Supplementary Material for: Evaluation of bone mineral density in lung transplant recipients by chest computed tomography

Introduction: Lung transplantation (LT) recipients are at risk of bone mineral density (BMD) loss. Pre- and post-LT BMD loss has been reported in some cross-sectional studies; however, there are limited studies regarding the serial BMD change in LT recipients. The aim of this study was to investigate the serial BMD changes and the clinical characteristics associated with BMD decline. Methods: This was a single-center, retrospective observational study. BMD was serially measured in thoracic vertebral bodies (Th4, 7, 10) using computed tomography (CT) before and 3 and 12 months after LT. The frequency of osteoporosis and factors associated with pre-LT osteoporosis and post-LT BMD loss were evaluated. The frequency of post-LT compression fracture and its associated factors were also analyzed. Results: This study included 128 adult LT recipients. LT recipients had decreased BMD (151.8 ± 42.2 mg/mL) before LT compared with age-, sex-, and smoking index-matched controls (176.2 ± 35.7 mg/mL). The diagnosis of COPD was associated with pre-LT osteoporosis. LT recipients experience further BMD decline after transplantation, and the percentage of recipients classified as exhibiting osteoporosis increased from 20% at baseline to 43% at 12 months. Recipients who had been taking no or small doses of glucocorticoids before LT had rapid BMD loss after LT. Early bisphosphonate use (within 3 months) after LT attenuated BMD loss and decreased new-onset compression fracture. Conclusion: LT recipients are at high risk for BMD loss and compression fracture after LT. Early bisphosphonate use may decrease BMD loss and compression fracture.

引言：肺移植（Lung Transplantation, LT）受者存在骨矿物质密度（Bone Mineral Density, BMD）丢失的风险。现有部分横断面研究已报道肺移植前后的骨密度丢失情况，但针对肺移植受者骨密度序列变化的相关研究较为匮乏。本研究旨在探讨肺移植受者的骨密度序列变化特征，以及与骨密度下降相关的临床影响因素。
方法：本研究为单中心回顾性观察性研究。于肺移植前、移植后3个月及12个月，采用计算机断层扫描（Computed Tomography, CT）对受者的胸椎椎体（Th4、Th7、Th10）进行骨密度的连续测量。本研究评估了骨质疏松症的患病率，以及与肺移植前骨质疏松症、移植后骨密度丢失相关的影响因素；同时还分析了肺移植后椎体压缩性骨折的患病率及其相关危险因素。
结果：本研究共纳入128名成年肺移植受者。与年龄、性别及吸烟指数匹配的对照组（176.2±35.7 mg/mL）相比，肺移植受者移植前的骨密度水平（151.8±42.2 mg/mL）显著降低。慢性阻塞性肺疾病（Chronic Obstructive Pulmonary Disease, COPD）诊断与肺移植前骨质疏松症存在相关性。肺移植受者在移植后会出现进一步的骨密度丢失，被确诊为骨质疏松症的受者比例从基线时的20%升至12个月时的43%。肺移植前未使用糖皮质激素或仅使用小剂量糖皮质激素的受者，术后骨密度下降速度更快。肺移植后3个月内早期应用双膦酸盐（bisphosphonate）可减轻骨密度丢失，并降低新发椎体压缩性骨折的发生率。
结论：肺移植受者在移植后面临骨密度丢失及椎体压缩性骨折的高风险。术后早期使用双膦酸盐或可减轻骨密度丢失，降低新发椎体压缩性骨折的发生风险。