Elevated incidence of fractures in solid-organ transplant recipients on glucocorticoid-sparing immunosuppressive regimens

Postoperative Care and Outcomes in Solid-Organ Transplant Patients Undergoing Lower Extremity Fracture Treatment

OBJECTIVES

To determine the postoperative outcomes in solid-organ transplant (SOT) patients undergoing operative treatment of lower extremity fractures.

METHODS

DESIGN

Retrospective comparative study.

SETTING

Academic Level 1 trauma center.

PATIENT SELECTION CRITERIA

Patients who underwent SOT and operative treatment of lower extremity fracture from 2013 to 2021 were identified, excluding pathologic fractures.

OUTCOME MEASURES AND COMPARISONS

Postoperative complications, length of stay, time to death, 90-day and 1-year readmission rates, readmission causes, discharge location, and immunosuppressive regiments.

RESULTS

Sixty-one patients with an average age of 67 years (range 29-88) were included. The mortality rate was 37.7%. The average follow-up was 15.2 months (range of 2 weeks-10 years). The majority of patients (32.8%) had received a liver transplant, and femoral neck fractures constituted the largest fracture group. The average length of stay was 10 days, with the shortest being 1 day and the longest being 126 days (SD 18). The majority of patients (57.3%) were not discharged home. Only 2 suffered from a postoperative complication requiring another procedure: hardware removal and liner exchange for periprosthetic joint infection, respectively. There was a 27.9% 90-day readmission rate with 2 deaths within that period with the most common being altered mental status (29.4%), genitourinary infections (17.6%), repeat falls (11.8%), and low hemoglobin requiring transfusion (11.8%). The longest average time to death analyzed by transplant type was found among lung transplant patients (1076 days, 62.5% mortality), followed by liver transplant patients (949 days, 35.0% mortality), and then kidney transplant patients (834 days, 38.9% mortality). The shortest time to death was 71 days from index procedure.

CONCLUSIONS

Family members of SOT patients undergoing operative treatment of lower extremity fractures should be made aware of the high risk for 90-day readmission postoperatively (27.9%) and overall mortality (12.5%). Providers should be aware of the need for multidisciplinary involvement for inpatient care, monitoring postoperative complications, and facilitating discharge planning.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Physical Exercise After Solid Organ Transplantation: A Cautionary Tale

An increasing body of randomized controlled trials suggests the safety of engaging in moderate to vigorous intensity exercise training following solid organ transplantation. Fueled by emerging sport events designed for transplant recipients and the ever-growing body of research highlighting the diverse health benefits of physical activity, transplant recipients are now increasingly participating in strenuous and occasionally competitive physical endeavors that largely surpass those evaluated in controlled research settings. This viewpoint article adopts a cautionary stance to counterbalance the prevalent one-sided optimistic perspective regarding posttransplant physical activity. While discussing methodological limitations, we explore plausible adverse impacts on the cardiovascular, immunological, and musculoskeletal systems. We also examine the physiological consequences of exercising in the heat, at high altitude, and in areas with high air pollution. Risks associated with employing performance-enhancing strategies and the conceivable psychological implications regarding physical activity as a tribute to the 'gift of life' are discussed. With a deliberate focus on the potential adverse outcomes of strenuous posttransplant physical activity, this viewpoint aims to restore a balanced dialogue on our comprehension of both beneficial and potentially detrimental outcomes of physical activity that ultimately underscores the imperative of well-informed decision-making and tailored exercise regimens in the realm of posttransplant care.

Time-Varying Risk Factors for Incident Fractures in Kidney Transplant Recipients: A Nationwide Cohort Study in South Korea

Little is known about the time-varying risk factors for fractures in kidney transplant recipients (KTRs). Using the Korea Organ Transplantation Registry, a nationwide cohort study of KTRs, the incidence, locations, and time-varying predictors of fractures were analyzed, including at baseline and post-transplant 6-month variables in KTRs who underwent KT between January 2014 and June 2019. Among 4134 KTRs, with a median follow-up of 2.94 years (12,441.04 person-years), 63 patients developed fractures. The cumulative 5-year incidence was 2.10%. The most frequent locations were leg (25.40%) and foot/ankle (22.22%). In multivariable analysis, older recipient age at baseline (hazard ratio [HR], 1.035; 95% confidence interval [CI], 1.007–1.064; p = 0.013) and higher tacrolimus trough level (HR, 1.112; 95% CI, 1.029–1.202; p = 0.029) were associated with higher risks for fractures. Pretransplant diabetes mellitus had a time-dependent impact on fractures, with increasing risk as time elapses (HR for diabetes mellitus 1.115; 95% CI, 0.439–2.832; HR for diabetes mellitus × time, 1.049; 95% CI, 1.007–1.094; p = 0.022). In conclusion, KTRs had a high risk of peripheral skeletal fractures in the first 5 years. At baseline recipient age, pretransplant diabetes mellitus and tacrolimus trough level after KT were responsible for the fractures in KTRs.

Intertrochanteric fracture fixation in solid organ transplant patients: outcomes and survivorship

BACKGROUND

Solid organ transplantation (SOT) recipients have complex medical and surgical risk factors; however, the outcomes of these patients undergoing surgical fixation of hip fractures are unknown. This study sought to evaluate SOT patients' outcomes and survivorship after intertrochanteric (IT) fracture fixation.

METHODS

A retrospective review identified 12 SOT patients who underwent cephalomedullary (CMN) nail fixation for IT fractures and were matched (1:2) to a cohort of 24 non-SOT IT fracture patients. Perioperative results and complications, mortality/patient survivorship, and clinical outcomes were compared between the cohorts.

RESULTS

The time from presentation to surgical fixation was within 48 h of presentation for the non-SOT patients, while only 75% of SOT patients underwent surgery within 48 h of presentation (p = 0.034). The 90-day readmission rate for SOT patients was 25% versus 13% in the non-SOT group (p = 0.38). Similarly, the SOT cohort experienced a higher rate of major medical complication (25% vs. 13%, p = 0.38). There were two (16%) reoperations in the SOT group and three (13%) in the non-SOT matched group (p = 0.99). Respectively, the 90-day and 1-year estimated patient survivorship was similar between the two cohorts: SOT patients with 92% (95% CI 54-99%) and 73% (95% CI 24-93%) versus 86% (95% CI 62-95%) and 72% (95% CI 47-86%, HR 0.92, 95% CI 0.18-4.62, p = 0.92) in non-SOT patients.

CONCLUSION

SOT patients who underwent CMN fixation for IT fractures required more time from hospital presentation to surgical management than non-SOT patients. Although not statistically significant, SOT patients demonstrated more acute complications and readmissions, but similar mortality compared to those without transplant.

Characteristics of transplant athletes competing at national and international transplant games

Objective

To describe the characteristics of athletes with solid-organ transplants (TxA) attending the British and World Transplant Games.

Methods

220 TxA completed an online survey to explore transplant history, medications, training advice and support and limitations to training.

Results

TxA were predominantly caucasian, male, kidney recipients in their mid-forties and approximately 11 years post-transplant. The majority of TxA took some form of medication (immunosuppressants 88%, steroids 47%, antihypertensives 47%, statins 28%, antiplatelets 26%, antibiotics/antivirals/antifungals 20%). Stem cell recipients were least likely to require medication. Post-transplant complications were experienced by 40% of TxA, with 53% of these being rejection. Although over half the participants (57%) initially received exercise or training advice post-transplant, only 34% of these received this from their consultants or immediate medical team. Only 1% had been specifically directed towards transplant sport. Half of the TxA (53%) perceived there were limitations preventing them from performing at their potential, 45% considered they did not recover from training as well as non-TxA while 29% felt they trained equally to non-Tx’s. Only 6% considered medication impaired training. TxA competed for a range of reasons from social and health benefits to winning medals.

Conclusions

TxA compete at the British and World Transplant Games for a diverse range of reasons. Athletes manage a range of medications with a range of exercise and health experiences pre-transplant. TxA face a lack of both general and specific exercise training and recovery guidance. The individuality of each TxA‘s background should be considered and is likely reflected in their exercise capacity and goals.

Injury Characteristics and Outcomes of Patients With Inflammatory Bowel Disease After Trauma: A Propensity Score Matched Analysis

BACKGROUND

The clinical course of patients with inflammatory bowel disease (IBD) after trauma is largely unknown. We sought to compare the clinical course of patients with IBD to those without.

METHODS

We conducted a retrospective case-control study of adult patients admitted to a level-1 trauma center from January 1, 2008, through October 1, 2015. Seventy-five patients with IBD were identified. Cases were matched to controls by age, sex, injury severity, and mechanism using 4:1 propensity score-matching analysis. Injury characteristics, clinical course, and infectious and noninfectious complications were compared using bivariate and multivariate analysis.

RESULTS

Participants had a mean age of 56 years and mean injury severity score of 15. Of the 75 cases, 44% had ulcerative colitis, 44% had Crohn's disease, and 12% had undetermined type. More cases were on an immunosuppressant (19% vs 2%, P < 0.01) or steroids (8% vs 2%, P = 0.02) on admission compared with controls. More cases had prior abdominal surgery (P = 0.01). Cases had fewer brain injuries (P = 0.02) and higher admission Glasgow Coma Scale (P < 0.01) but required more neurosurgical intervention (P = 0.03). Cases required more orthopedic surgeries (P < 0.01) and more pain management consultations (P = 0.04). In multivariable analysis, IBD was associated with increased odds of operative intervention, pain management consultation, venous thromboembolism, and longer hospital stay (P < 0.05). Patients on immunosuppressants had increased odds of requiring surgery (P = 0.04), particularly orthopedic surgery (P < 0.01).

CONCLUSIONS

Baseline factors associated with inflammatory bowel disease may place patients at higher risk for surgery and complications after trauma.

Management of Osteoporosis in Survivors of Adult Cancers With Nonmetastatic Disease: ASCO Clinical Practice Guideline

PURPOSE

The aim of this work is to provide evidence-based guidance on the management of osteoporosis in survivors of adult cancer.

METHODS

ASCO convened a multidisciplinary Expert Panel to develop guideline recommendations based on a systematic review of the literature.

RESULTS

The literature search of the 2018 systematic review by the US Preventive Services Task Force in the noncancer population was used as the evidentiary base upon which the Expert Panel based many of its recommendations. A total of 61 additional studies on topics and populations not covered in the US Preventive Services Task Force review were also included. Patients with cancer with metastatic disease and cancer survival outcomes related to bone-modifying agents are not included in this guideline.

RECOMMENDATIONS

Patients with nonmetastatic cancer may be at risk for osteoporotic fractures due to baseline risks or due to the added risks that are associated with their cancer therapy. Clinicians are advised to assess fracture risk using established tools. For those patients with substantial risk of osteoporotic fracture, the clinician should obtain a bone mineral density test. The bone health of all patients may benefit from optimizing nutrition, exercise, and lifestyle. When a pharmacologic agent is indicated, bisphosphonates or denosumab at osteoporosis-indicated dosages are the preferred interventions.

Fractures and Subsequent Graft Loss and Mortality among Older Kidney Transplant Recipients

OBJECTIVES

Older adults who undergo kidney transplantation (KT) are living longer with a functioning graft and are at risk for age-related adverse events including fractures. Understanding recipient, transplant, and donor factors and the outcomes associated with fractures may help identify older KT recipients at increased risk. We determined incidence of hip, vertebral, and extremity fractures; assessed factors associated with incident fractures; and estimated associations between fractures and subsequent death-censored graft loss (DCGL) and mortality.

DESIGN

This was a prospective cohort study of patients who underwent their first KT between January 1, 1999, and December 31, 2014.

SETTING

We linked data from the Scientific Registry of Transplant Recipients to Medicare claims through the US Renal Data System.

PARTICIPANTS

The analytic population included 47 815 KT recipients aged 55 years or older.

MEASUREMENTS

We assessed the cumulative incidence of and factors associated with post-KT fractures (hip, vertebral, or extremity) using competing risks models. We estimated risk of DCGL and mortality after fracture using adjusted Cox proportional hazards models.

RESULTS

The 5-year incidence of post-KT hip, vertebral, and extremity fracture for those aged 65 to 69 years was 2.2%, 1.0%, and 1.7%, respectively. Increasing age was associated with higher hip (adjusted hazard ratio [aHR] = 1.37 per 5-y increase; 95% confidence interval [CI] = 1.30-1.45) and vertebral (aHR = 1.31; 95% CI = 1.20-1.42) but not extremity (aHR = .97; 95% CI = .91-1.04) fracture risk. DCGL risk was higher after hip (aHR = 1.34; 95% CI = 1.12-1.60) and extremity (aHR = 1.30; 95% CI = 1.08-1.57) fracture. Mortality risk was higher after hip (aHR = 2.31; 95% CI = 2.11-2.52), vertebral (aHR = 2.80; 95% CI = 2.44-3.21), and extremity (aHR = 1.85; 95% CI = 1.64-2.10) fracture.

CONCLUSION

Our findings suggest that older KT recipients are at higher risk for hip and vertebral fracture but not extremity fracture; and those with hip, vertebral, or extremity fracture are more likely to experience subsequent graft loss or mortality. These findings underscore that different fracture types may have different underlying etiologies and risks, and they should be approached accordingly. J Am Geriatr Soc 67:1680-1688, 2019.

Mineral and Bone Disease in Kidney Transplant Recipients

PURPOSE OF REVIEW

Despite metabolic improvements following kidney transplantation, transplant recipients still often suffer from complex mineral and bone disease after transplantation.

RECENT FINDINGS

The pathophysiology of post-transplant disease is unique, secondary to underlying pre-transplant mineral and bone disease, immunosuppression, and changing kidney function. Changes in modern immunosuppression regimens continue to alter the clinical picture. Modern management includes reducing cumulative steroid exposure and correcting the biochemical abnormalities in mineral metabolism. While bone mineral density screening appears to help predict fracture risk and anti-osteoporotic therapy appears to have a positive effect on bone mineral density, more data regarding specific treatment is necessary. Patients with mineral and bone disease after kidney transplantation require special care in order to properly manage and mitigate their mineral and bone disease. Recent changes in clinical management of transplant patients may also be changing the implications on patients' mineral and bone disease.

Management of mineral and bone disorders in renal transplant recipients

The management of post-transplantation bone disease is a complex problem that remains under-appreciated in clinical practice. In these patients, pre-existing metabolic bone disorder is further impacted by the use of immunosuppressive medications (glucocorticoids and calcineurin-inhibitors), variable post-transplantation renal allograft function and post-transplantation diabetes mellitus. The treatment of post-transplantation bone loss should begin pre-transplantation. All patients active on transplant waiting lists should be screened for bone disease. Patients should also be encouraged to take preventative measures against osteoporosis such as regular weight-bearing exercise, smoking cessation and reducing alcohol consumption. Biochemical abnormalities of disordered mineral metabolism should be corrected prior to transplantation wherever possible, and because these abnormalities commonly persist, post transplant hypophosphatemia, persistent hyperparathyroidism and low vitamin D levels should be regularly monitored and treated. Bone loss is greatest in the first 6-12 months post-transplantation, during which period any intervention is likely to be of greatest benefit. There is strong evidence that bisphosphonates prevent post-transplantation bone loss; however, data are lacking that this clearly extends to a reduction in fracture incidence. Denosumab is a potential alternative to vitamin D receptor agonists and bisphosphonates in reducing post-transplantation bone loss; however, further studies are needed to demonstrate its safety in patients with a significantly reduced estimated glomerular filtration rate. Clinical judgement remains the cornerstone of this complex clinical problem, providing a strong rationale for the formation of combined endocrinology and nephrology clinics to treat patients with Chronic Kidney Disease-Mineral and Bone Disorder, before and after transplantation.

Osteoporosis in the adult solid organ transplant population: underlying mechanisms and available treatment options

The prevention and treatment of osteoporosis is an increasingly important topic in the solid organ transplant (SOT) population. Compared to the general population, these patients are at an elevated risk of developing osteoporosis due to progressive disease, lifelong immunosuppressant therapy, and malnutrition. As patients live longer after transplant, chronic disease management is increasingly more important. Supplementation with calcium and vitamin D is often necessary in the SOT population due to a high incidence of vitamin D deficiency. Bisphosphonate therapy is most commonly used for prevention and treatment of osteoporosis, but therapy can be limited by renal dysfunction which is common in transplant recipients. Alternative agents such as teriparatide and calcitonin have not been shown to provide a significant impact on the rate of fractures in this population. Additionally, denosumab may be a promising treatment option due to its novel mechanism of action, and is currently being studied in renal transplant patients. Timely initiation of supplementation and treatment, and minimizing glucocorticoid exposure prior to and after transplantation will aid in the prevention and proper management of osteoporosis in these patients.

Bone disease in post-transplant patients

PURPOSE OF REVIEW

Mineral and bone disorders are common problems in organ transplant recipients. Successful transplantation solves many aspects of abnormal mineral and bone metabolism, but the degree of improvement is frequently incomplete. Posttransplant bone disease can affect long-term outcomes as well as increase the likelihood of fracture. In this article, we reviewed the major posttransplant bone diseases and recent advances in treatment strategies.

RECENT FINDINGS

Pretransplant bone disease and immunosuppressants are important risk factors for posttransplant bone disease. Corticosteroid withdrawal may result in minimal or no protection against fractures, with increased risk for acute rejection. Vitamin D analogue and bisphosphonate are frequently used to prevent and treat posttransplant osteoporosis. Posttransplant hyperparathyroidism increases the risk for all-cause mortality and graft loss, but not major cardiovascular events. Cinacalcet was well tolerated and effectively controlled hypercalcemic hyperparathyroidism; however, it did not improve bone mineral density and discontinuation led to parathyroid hormone rebound. Six-month paricalcitol supplementation reduced parathyroid hormone levels and attenuated bone remodeling and mineral loss in case of posttransplant hyperparathyroidism.

SUMMARY

Posttransplant bone diseases present in various forms, including osteoporosis, hyperparathyroidism, adynamic bone disease, and osteonecrosis. Prophylactic and therapeutic approaches to both pretransplant and posttransplant periods should be considered.

Increased incidence of fractures in recipients of hematopoietic stem-cell transplantation

PURPOSE

The number of long-term survivors after hematopoietic stem-cell transplantation (HSCT) for malignant and nonmalignant disorders is increasing, and late effects are gaining importance. Osteoporosis and fractures can worsen the quality of life of HSCT survivors, but the burden of the disease is unknown.

PATIENTS AND METHODS

We conducted a retrospective study of patients older than age 18 years who underwent an HSCT at The University of Texas MD Anderson Cancer Center from January 1, 1997, to December 31, 2011, and were observed until December 31, 2013, to ascertain occurrence of fractures. Cumulative incidence rates of fractures were calculated with death as a competing risk. Age- and sex-specific incidence rates per person-year of fracture were compared with those of the US general population by using estimated rates from the 1994 National Health Interview Survey and the 2004 National Hospital Discharge Survey.

RESULTS

A total of 7,620 patients underwent an HSCT from 1997 to 2011 at the MD Anderson Cancer Center of whom 602 (8%) developed a fracture. Age, underlying disease, and HSCT type were significantly associated with fracture. Age- and sex-specific fracture incidence rates after HSCT were significantly greater than those of the US general population in almost all subgroups. The striking difference was an approximately eight times greater risk in females and approximately seven to nine times greater risk in males age 45 to 64 years old when compared with the National Health Interview Survey and National Hospital Discharge Survey fracture rates.

CONCLUSION

The incidence of fractures is compellingly higher after HSCT.

Hepatic osteodystrophy

Metabolic disturbances of bone are frequent in patients with chronic liver disease. The prevalence of osteoporosis among patients with advanced chronic liver disease is reported between 12% and 55%; it is higher in primary biliary cirrhosis. All patients with advanced liver disease should be screened for osteoporosis with a densitometry, especially if the etiology is cholestatic and in the presence of other risk factors. Clinical relevance of hepatic osteodystrophy increases after liver transplantation. After liver transplant, a rapid loss of bone mineral density can be detected in the first 6 months, followed by stabilization and slight improvement of the values. At the time of transplantation, bone density values are very important prognostic factors. Therapy of hepatic osteodystrophy is based primarily on the control of risk factors: cessation of tobacco and alcohol assumption, reduction of caffeine ingestion, exercise, supplementation of calcium and vitamin D, limitation of drugs such as loop diuretics, corticosteroids, cholestyramine. Bisphosphonates have been proposed for the therapy of osteoporosis in patients with liver disease, particularly after liver transplantation. The possible side effects of oral administration of bisphosphonates, such as the occurrence of esophageal ulcerations, are of particular concern in patients with liver cirrhosis and portal hypertension, due to the risk of gastrointestinal hemorrhage from ruptured esophageal varices, although this risk is probably overestimated.

Kidney transplantation with early corticosteroid withdrawal: paradoxical effects at the central and peripheral skeleton

The use of early corticosteroid withdrawal (ECSW) protocols after kidney transplantation has become common, but the effects on fracture risk and bone quality are unclear. We enrolled 47 first-time adult transplant recipients managed with ECSW into a 1-year study to evaluate changes in bone mass, microarchitecture, biomechanical competence, and remodeling with dual energy x-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HRpQCT), parathyroid hormone (PTH) levels, and bone turnover markers obtained at baseline and 3, 6, and 12 months post-transplantation. Compared with baseline, 12-month areal bone mineral density by DXA did not change significantly at the spine and hip, but it declined significantly at the 1/3 and ultradistal radii (2.2% and 2.9%, respectively; both P<0.001). HRpQCT of the distal radius revealed declines in cortical area, density, and thickness (3.9%, 2.1%, and 3.1%, respectively; all P<0.001), trabecular density (4.4%; P<0.001), and stiffness and failure load (3.1% and 3.5%, respectively; both P<0.05). Findings were similar at the tibia. Increasing severity of hyperparathyroidism was associated with increased cortical losses. However, loss of trabecular bone and bone strength were most severe at the lowest and highest PTH levels. In summary, ECSW was associated with preservation of bone mineral density at the central skeleton; however, it was also associated with progressive declines in cortical and trabecular bone density at the peripheral skeleton. Cortical decreases related directly to PTH levels, whereas the relationship between PTH and trabecular bone decreases was bimodal. Studies are needed to determine whether pharmacologic agents that suppress PTH will prevent cortical and trabecular losses and post-transplant fractures.

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

Osteoporotic fractures are well-known complications of organ transplantation. Fracture rates up to 35% have been previously reported following heart and lung transplantations. Our institutional pretransplant protocols include DXA scans, vitamin D screening, and appropriate antiresorptive therapy. We aimed to assess the incidence of fragility fractures following cardiac or lung transplantation. In a retrospective study 210 electronic medical records of patients who underwent LT (110 men, 100 women) and 105 HT (88 men, 17 women) between 2005 and 2010 were analyzed. Both clinical and radiographic fractures were recorded. DXA scans were obtained immediately after transplant. 17 out of 210 LT patients (8.0%) had fractures after transplantation and 9 out of 105 HT patients (8.6%) had fractures. The median time to the first fracture was 12 months and the mean time was 18 months for both LT and HT. In the HT recipients, the median femoral neck T score was statistically lower in the fracture group versus the nonfracture group. Similar results were seen in the LT patients. Conclusion. Our findings demonstrate a much lower incidence of fractures in heart and lung transplant recipients in comparison with earlier reports. Comprehensive bone care and early initiation of antiresorptive therapy are possible contributors to these improved outcomes.

Fracture risk in kidney transplant recipients: a systematic review

BACKGROUND

Fractures in men and women after kidney transplantation are associated with morbidity (including acute and chronic pain), mortality, and high economic costs.

METHODS

We systematically reviewed cohort studies that provided estimates on incidence and risk factors for fracture in kidney transplant recipients. We abstracted data in duplicate and assessed the methodological quality of each study on a 17-point scale (17 representing the highest quality).

RESULTS

We screened 2715 articles, reviewed 81, and included 10 studies totaling 262,678 recipients (study mean, 26,268 recipients; range, 61-77,430). The average follow-up ranged from 1.7 to 5.3 years. The study quality scores ranged from 8 to 13. Fracture sites varied by study resulting in a highly variable incidence rate ranging from 3.3 to 99.6 fractures per 1000 person-years. Similarly, the 5-year cumulative incidence for fracture varied ranging from 0.85% to 27%. Common factors associated with an increased fracture risk were older age, female sex, the presence of diabetes, and receipt of dialysis before transplantation. Other less common but statistically significant risk factors were a previous history of fracture and receipt of a kidney from a deceased (vs. living) donor.

CONCLUSIONS

There is poor consensus on the incidence and risk factors for fractures in kidney transplant recipients. Previous studies vary substantially in quality, fracture definitions, and the characteristics of recipients studied. Future research should clarify fracture incidence and risk, which will inform the design of future prevention trials and guide prognostication.

CKD-mineral and bone disorder management in kidney transplant recipients

Kidney transplantation, the most effective treatment for the metabolic abnormalities of chronic kidney disease (CKD), only partially corrects CKD-mineral and bone disorders. Posttransplantation bone disease, one of the major complications of kidney transplantation, is characterized by accelerated loss of bone mineral density and increased risk of fractures and osteonecrosis. The pathogenesis of posttransplantation bone disease is multifactorial and includes the persistent manifestations of pretransplantation CKD-mineral and bone disorder, peritransplantation changes in the fibroblast growth factor 23-parathyroid hormone-vitamin D axis, metabolic perturbations such as persistent hypophosphatemia and hypercalcemia, and the effects of immunosuppressive therapies. Posttransplantation fractures occur more commonly at peripheral than central sites. Although there is significant loss of bone density after transplantation, the evidence linking posttransplantation bone loss and subsequent fracture risk is circumstantial. Presently, there are no prospective clinical trials that define the optimal therapy for posttransplantation bone disease. Combined pharmacologic therapy that targets multiple components of the disordered pathways has been used. Although bisphosphonate or calcitriol therapy can preserve bone mineral density after transplantation, there is no evidence that these agents decrease fracture risk. Moreover, bisphosphonates pose potential risks for adynamic bone disease.