Osteoporosis in Lung Transplantation Candidates: Association With 6-minute Walking Test and Body Mass Index

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.

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.

Analytic Morphomics Are Related to Outcomes After Lung Volume Reduction Surgery

:Lung volume reduction surgery continues to have a high morbidity despite National Emphysema Treatment Trial selection criteria. This study evaluated the association between analytic morphomics on chest computed tomography scans and outcomes after lung volume reduction surgery. In a retrospective review of 85 lung volume reduction surgery patients from 1998-2013, dorsal muscle group area, subcutaneous and visceral fat area, and bone mineral density were assessed using analytic morphomics. Lung density was divided into five levels of increasing density (Lung density 1, emphysema; 2, normal lung; 4-5, scarring). Outcomes including survival, hospital length of stay, readmission at 30 days, and pulmonary complications were analyzed using univariate and multivariable techniques. Pulmonary complications developed in 27.1% (23/85). Mortality at 90 days was 9.4% (8/85). On multivariable analysis, lower bone mineral density (Odds ratio 0.61; 95% confidence interval 0.39-0.95) was associated with decreased survival, longer length of stay (0.83; 0.77-0.89), and readmissions (0.39; 0.15-1.00). Higher lung density 5:lung density 2 volume (1.84; 1.05-3.23), possibly due to scarring, was associated with pulmonary complications and longer length of stay (1.32; 1.23-1.41) while lower subcutaneous fat area:height was associated with readmissions which may reflect decreased metabolic reserve (0.35; 0.13-0.93). Patients with signs of frailty including lower bone mineral density may be at increased risk of adverse outcomes including decreased survival after lung volume reduction surgery. The results of this hypothesis-generating study will need to be confirmed in larger, multicenter trials to determine whether analytic morphomics can improve risk stratification and patient selection.

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.