Interventions for preventing bone disease in kidney transplant recipients

Impact of bisphosphonate treatment on bone mineral density after kidney transplant

BACKGROUND

Mineral bone disease is associated with chronic kidney disease and persists after kidney transplantation. Immunosuppressive treatment contributes to the pathogenesis of this disease. Bisphosphonate treatments have shown positive but indefinite results.

AIM

To evaluate the effectiveness and safety of bisphosphonate treatment on post kidney transplantation bone mineral density (BMD).

METHODS

We included kidney transplant recipients (KTRs) whose BMD was measured after the operation but before the initiation of treatment and their BMD was measured at least one year later. We also evaluated the BMD of KTRs using two valid measurements after transplantation who received no treatment (control group).

RESULTS

Out of 254 KTRs, 62 (39 men) were included in the study. Bisphosphonates were initiated in 35 KTRs in total (20 men), 1.1 ± 2.4 years after operation and for a period of 3.9 ± 2.3 years while 27 (19 men) received no treatment. BMD improved significantly in KTRs who received bisphosphonate treatments (from -2.29 ± 1.07 to -1.66 ± 1.09, P < 0.0001). The control group showed a non-significant decrease in BMD after 4.2 ± 1.4 years of follow-up after surgery. Kidney function was not affected by bisphosphonate treatment. In KTRs with established osteoporosis, active treatment had a similar and significant effect on those with osteopenia or normal bone mass.

CONCLUSION

In this retrospective study of KTRs receiving bisphosphonate treatment, we showed that active treatment is effective in preventing bone loss irrespective of baseline BMD.

Bone health and fracture prevention after kidney transplantation

Changes in bone health and strength are common after kidney transplantation and can lead to an increased risk of fracture. This has implications for morbidity, mortality and renal allograft survival. This review will focus on the changes that occur in bone health and fracture risk after kidney transplantation and examine the evidence available to guide diagnostic and therapeutic decisions with the aim of fracture prevention.

Urinary collagen peptides: Source of markers for bone metabolic processes in kidney transplant recipients

INTRODUCTION

Kidney transplant recipients (KTRs) are at an increased risk of fractures. Total urinary hydroxyproline excretion served as marker for bone resorption (BR) but was replaced by β-CrossLaps (CTX), a C-terminal collagen α-1(I) chain (COL1A1) telopeptide. We investigated the low-molecular-weight urinary proteome for peptides associated with changes in bone metabolism after kidney transplantation.

METHODS

Clinical and laboratory data including serum levels of CTX in 96 KTR from two nephrology centers were correlated with signal intensities of urinary peptides identified by capillary electrophoresis mass spectrometry.

RESULTS

Eighty-two urinary peptides were significantly correlated with serum CTX levels. COL1A1 was the predominant peptide source. Oral bisphosphonates were administered for decreased bone density in an independent group of 11 KTR and their effect was evaluated on the aforementioned peptides. Study of the peptides cleavage sites revealed a signature of Cathepsin K and MMP9. Seventeen of these peptides were significantly associated with bisphosphonate treatment, all showing a marked reduction in their excretion levels compared to baseline.

DISCUSSION

This study provides strong evidence for the presence of collagen peptides in the urine of KTR that are associated with BR and that are sensitive to bisphosphonate treatment. Their assessment might become a valuable tool to monitor bone status in KTR.

Prevention and Treatment of Glucocorticoid-Induced Osteoporosis in Adults: Consensus Recommendations From the Belgian Bone Club

Glucocorticoids are effective immunomodulatory drugs used for many inflammatory disorders as well as in transplant recipients. However, both iatrogenic and endogenous glucocorticoid excess are also associated with several side effects including an increased risk of osteoporosis and fractures. Glucocorticoid-induced osteoporosis (GIOP) is a common secondary cause of osteoporosis in adults. Despite availability of clear evidence and international guidelines for the prevention of GIOP, a large treatment gap remains. In this narrative review, the Belgian Bone Club (BBC) updates its 2006 consensus recommendations for the prevention and treatment of GIOP in adults. The pathophysiology of GIOP is multifactorial. The BBC strongly advises non-pharmacological measures including physical exercise, smoking cessation and avoidance of alcohol abuse in all adults at risk for osteoporosis. Glucocorticoids are associated with impaired intestinal calcium absorption; the BBC therefore strongly recommend sufficient calcium intake and avoidance of vitamin D deficiency. We recommend assessment of fracture risk, taking age, sex, menopausal status, prior fractures, glucocorticoid dose, other clinical risk factors and bone mineral density into account. Placebo-controlled randomized controlled trials have demonstrated the efficacy of alendronate, risedronate, zoledronate, denosumab and teriparatide in GIOP. We suggest monitoring by dual-energy X-ray absorptiometry (DXA) and vertebral fracture identification one year after glucocorticoid initiation. The trabecular bone score might be considered during DXA monitoring. Extended femur scans might be considered at the time of DXA imaging in glucocorticoid users on long-term (≥ 3 years) antiresorptive therapy. Bone turnover markers may be considered for monitoring treatment with anti-resorptive or osteoanabolic drugs in GIOP. Although the pathophysiology of solid organ and hematopoietic stem cell transplantation-induced osteoporosis extends beyond GIOP alone, the BBC recommends similar evaluation, prevention, treatment and follow-up principles in these patients. Efforts to close the treatment gap in GIOP and implement available effective fracture prevention strategies into clinical practice in primary, secondary and tertiary care are urgently needed.

The Influence of Parathyroidectomy on Osteoporotic Fractures in Kidney Transplant Recipients: Results from a Retrospective Single-Center Trial

Kidney transplant (KTx) recipients are a high-risk population for osteoporotic fractures. We herein aim to identify the role of pre-transplant parathyroidectomy (PTX) and other modifiable factors associated with osteoporotic fractures in KTx recipients. We conducted a retrospective study involving 711 adult patients (4608 patient-years) who were transplanted at our center between January 2007 and June 2015. Clinical data were extracted from patients' electronic medical records. Different laboratory and clinical parameters for mineral bone disease (MBD) and osteoporosis, including medication, were evaluated. We chose fracture events unrelated to malignancies or adequate trauma as the primary endpoint. Osteoporotic fractures occurred in 47 (6.6%) patients (median 36.7 months, IQR 45.9) after KTx (fracture incidence of 10 per 1000 person-years). Prior to KTx, subtotal PTX was performed in 116 patients (16.3%, median time 4.2 years before KTx, IQR 5.0). Of the patients with fracture (n = 47), only one (2.2%) patient had previously undergone PTX. After adjusting for the known fracture risk factors MBD and osteoporosis, PTX remained a protective factor against fractures (HR 0.134, CI 0.018-0.991, p = 0.049). We observed a reduced risk for pathological fractures in KTx patients who underwent PTX, independent from elevated parathyroid hormone at the time of KTx or afterwards.

Optimization of osteoporosis and osteopenia management among renal transplant recipients

Background

Osteoporosis and osteopenia occur frequently in renal transplant recipients due to long-term use of immune-suppressants including corticosteroids. Previous treatment options like bisphosphonates had acceptable but rather unsatisfactory results after transplant. The aim of the current study is to directly compare the efficacy of denosumab and oral ibandronate in late RTR with low bone mineral density.

Results

The study was conducted Iin Hamed Al-Essa Kidney transplant center, Kuwait, in 2020. The data of 52 denosumab and 48 ibandronate patients were collected at the baseline and after one year of treatment. Spine and hip T-score readings, side effects, and other laboratory results were analyzed to evaluate the use of both medications. The mean number of months after transplant was 25 (± 13.9) months. After one year of treatment, denosumab alleviated both spinal osteoporosis and osteopenia T-score values from −3.13 to −2.4 (p = 0.008) and from −1.9 to −1.5 (p = 0.015), respectively. Besides, it reduced hip osteoporosis and osteopenia insignificantly from −3.45 to −3.1 and from −1.5 to −1.3, respectively (p > 0.05). Ibandronate improved spinal osteopenia from −1.6 to −1.55 (p = 0.97) and failed to show any positive impact on other sites; the spinal osteoporosis changed from −2.8 to −3 and hip osteoporosis and osteopenia changed from −3.1 to −3.12 and from −1.4 to −1.45, respectively (p > 0.05). The use of ibandronate was more associated with gastrointestinal tract (GIT) side effects, while hypocalcemia episodes were significantly higher in the denosumab group.

Conclusion

Denosumab improved both spinal and hip T-score values in comparison with ibandronate in RTR. Close monitoring is required for denosumab patients to prevent the associated hypocalcemia.

Graphical Abstract

Osteoporosis, an Inevitable Circumstance of Chronic Kidney Disease: A Systematic Review

Nowadays, chronic kidney disease (CKD) and osteoporosis have become crucial health-related issues globally. CKD-induced osteoporosis is a systemic disease characterized by the disruption of mineral, hormone, and vitamin homeostasis that elevates the likelihood of fracture. Here, we review recent studies on the association of CKD and osteoporosis. In particular, we focus on the pathogenesis of CKD-associated osteoporosis, including the homeostasis and pathways of several components such as parathyroid hormone, calcium, phosphate, vitamin D, fibroblast growth factor, and klotho, as well as abnormal bone mineralization, remodeling, and turnover. In addition, we explore the diagnostic tools and possible therapeutic approaches for the management and prevention of CKD-associated osteoporosis. Patients with CKD show higher osteoporosis prevalence, greater fracture rate, increased morbidity and mortality, and an elevated occurrence of hip fracture. We also rule out that increased severity of CKD is related to a more severe condition of osteoporosis. Furthermore, supplements such as calcium and vitamin D as well as lifestyle modifications such as exercise and cessation of smoking and alcohol help in fracture prevention. However, new approaches and advancements in treatment are needed to reduce the fracture risk in patients with CKD. Therefore, further collaborative multidisciplinary research is needed in this regard.

Denosumab-Induced Hypocalcemia and Hyperparathyroidism in de novo Kidney Transplant Recipients

INTRODUCTION

Denosumab represents a realistic treatment option to increase bone mineral density in kidney transplant recipients (KTRs). It is still unknown how and at what extent posttransplantation bone disease and graft function influence the effects of denosumab on mineral metabolism indexes. In this study, we analyze risk factors of hypocalcemia and parathyroid hormone (PTH) increase after denosumab administration in eighteen de novo KTRs and its management before and after this treatment.

METHODS

We conducted a monocentric, observational, prospective study on de novo KTRs. All KTRs enrolled received a single 60 mg subcutaneous dose of denosumab every 6 months. Before kidney transplantation, no patients were treated with calcio-mimetic. After kidney transplantation and before antiresorptive therapy, no patients were treated with calcio-mimetic drugs and/or vitamin D receptor agonists, while all patients received nutritional vitamin D supplementation (from 1,000 IU to 1,500 IU daily).

RESULTS

Hypocalcemia was related to the degree of lumbar osteoporosis (p = 0.047); the increase in the PTH level was correlated to baseline bone turnover markers (bone alkaline phosphatase, serum osteocalcin, and β-C-terminal telopeptide), the 25 OH status, and eGFR. The introduction of calcitriol, after the PTH increase, in addition to cholecalciferol was necessary to ensure an adequate control of serum calcium and PTH during a follow-up of 15 months. Following the treatment with denosumab, it was observed an improvement of areal bone mineral density both at lumbar and femoral sites with a mean percentual increase of 1.74% and 0.25%, respectively.

CONCLUSIONS

Denosumab is an effective treatment for bone disease in KTRs. In our study, the increase in PTH is not a transient event but prolonged throughout the follow-up period and requires continuous supplementation therapy with calcitriol.

Pharmacological interventions versus placebo, no treatment or usual care for osteoporosis in people with chronic kidney disease stages 3-5D

BACKGROUND

Chronic kidney disease (CKD) is an independent risk factor for osteoporosis and is more prevalent among people with CKD than among people who do not have CKD. Although several drugs have been used to effectively treat osteoporosis in the general population, it is unclear whether they are also effective and safe for people with CKD, who have altered systemic mineral and bone metabolism.

OBJECTIVES

To assess the efficacy and safety of pharmacological interventions for osteoporosis in patients with CKD stages 3-5, and those undergoing dialysis (5D).

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 25 January 2021 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials comparing any anti-osteoporotic drugs with a placebo, no treatment or usual care in patients with osteoporosis and CKD stages 3 to 5D were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed their quality using the risk of bias tool, and extracted data. The main outcomes were the incidence of fracture at any sites; mean change in the bone mineral density (BMD; measured using dual-energy radiographic absorptiometry (DXA)) of the femoral neck, total hip, lumbar spine, and distal radius; death from all causes; incidence of adverse events; and quality of life (QoL). Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Seven studies involving 9164 randomised participants with osteoporosis and CKD stages 3 to 5D met the inclusion criteria; all participants were postmenopausal women. Five studies included patients with CKD stages 3-4, and two studies included patients with CKD stages 5 or 5D. Five pharmacological interventions were identified (abaloparatide, alendronate, denosumab, raloxifene, and teriparatide). All studies were judged to be at an overall high risk of bias. Among patients with CKD stages 3-4, anti-osteoporotic drugs may reduce the risk of vertebral fracture (RR 0.52, 95% CI 0.39 to 0.69; low certainty evidence). Anti-osteoporotic drugs probably makes little or no difference to the risk of clinical fracture (RR 0.91, 95% CI 0.79 to 1.05; moderate certainty evidence) and adverse events (RR 0.99, 95% CI 0.98 to 1.00; moderate certainty evidence). We were unable to incorporate studies into the meta-analyses for BMD at the femoral neck, lumbar spine and total hip as they only reported the percentage change in the BMD in the intervention group. Among patients with severe CKD stages 5 or 5D, it is uncertain whether anti-osteoporotic drug reduces the risk of clinical fracture (RR 0.33, 95% CI 0.01 to 7.87; very low certainty evidence). It is uncertain whether anti-osteoporotic drug improves the BMD at the femoral neck because the certainty of this evidence is very low (MD 0.01, 95% CI 0.00 to 0.02). Anti-osteoporotic drug may slightly improve the BMD at the lumbar spine (MD 0.03, 95% CI 0.03 to 0.04, low certainty evidence). No adverse events were reported in the included studies. It is uncertain whether anti-osteoporotic drug reduces the risk of death (RR 1.00, 95% CI 0.22 to 4.56; very low certainty evidence).

AUTHORS' CONCLUSIONS

Among patients with CKD stages 3-4, anti-osteoporotic drugs may reduce the risk of vertebral fracture in low certainty evidence. Anti-osteoporotic drugs make little or no difference to the risk of clinical fracture and adverse events in moderate certainty evidence. Among patients with CKD stages 5 and 5D, it is uncertain whether anti-osteoporotic drug reduces the risk of clinical fracture and death because the certainty of this evidence is very low. Anti-osteoporotic drug may slightly improve the BMD at the lumbar spine in low certainty evidence. It is uncertain whether anti-osteoporotic drug improves the BMD at the femoral neck because the certainty of this evidence is very low. Larger studies including men, paediatric patients or individuals with unstable CKD-mineral and bone disorder are required to assess the effect of each anti-osteoporotic drug at each stage of CKD.

Bone Mineral Disease After Kidney Transplantation

Chronic kidney disease-mineral bone disorder (CKD-MBD) after kidney transplantation is a mix of pre-existing disorders and new alterations. The final consequences are reflected fundamentally as abnormal mineral metabolism (hypercalcemia, hypophosphatemia) and bone alterations [high or low bone turnover disease (as fibrous osteitis or adynamic bone disease), an eventual compromise of bone mineralization, decrease bone mineral density and bone fractures]. The major cause of post-transplantation hypercalcemia is the persistence of severe secondary hyperparathyroidism, and treatment options include calcimimetics or parathyroidectomy. On turn, hypophosphatemia is caused by both the persistence of high blood levels of PTH and/or high blood levels of FGF23, with its correction being very difficult to achieve. The most frequent bone morphology alteration is low bone turnover disease, while high-turnover osteopathy decreases in frequency after transplantation. Although the pathogenic mechanisms of these abnormalities have not been fully clarified, the available evidence suggests that there are a number of factors that play a very important role, such as immunosuppressive treatment, persistently high levels of PTH, vitamin D deficiency and hypophosphatemia. Fracture risk is four-fold higher in transplanted patients compared to general population. The most relevant risk factors for fracture in the kidney transplant population are diabetes mellitus, female sex, advanced age (especially > 65 years), dialysis vintage, high PTH levels and low phosphate levels, osteoporosis, pre-transplant stress fracture and high doses or prolonged steroids therapy. Treatment alternatives for CKD-MBD after transplantation include minimization of corticosteroids, use of calcium and vitamin D supplements, antiresorptives (bisphosphonates or Denosumab) and osteoformers (synthetic parathyroid hormone). As both mineral metabolism and bone disorders lead to increased morbidity and mortality, the presence of these changes after transplantation has to be prevented (if possible), minimized, diagnosed, and treated as soon as possible.

Interventions for preventing bone disease in kidney transplant recipients

BACKGROUND

People who have chronic kidney disease (CKD) have important changes to bone structure, strength, and metabolism. Children experience bone deformity, pain, and delayed or impaired growth. Adults experience limb and vertebral fractures, avascular necrosis, and pain. The fracture risk after kidney transplantation is four times that of the general population and is related to Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD) occurring with end-stage kidney failure, steroid-induced bone loss, and persistent hyperparathyroidism after transplantation. Fractures may reduce quality of life and lead to being unable to work or contribute to community roles and responsibilities. Earlier versions of this review have found low certainty evidence for effects of treatment. This is an update of a review first published in 2005 and updated in 2007.

OBJECTIVES

This review update evaluates the benefits and harms of interventions for preventing bone disease following kidney transplantation.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 16 May 2019 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

RCTs and quasi-RCTs evaluating treatments for bone disease among kidney transplant recipients of any age were eligible.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial risks of bias and extracted data. Statistical analyses were performed using random effects meta-analysis. The risk estimates were expressed as a risk ratio (RR) for dichotomous variables and mean difference (MD) for continuous outcomes together with the corresponding 95% confidence interval (CI). The primary efficacy outcome was bone fracture. The primary safety outcome was acute graft rejection. Secondary outcomes included death (all cause and cardiovascular), myocardial infarction, stroke, musculoskeletal disorders (e.g. skeletal deformity, bone pain), graft loss, nausea, hyper- or hypocalcaemia, kidney function, serum parathyroid hormone (PTH), and bone mineral density (BMD).

MAIN RESULTS

In this 2019 update, 65 studies (involving 3598 participants) were eligible; 45 studies contributed data to our meta-analyses (2698 participants). Treatments included bisphosphonates, vitamin D compounds, teriparatide, denosumab, cinacalcet, parathyroidectomy, and calcitonin. Median duration of follow-up was 12 months. Forty-three studies evaluated bone density or bone-related biomarkers, with more recent studies evaluating proteinuria and hyperparathyroidism. Bisphosphonate therapy was usually commenced in the perioperative transplantation period (within 3 weeks) and regardless of BMD. Risks of bias were generally high or unclear leading to lower certainty in the results. A single study reported outcomes among 60 children and adolescents. Studies were not designed to measure treatment effects on fracture, death or cardiovascular outcomes, or graft loss.Compared to placebo, bisphosphonate therapy administered over 12 months in transplant recipients may prevent fracture (RR 0.62, 95% CI 0.38 to 1.01; low certainty evidence) although the 95% CI included the possibility that bisphosphonate therapy might make little or no difference. Fracture events were principally vertebral fractures identified during routine radiographic surveillance. It was uncertain whether any other drug class decreased fracture (low or very low certainty evidence). It was uncertain whether interventions for bone disease in kidney transplantation reduce all-cause or cardiovascular death, myocardial infarction or stroke, or graft loss in very low certainty evidence. Bisphosphonate therapy may decrease acute graft rejection (RR 0.70, 95% CI 0.55 to 0.89; low certainty evidence), while it is uncertain whether any other treatment impacts graft rejection (very low certainty evidence). Bisphosphonate therapy may reduce bone pain (RR 0.20, 95% CI 0.04 to 0.93; very low certainty evidence), while it was very uncertain whether bisphosphonates prevent spinal deformity or avascular bone necrosis (very low certainty evidence). Bisphosphonates may increase to risk of hypocalcaemia (RR 5.59, 95% CI 1.00 to 31.06; low certainty evidence). It was uncertain whether vitamin D compounds had any effect on skeletal, cardiovascular, death, or transplant function outcomes (very low certainty or absence of evidence). Evidence for the benefits and harms of all other treatments was of very low certainty. Evidence for children and young adolescents was sparse.

AUTHORS' CONCLUSIONS

Bisphosphonate therapy may reduce fracture and bone pain after kidney transplantation, however low certainty in the evidence indicates it is possible that treatment may make little or no difference. It is uncertain whether bisphosphonate therapy or other bone treatments prevent other skeletal complications after kidney transplantation, including spinal deformity or avascular bone necrosis. The effects of bone treatment for children and adolescents after kidney transplantation are very uncertain.