Study objective: Osteoporosis is a well-recognized complication of lung transplantation that may significantly impair the quality of life of transplant recipients. We performed a prospective study of bone mineral density (BMD) before and after transplantation to determine the degree of bone mass loss associated with lung transplantation Patients and design: We conducted a prospective study of BMD in 28 patients with various end-stage respiratory diseases pretransplantation and 6 to 12 months posttransplantation. The BMD of the lumbar spine (LS) and femoral neck (FN) were measured. All 28 patients were treated only with vitamin D and calcium supplementation posttransplant. The primary endpoint was the percentage change in BMD. The secondary endpoint was the incidence of fractures posttransplant. A univariate analysis was conducted to determine the various risk factors associated with bone mass loss pretransplant and posttransplant.
Results: Prior to transplantation, moderate to severe bone disease was evident. The mean (+/- SD) pretransplant T score (the number of SDs from the peak bone mass) and Z score (the number of SDs from the age-matched mean) for the LS were -1.72 +/- 1.37 and -1.44 +/- 1.31, respectively. The mean pretransplant T score and Z score for the FN were -2.65 +/- 1.01 and -1.5 +/- 1.43, respectively. Within 6 to 12 months posttransplant, the mean BMD for the LS decreased by 4.76% (p < 0.001), while the mean BMD for the FN decreased by 5.3% (p < 0.001). Five of the 28 patients (18%) suffered osteoporotic fractures posttransplant, while no fractures were documented pretransplant. The cumulative steroid dose posttransplant was associated with a drop in BMD for the LS and FN (r = 0.39, p = 0.039 and r = 0.63, p < 0.001, respectively), while a negative association was found between cumulative steroid use pretransplant and baseline LS and FN T scores (r = -0.4, p = 0. 02 and r = -0.43, p = 0.023, respectively).
Conclusion: Within 6 to 12 months after lung transplantation, there is a significant decrease in BMD at both the LS and FN levels (approximately 5%) despite vitamin D and calcium supplementation. This drop in BMD is associated with a relatively high incidence of osteoporotic fractures posttransplant.