Lung transplantation (LTx) requires long term immunosuppression with high dose glucocorticoids. At our institution, we have implemented a protocol of regular zoledronic acid (ZA) infusions for all LTx recipients from the time of wait-listing, with the aim of minimising glucocorticoid-induced osteoporosis and fracture. We sought to determine the prevalence of and risk factors for fracture, as well as rates of antiresorptive use and treatment-related adverse events in our patient cohort. Adults who underwent LTx at our institution from 1/1/2012 to 31/12/2018 and survived more than 6 months were included. Patients who moved interstate were excluded, leaving a total of 405 patients (168 female), with median age at LTx of 59 years.
A total of 73 patients (18%) sustained osteoporotic fractures, of whom 38 had fractured prior to LTx, and 51 (13%) developed new osteoporotic fractures post-LTx. The commonest fracture site was vertebral. There was also a high prevalence of non-osteoporotic fractures (n= 78, 19%), involving the ribs (n=49), foot (n=31) and ankle (n=15).
165 patients (41%) received at least 1 dose of ZA prior to LTx, and 346 (85%) received at least 1 dose of ZA post-LTx. Adverse events were uncommon. Atypical femoral fracture occurred in 1 patient (who had received 6 doses of zoledronic acid) and another developed osteonecrosis of the jaw.
Statistically significant risk factors for osteoporotic fracture post-LTx were: osteoporotic fracture pre-LTx, female gender and increasing age. Of note, bisphosphonate use pre-Tx was associated with increased fracture rates, likely representing selection bias. Following LTx, bisphosphonate therapy was not associated with osteoporotic fracture. This may reflect its frequent use.
In summary, although LTx recipients have a high prevalence of osteoporotic fractures, rates of post -LTx fracture may be lower than expected for such a high risk group, possibly as a result of routine intervention.