Long-term bone mineral density changes and fractures in lung transplant recipients with cystic fibrosis

BackgroundLittle is known about long-term bone mineral density (BMD) changes and fractures in lung transplant recipients with cystic fibrosis (CF). We examined femur and lumbar spine (LS) BMD changes in men and women with CF up to 10 years post-transplant and documented post-transplant fracture prevalence.MethodsRetrospective study of individuals who had undergone a lung transplant (2000–2015) and had a pre-transplant and at least one BMD measurement after transplant. Vertebral fractures were assessed on chest computed tomography scans and other fractures abstracted from medical records.ResultsThe cohort consisted of 131 individuals; 53% males, median age: 28 years interquartile range: 24–35] and 31% having pre-transplant low bone mass. Most recipients were given bisphosphonates after transplant with proportion reaching 94% at 10 years. Up to 10 years post-transplant, men experienced positive or little change in LS BMD, indicating minimal loss from pre-transplant values. In contrast, women displayed negative changes in BMD up to 5 years post-transplant before recovering pre-transplant BMD values by 10 years. Similar patterns were observed at the femur BMD where men demonstrated a lower bone loss and faster recovery towards pre-transplant values than women. After transplant, 88% of recipients maintained their pre-transplant bone status, 3% experienced an improvement, mostly progressing from low bone mass to normal status whereas 9% had a deterioration of their pre-transplant bone status. Twenty-seven recipients suffered fractures in the post-transplant period.ConclusionsThese findings underline that lung recipients with CF remain at risk of skeletal fragility despite prompt initiation of post-transplant anti-osteoporosis therapy.