Incidence of fractures after cardiac and lung transplantation: a single center experience

Optimized surveillance frequency for low bone mineral density (BMD) screening using dual-energy X-ray absorptiometry (DXA) in patients after lung transplant

BACKGROUND

Approximately 2,700 lung transplants are performed annually in the United States. These patients are at increased risk of developing low bone mineral density (BMD) (osteopenia/osteoporosis) and subsequent fractures. Dual-energy X-ray absorptiometry (DXA) is the most common method used for screening for low BMD; however, the optimal surveillance frequency for low BMD using DXA is unknown.

METHODS

We evaluated the change in femoral neck, total femur, L1, L2, L3, and L4 BMD after lung transplant in a retrospective cohort of 259 patients (69.9% male) who were followed with serial DXA scans for a median of 725 (interquartile range [361-1,116]) days after transplant. Generalized linear mixed-effects models adjusting for sex, time, time-squared, baseline osteopenia/osteoporosis, active rejection, and their interaction terms were used to model the rate of change of BMD at each site. The final multivariable models for the femoral neck, L1, and L4 BMD measurements had random slopes and intercepts, and the models for the total hip, L2, and L3 measurements had random slopes.

RESULTS

Sixty-five percent of the patients undergoing lung transplants had osteopenia or osteoporosis before transplant. Men exhibited higher baseline BMD levels compared to women at all sites (p < 0.001 for all). After the transplant, the greatest rate of BMD decrease was at the femoral neck. Although patients with low BMD had significantly lower baseline BMDs (p < 0.001 for all), they experienced a slower rate of BMD decrease at all sites compared to patients with normal BMD at baseline (p < 0.001 for all). All patients received corticosteroids. Patients with low BMD at baseline had significantly higher odds of receiving bisphosphonate therapy (odds ratio = 3.95, 95% confidence interval [CI] [1.44, 13.51], p = 0.003). We estimated that a significant change in the femoral neck BMD would be expected to occur within 409 days (95% CI [131, 708]) and again at 867 days (95% CI [551, 1,216]) after lung transplant.

CONCLUSIONS

Patients undergoing lung transplant should be screened annually with DXA for the first 2 years after transplant, consistent with the current International Society for Heart and Lung Transplantation guidelines.

Increased risk of mortality in lung transplant patients with fragility fractures

Osteoporosis and fragility fractures are frequent complications of lung transplantation patients. Among 131 patients included, 35 (26.5%) patients had a diagnosis of fractures after transplantation. Low bone mineral density was associated with fractures. Fractures post transplantation were identified as an independent risk factor for overall mortality.

INTRODUCTION

The prevalence of osteoporosis among lung transplant candidates has been estimated at 31% to 46%, and significant bone loss occurs after lung transplantation, predominantly in the first year, with increased risk of incident fractures. This study aimed to evaluate the prevalence of fragility fractures in a population of lung transplant recipients and the associated risk factors as well as mortality after a fragility fracture.

PATIENTS AND METHODS

This was a cross-sectional monocentric study that included patients with lung transplantation occurring < 10 years and > 1 year who were undergoing lung transplantation monitoring. All patients underwent bone mineral density evaluation by dual-energy X-ray absorptiometry and radiography to establish the presence of vertebral fractures. Mortality was assessed 2 years after the last inclusion.

RESULTS

We included 131 patients (82 men, 62.6%), with mean age 56.8 ± 10.8 years. The mean time from lung transplantation to inclusion was 3.5 ± 3.5 years. Overall, 35 (26.5%) patients had a diagnosis of fractures after transplantation; 67 fractures were confirmed (average of 2 per patient), including 48 (71.6%) vertebral fractures. Odds of low bone mineral density at the femoral neck, total hip and spine was associated with fracture: odds ratio 0.007 [0.0002-0.3], 0.001 [0.0002-0.05], and 0.03 [0.001-0.6], respectively. Fracture post transplantation was significantly associated with death (hazard ratio 2.32 [1.01-5.33]).

CONCLUSION

This study confirmed a high prevalence of vertebral fracture in lung transplant patients. Fracture after lung transplant was associated with mortality. Bone fragility needs more attention to reduce the fracture risk.

Lung transplantation and bone health: A narrative review

Bone health after lung transplantation has not been comprehensively reviewed in over 2 decades. This narrative review summarizes the available literature on bone health in the context of lung transplantation, including epidemiology, presentation, and postoperative management. Osteoporosis is reported in approximately 30% to 50% of lung transplant candidates, largely due to disease-related impact on bone and lifestyle, and corticosteroid-related effects during end-stage lung disease (interstitial lung diseases, chronic obstructive pulmonary disease, and historically cystic fibrosis). After lung transplantation, many patients experience steroid-induced bone loss, followed by stabilization or recovery to baseline levels with pharmacologic management. Although evidence on fracture incidence is limited, fracture risk appears to increase in the year following transplantation, with common fracture sites including the vertebrae and the ribs. Vertebral and rib fractures restrict chest expansion and affect lung function, underscoring the importance of fracture prevention in lung transplant recipients. There is limited evidence on the pharmacologic management of osteoporosis after lung transplantation. Existing randomized controlled trials have focused on parenteral bisphosphonates and calcitriol but have been underpowered to evaluate their effect on fracture outcomes. Resistance training, particularly in conjunction with antiresorptive therapy, has also been shown to improve bone health when initiated 2 months after transplantation. No studies to date have documented the effectiveness of denosumab in lung transplant recipients; more studies on pharmacotherapy are warranted to elucidate optimal medical management. Considering the high osteoporosis prevalence and fracture risk in lung transplant populations, the development of formal guidance is warranted to promote improved management after transplantation.

Bone Loss after Solid Organ Transplantation: A Review of Organ-Specific Considerations

This review article investigates solid organ transplantation-induced osteoporosis, a critical yet often overlooked issue, emphasizing its significance in post-transplant care. The initial sections provide a comprehensive understanding of the prevalence and multifactorial pathogenesis of transplantation osteoporosis, including factors such as deteriorating post-transplantation health, hormonal changes, and the impact of immunosuppressive medications. Furthermore, the review is dedicated to organ-specific considerations in transplantation osteoporosis, with separate analyses for kidney, liver, heart, and lung transplantations. Each section elucidates the unique challenges and management strategies pertinent to transplantation osteoporosis in relation to each organ type, highlighting the necessity of an organ-specific approach to fully understand the diverse manifestations and implications of transplantation osteoporosis. This review underscores the importance of this topic in transplant medicine, aiming to enhance awareness and knowledge among clinicians and researchers. By comprehensively examining transplantation osteoporosis, this study contributes to the development of improved management and care strategies, ultimately leading to improved patient outcomes in this vulnerable group. This detailed review serves as an essential resource for those involved in the complex multidisciplinary care of transplant recipients.

High risk of osteoporosis and fracture following solid organ transplantation: a population-based study

BACKGROUND

Osteoporosis and fractures increase morbidity and mortality rates after solid organ transplantation (SOT), but few studies have analyzed the risk of osteoporosis and related fractures after SOT. In this retrospective cohort study, we investigated the risk of osteoporosis and fractures in different SOT recipients.

METHODS

This study was a retrospective cohort study using a nationally representative database in Taiwan. We collected the data of SOT recipients and used the propensity score matching method to obtain a comparison cohort. To reduce bias, we excluded patients who had been diagnosed with osteoporosis or fracture before inclusion. All participants were followed up until the date of diagnosis as having a pathological fracture, death, or the end of 2018, whichever occurred first. The Cox proportional hazards model was used to investigate the risk of osteoporosis and pathological fracture in SOT recipients.

RESULTS

After adjustment for the aforementioned variables, SOT recipients were observed to have a higher risk of osteoporosis (hazard ratio (HR) = 1.46, 95% confidence interval (CI): 1.29-1.65) and fracture (HR: 1.19, 95% CI: 1.01-1.39) than the general individuals. Among the different SOT recipients, the highest risk of fractures was noted in heart or lung transplant recipients, with a HR of 4.62 (95% CI: 2.05-10.44). Among the age groups, patients aged >61 years had the highest HRs for osteoporosis (HR: 11.51; 95% CI, 9.10-14.56) and fracture (HR: 11.75, 95% CI: 8.97-15.40).

CONCLUSION

SOT recipients had a higher risk of osteoporosis and related fractures than the general population, with the highest risks observed in patients receiving heart or lung transplants, older patients, and patients with CCI scores of >3.

Bone Disease in Long-Term Lung Transplant Survivors

Background: During the first two years after lung transplantation (LTx), the incidence of fragility fractures (FX) is estimated to be 15–50% and it is lower in patients with cystic fibrosis (CF) as compared with other end-stage lung diseases (nCF). The aim of our study is to compare the skeletal outcomes, after the first 2 years post-LTx, in long-term survivors with CF and nCF. Materials and Methods: We evaluated the FX rate, the changes in bone mineral density (BMD) and trabecular bone score (TBS) in 68 patients (38 CF and 30 nCF) who underwent LTx in our center and with a follow-up after LTx longer than 5 years (7.3 ± 2.0 years). Results: After the second year post-LTx: (i) the FX rate was lower than during the first two years post-LTx (4.4 vs. 20.6%, p = 0.004), with no difference between CF and nCF patients (5.3 vs. 3.3%, p = 0.589); (ii) BMD at lumbar spine, femoral neck and total hip remained stable (−1.6 ± 1.0 vs. −1.4 ± 1.1, p = 0.431, −1.8 ± 0.9 vs. −1.9 ± 0.9, p = 0.683, −1.5 ± 0.9 vs. −1.4 ± 0.9, p = 0.678, respectively) as well as TBS (1.200 ± 0.124 vs. 1.199 ± 0.205, p = 0.166). Conclusions: After the second year post-LTx, the skeletal complications become less frequent and have similar incidence in patients with CF and nCF.

Impact of bone-active drugs and underlying disease on bone health after lung transplantation: A longitudinal study

INTRODUCTION

the effect of bone-active drugs on the risk of fragility fractures (Fx), bone mineral density (BMD) and trabecular bone score (TBS) changes in patients receiving lung transplantation (LTx) is largely unknown. This study assessed the bone-active drugs effect in patients undergoing LTx both with (CF) and without (nCF) cystic-fibrosis.

METHODS

We evaluated incident Fx, both clinical and morphometric vertebral Fx by spinal X-ray, BMD and trabecular bone score (TBS) in 117 patients (CF=50, nCF n = 67) before and 24-months after LTx. A bone-active therapy was proposed to all LTx candidates.

RESULTS

83.8% of patients started a bone-active drug. Lumbar-spine (LS) T-score improved significantly only in treated patients (-1.4 ± 1.0 vs -2.0±1.0, p = 0.0001), whereas femur BMD and TBS remained stable in treated and not treated subjects. The rate of incident Fx was 15.3%, with no difference between treated and not treated patients. After LTx, LS T-score improved significantly only in nCF group (-1.3 ± 1.0 vs -1.8 ± 1.1, p = 0.0001), while femur remained stable in both nCF and CF groups. Patients with CF showed a significant Z-TBS increase (-3.6 ± 1.7 vs -3.0 ± 1.7, p = 0.019) and a lower Fx incidence as compared with nCF patients (4.1% vs 24.2%, p  =0.003). Incident Fx were associated with nCF diagnosis (OR 7.300, CI95% 1.385-38.461, p = 0.019) regardless of prevalent Fx, previous glucocorticoid therapy and bone-active therapy introduced at least 6 months before LTx.

CONCLUSIONS

A prompt medical intervention helps in preventing BMD loss after LTx. As compared with nCF patients, CF patients show a TBS increase and a lower Fx risk after LTx.

Factors associated with degraded trabecular bone score in heart transplant recipients

Trabecular bone score (TBS) is a textural index that provides indirect evaluation of trabecular microarchitecture. It improves fracture risk assessment in several high-risk populations. We aimed to evaluate the role of TBS assessment in heart transplant recipients (HTR). In a cross-sectional study with 87 HTR (69 males and 18 females), we assessed TBS and evaluated potential associations between TBS and factors related to increased fracture risk. We also evaluated the correlations between the presence of vertebral fractures (VF) and degraded TBS. We confirmed degraded TBS in the majority of HTR. 27.6% of HTR had partially degraded, 27.6% had degraded TBS. HTR with degraded TBS were older, had higher body mass index, lower bone mineral density (BMD), and T-score. As opposed to stable BMD over different time points, TBS significantly differed among different post-transplant time periods. TBS did not correlate with current methylprednisolone or past zoledronic acid treatment, presence of hypogonadism or diabetes. TBS did not have additional value over BMD in predicting the presence of VF. Most fractures occurred in patients with osteopenia and in patients with partly degraded TBS. Studies with longitudinal designs and larger sample sizes are warranted to further assess the potential role of TBS in HRT.

Timing of Osteoporotic Vertebral Fractures in Lung and Heart Transplantation: A Longitudinal Study

Bone loss and bone fractures are common complications after organ transplantation. Many factors contribute to the pathogenesis of transplant osteoporosis, such as bone disease preceding transplantation, immunosuppressive medications, and nutritional and lifestyle factors. This study aimed to assess the incidence of vertebral fractures before and after lung and heart transplantation. This longitudinal study analyzed 213 electronic medical records of patients who underwent lung transplantation (n = 128) and heart transplantation (n = 85) at Siena University Medical Center between January 2000 and December 2018. In lung and heart transplant recipients, the bone mineral density in the femoral sub-regions show a significant decrease at post-transplantation and at follow up visits. In both lung and heart recipients, we found an increase in the fracture incidence in the first period after transplantation (19.5% vs. 50.4% in lung recipients; 9.6% vs. 25.7% in heart recipients). Moreover, in lung recipients, vertebral fractures were predicted primarily by age, BMD at the femur, and any history of fracture. In heart recipients, vertebral fractures were predicted only by history of fracture. Our study supports the recommendations for pre-transplant osteoporosis screening in patients undergoing lung transplants, and in the first period after transplantation in heart transplant recipients.

Endocrine disorders after heart transplantation: national cohort study

BACKGROUND

Endocrine disorders in patients after heart transplantation (HT) remain understudied. We aimed to assess endocrine profiles and management of HT recipients in the early post- transplant period.

METHODS

We conducted a retrospective cohort study on 123 consecutive HT recipients in the Advanced Heart Failure and Transplantation Programme between 2009 and 2018. All recipients had per-protocol endocrine follow-up within the first postoperative year. The median time to first post-transplant endocrine follow-up was 3 months (IQR 2-4). We assessed the incidence of vitamin D deficiency, bone mineral density, history of low energy fractures, hypogonadism in male recipients, posttransplant diabetes mellitus, and thyroid and parathyroid function.

RESULTS

We enrolled 22 women and 101 men of median age 57 years (IQR 50-63). Post-transplant diabetes mellitus developed in 14 patients (11.4%). 18 of 25 patients (14.6%) with preexisting type 2 diabetes mellitus required intensification of antidiabetic therapy. 38 male patients (40.4%) had hypogonadism. 5 patients (4.6%) were hypothyroid and 10 (9.3%) latent hyperthyroid. Secondary hyperparathyroidism was present in 19 (17.3%), 25-hydroxyvitamin D deficiency in 64 (54.7%) of patients. Osteoporosis was present in 26 (21.1%), osteopenia in 59 (48.0%) patients. 47 vertebral fractures, 3 hip and 1 humerus fractures occurred in 21 patients. Most of the patients had coincidence of two or three disorders, while less than 5% did not have any endocrine irregularities. All patients received calcium and vitamin D supplements. Forty-six patients (37.4%) were treated with zoledronic acid, 12 (9.8%) with oral bisphosphonates. Two patients were treated with teriparatide.

CONCLUSIONS

The prevalence of multiple endocrine disorders early after heart transplantation is high. Assessment and management of increased fracture risk and all other potentially affected endocrine axes should be considered as a standard of care in this early period.

Chronic Obstructive Pulmonary Disease and the Optimal Timing of Lung Transplantation

Chronic obstructive pulmonary disease (COPD) accounts for the largest proportion of respiratory deaths worldwide and was historically the leading indication for lung transplantation. The success of lung transplantation procedures is measured as survival benefit, calculated as survival with transplantation minus predicted survival without transplantation. In chronic obstructive pulmonary disease, it is difficult to show a clear and consistent survival benefit. Increasing knowledge of the risk factors, phenotypical heterogeneity, systemic manifestations, and their management helps improve our ability to select candidates and list those that will benefit the most from the procedure.

Bone involvement in young adults with cystic fibrosis awaiting lung transplantation for end-stage respiratory failure

Patients with cystic fibrosis awaiting lung transplantation for end-stage respiratory failure have high prevalence of reduced bone mineral density and fragility fracture. Suboptimal 25-hydroxyvitamin D levels could significantly contribute to the development of cystic fibrosis-related bone disease.

INTRODUCTION

The assessment of the prevalence of cystic fibrosis-related bone disease (CFBD) and its associated risk factors in young adults with cystic fibrosis (CF) awaiting lung transplantation for end-stage respiratory failure.

METHODS

Clinical characteristics, bone mineral density (BMD), the parameters of calcium metabolism, including vitamin D (25OHVitD) levels, and the presence of fragility fractures were evaluated in 42 CF patients (24 females, age 34.0 ± 8.4 years) consecutively referred as lung transplant candidates.

RESULTS

Mean 25OHVitD levels (54.9 ± 26.2 nmol/L) were below the reference range and hypovitaminosis D (25OHVitD < 75 nmol/L) was found in 34 patients (81%) and daily calcium intakes (median 550 mg/day) were lower than recommended. A BMD below the expected range for age (Z-score of - 2.0 or lower) and at least one prevalent fragility fracture were found in 22 patients (52.4%) and 18 patients (45.2%), respectively. The coexistence of low BMD and the presence of fracture was observed in 13 patients (31.0%). In these patients, the prevalence of nephrolithiasis was higher than in the remaining ones (p = 0.046). The presence of kidney stones was associated with a worse bone status and with severe vitamin D deficiency. In the whole sample, femoral BMD Z-scores were directly correlated with albumin-adjusted calcium (p < 0.05) and 25OHVitD levels (p < 0.01).

CONCLUSIONS

Despite the improvement of CF care, CFBD is still highly prevalent in young adults awaiting lung transplantation for end-stage CF. Suboptimal 25OHVitD levels could significantly contribute to the development of CFBD. The presence of nephrolithiasis could be an additional warning about the need for a careful evaluation of bone health in CF patients.

Current Status of Research on Osteoporosis after Solid Organ Transplantation: Pathogenesis and Management

Improved survival following organ transplantation has brought to the forefront some long-term complications, among which osteoporosis and associated fractures are the major ones that adversely affect the quality of life in recipients. The pathogenesis of osteoporosis in transplant recipients is complex and multifactorial which may be related to increased bone resorption, decreased bone formation, or both. Studies have shown that the preexisting underlying metabolic bone disorders and the use of immunosuppressive agents are the major risk factors for osteoporosis and fractures after organ transplantation. And rapid bone loss usually occurs in the first 6–12 months with a significant increase in fracture risk. This paper will provide an updated review on the possible pathogenesis of posttransplant osteoporosis and fractures, the natural history, and the current prevention and treatment strategies concerning different types of organ transplantation.

Lung transplantation in chronic obstructive pulmonary disease: patient selection and special considerations

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality and morbidity. Lung transplantation is one of the few treatments available for end-stage COPD with the potential to improve survival and quality of life. The selection of candidates and timing of listing present challenges, as COPD tends to progress fairly slowly, and survival after lung transplantation remains limited. Though the natural course of COPD is difficult to predict, the use of assessments of functional status and multivariable indices such as the BODE index can help identify which patients with COPD are at increased risk for mortality, and hence which are more likely to benefit from lung transplantation. Patients with COPD can undergo either single or bilateral lung transplantation. Although many studies suggest better long-term survival with bilateral lung transplant, especially in younger patients, this continues to be debated, and definitive recommendations about this cannot be made. Patients may be more susceptible to particular complications of transplant for COPD, including native lung hyperinflation, and development of lung cancer.