The Utility of Prophylactic Zoledronic Acid in Patients Undergoing Lung Transplantation - A Retrospective Analysis

Abstract

Purpose Osteoporosis is prevalent among lung transplant candidates and is exacerbated post-transplant by immunosuppressive therapy (glucocorticoids and calcineurin inhibitors). Osteoporotic fractures are a significant source of morbidity. Low bone mineral density (BMD) is a well-recognised surrogate for fracture risk. Intravenous zoledronic acid (ZA) effectively prevents the former and reduces the latter in post-menopausal osteoporosis. Many groups, ours included, prophylactically treat lung transplant recipients with bisphosphonates to prevent BMD reduction and reduce fracture rates. However, no documented national or international consensus exists to date. Our protocol comprises six-monthly ZA infusions from wait-listing, with interval reassessment to guide ongoing treatment. The purpose of our study is to audit the impact of this protocol on BMD and fracture occurrence. Methods A retrospective analysis was performed on all adults receiving a lung transplant from April 2012 to October 2014. 60 of 142 met inclusion criteria, which included a 3-year follow up period post-transplant with BMD assessment 1) within 24 months pre-transplant and 2) 36-60 months post-transplant. Those who received ZA within 6 months of their transplant as per protocol (n=37) were compared to those who did not (n=23). The outcome measures were change in BMD at the lumbar spine and hip (primary), and fracture occurrence (secondary). Results The group treated as per protocol experienced a median change in BMD of 8.11% at the spine and 1.39% at the femur, compared to -1.20% and -2.92%, respectively, in the group not treated as per protocol (p=0.003) (table 1). Our results suggest that prophylactic ZA in the lung transplant cohort is effective in reducing BMD loss and may reduce fracture rates. Conclusion Proven benefit of this protocol may influence clinical practice not only at our centre but may contribute to an international consensus on the best management of bone health in lung transplant patients.