis (total hip T-score (SD): -3.6±1.1 vs -2.4±1.1, p=0.007) with no observed difference in BMD response.
Conclusion: In this sizeable real-world cohort with chronic TSCI-related osteoporosis, robust gains in hip BMD (~5-6%) were observed with sequential ZOL. Our study is limited by retrospective design, absence of controls or knee BMD assessment. These findings require confirmation in prospective controlled studies to inform chronic TSCI-related osteoporosis management.