Avascular osteonecrosis in kidney transplant recipients: Risk factors in a recent cohort study and evaluation of the role of secondary hyperparathyroidism

Advances in mechanism and management of bone homeostasis in osteonecrosis: a review article from basic to clinical applications

Osteonecrosis, characterized by bone cell death leading to impaired bone recovery, causes challenges in bone homeostasis maintenance. Bone homeostasis relies on the delicate balance between osteoclasts and osteoblasts, encompassing a series of complex and strictly regulated biological functions. Current treatments, including conservative therapies and surgeries, often fall short of expected outcomes, necessitating a reorientation towards more effective therapeutic strategies according to the pathogenesis. In this review, the authors hierarchically outlined risk factors, emerging mechanisms, and last-decade treatment approaches in osteonecrosis. By connecting mechanisms of bone homeostasis, the authors proposed future research directions should be focused on elucidating risk factors and key molecules, performing high-quality clinical trial, updating practice, and accelerating translational potential.

Avascular Necrosis in Kidney Transplant Recipients is Associated With an Increased Risk of Patient Death

Introduction: Avascular necrosis is a debilitating osseous complication in transplant recipients. Project Aim: This program evaluation sought to describe risk factors and adverse outcomes of avascular necrosis in kidney transplant recipients. Design: This was a retrospective evaluation of all recipients of kidneys and simultaneous pancreas and kidneys between 2001 and 2018 from a single center. Controls were selected based on the incidence density, sampling at a 1:3 ratio based on the post-transplant interval. Outcomes of interest were acute rejection, death-censored graft failure, and patient mortality. Results: A total of 88 kidney recipients had avascular necrosis and were compared with 257 controls. Most of the recipient's and donors' baseline characteristics were similar between the groups, except calcineurin inhibitor-based immunosuppression was more prevalent, and non-white donors were less prevalent in the control group. Looking for risk factors for avascular necrosis, calcineurin inhibitor-based immunosuppression was associated with a lower risk for avascular necrosis in the univariate analysis, but this was not found after adjustment of multiple variables. In multivariate analysis, avascular necrosis was associated with an increased risk for patient death (hazard ratio: 1.68; 95% confidence interval: 1.16-2.44; P = .008) but not for acute rejection or death censored graft failure. Conclusion: Although limited by small sample size, this evaluation found avascular necrosis to be associated with an increased risk of patient death. This finding may be useful for the provider taking care of the patients and discussing the various outcomes after the transplant.

No evidence of genetic causality between diabetes and osteonecrosis: a bidirectional two-sample Mendelian randomization analysis

OBJECTIVE

This study aimed to examine whether diabetes mellitus is causally associated with osteonecrosis.

METHOD

Using publicly accessible genome-wide association study statistics, a bidirectional two-sample Mendelian randomization analysis was carried out. In order to determine whether diabetes has a causal effect on osteonecrosis and whether osteonecrosis has a causal effect on diabetes, we extracted six date on diabetes in Europeans from IEU OpenGWAS and GWAS Catalogue and osteonecrosis in Europeans from FinnGen. We then evaluated the data using inverse variance weighting, MR-Egger regression, weighted median, weighted mode, and simple mode. The results' stability and dependability were then evaluated using sensitivity analysis and heterogeneity analysis. Finally, meta-analysis is used to further confirm if there is a relationship between diabetes and osteonecrosis.

RESULTS

When diabetes was used as an exposure factor, MR-Egger regression showed that directional fold product was unlikely to bias the results. Cochran's Q test showed only minor heterogeneity in a few data sets. Multidirectional tests Egger-intercept, MR-PRESSO and funnel plots for most data did not show multidirectional and asymmetry at the gene level. Most of the IVW results showed no causal relationship between diabetes mellitus and osteonecrosis. The results of meta-analysis of IVW methods further confirmed the absence of a causal relationship. Inverse MR analysis also showed no causal relationship between osteonecrosis and diabetes.

CONCLUSION

Results of bidirectional MR analysis show no evidence of causal relationship between diabetes and osteonecrosis.

Does Diabetes Mellitus Increase the Risk of Avascular Osteonecrosis? A Systematic Review and Meta-Analysis

Avascular osteonecrosis (AVN) is caused by the disrupted blood supply to the bone. Most AVN cases occur in the femoral head, but other sites might be affected as well, including the jaw or distal bones of the extremities. Previous studies suggested that diabetes could increase the risk of AVN of the jaw, but the relationship between diabetes and AVN in other bone sites is unclear. This systematic review and meta-analysis aimed to summarize the evidence from studies that had reported on the occurrence of AVN in sites other than the jaw, depending on the diagnosis of diabetes. Overall, we included 6 observational studies carried out in different populations: primary or secondary AVN of the femoral head, Takayasu arteritis, general population, kidney transplant recipients, systemic lupus erythematosus, and primary brain tumors. A random-effects meta-analysis showed that the risk of AVN in sites other than the jaw was non-significantly increased in patients with diabetes (odds ratio: 1.90, 95% confidence interval: 0.93-3.91). The pooled estimate increased and was significant after the exclusion of one study (2.46, 1.14-5.32). There was a significant heterogeneity (I² = 65%, tau² = 0.48, p = 0.01; prediction interval, 0.21-16.84). There was no significant publication bias (p = 0.432). In conclusion, diabetes could increase the risk of AVN in sites other than the jaw, but the available evidence is limited. There is a need for large, well-designed, population-based studies.

Outcomes following Total Hip Arthroplasty for Femoral Head Osteonecrosis in Patients with History of Solid Organ Transplant

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is a potentially debilitating condition, often requiring total hip arthroplasty (THA). Patients with solid organ transplant (SOT) are at increased risk of postoperative complications after THA for osteoarthritis. The objective of the present study is to evaluate SOT as a potential risk factor for complication after THA for ONFH.

METHODS

This is a retrospective study that identified patients with SOT who underwent THA for ONFH from 2005 to 2014 in a national insurance database and compared them to 5:1 matched controls without transplant. Subgroup analyses of patients with renal transplant (RT) and those with non-RT were also analyzed. A logistic regression analysis was used to compare rates of mortality, hospital readmission, emergency room (ER) visits, infection, revision, and dislocation while controlling for confounders. Differences in hospital charges, reimbursement, and length of stay (LOS) were also compared.

RESULTS

996 patients with SOT who underwent THA were identified and compared to 4,980 controls. SOT patients experienced no increased risk of early postoperative complications compared to controls. Solid organ transplant was associated with higher resource utilization and LOS. Renal transplant patients were found to have significantly higher risk of hospital readmission at 30 days (odds ratio [OR] 1.77; p = 0.001) and 90 days (OR 1.62; p < 0.001) and hospital LOS (p < 0.001), but had lower risk of infection (OR 0.65; p = 0.030). Non-RT patients had higher rate of ER visits at 30 days (OR 2.26; p = 0.004) but lower rates of all-cause revision (OR 0.22; p = 0.043).

CONCLUSIONS

Patients with history of SOT undergoing THA for ONFH utilize more hospital resources with longer LOS and greater risk of readmission but are not necessarily at an increased risk of early postoperative complications.

Long-lasting severe knee pain in a SLE patient after renal transplantation: what is the reason? A case report and literature review

Musculo-skeletal complaints in a patient suffering from systemic lupus, with co-existing chronic renal failure, undergoing immunosuppressive treatment after kidney transplantation, can have a varied etiology. The aim of this work was to present a case based review of differential diagnosis of knee pain in such a patient. A literature search was carried out using MEDLINE/PubMed, Google Scholar and EBSCO, with no time limit. We undertook a systematic review of the literature published in English, limited to full-text publications of original articles, letters to the editor, and case reports in peer-reviewed journals, for a discussion and analysis of studies reporting arthralgia in patients with lupus after kidney transplantation. We present a case report of a 45-year-old woman with lupus nephritis, after kidney transplantation, who started to complain of increasing pain in the knees, most pronounced at night and after physical activity approximately 2 years after transplantation. Extensive causal diagnostics were carried out, which revealed bilateral extensive regions of bone infarction in the femur and tibia, chondropathy, degenerative changes of medial meniscuses in the body and posterior horn as well as chondromalacia of the patella. Establishing the right diagnosis is crucial for implementing appropriate treatment.

Current status of glucocorticoid usage in solid organ transplantation

Glucocorticoids (GCs) have been the mainstay of immunosuppressive therapy in solid organ transplantation (SOT) for decades, due to their potent effects on innate immunity and tissue protective effects. However, some SOT centers are reluctant to administer GCs long-term because of the various related side effects. This review summarizes the advantages and disadvantages of GCs in SOT. PubMed and Scopus databases were searched from 2011 to April 2021 using search syntaxes covering “transplantation” and “glucocorticoids”. GCs are used in transplant recipients, transplant donors, and organ perfusate solution to improve transplant outcomes. In SOT recipients, GCs are administered as induction and maintenance immunosuppressive therapy. GCs are also the cornerstone to treat acute antibody- and T-cell-mediated rejections. Addition of GCs to organ perfusate solution and pretreatment of transplant donors with GCs are recommended by some guidelines and protocols, to reduce ischemia-reperfusion injury peri-transplant. GCs with low bioavailability and high potency for GC receptors, such as budesonide, nanoparticle-mediated targeted delivery of GCs to specific organs, and combination use of dexamethasone with inducers of immune-regulatory cells, are new methods of GC application in SOT patients to reduce side effects or induce immune-tolerance instead of immunosuppression. Various side effects involving different non-targeted organs/tissues, such as bone, cardiovascular, neuromuscular, skin and gastrointestinal tract, have been noted for GCs. There are also potential drug-drug interactions for GCs in SOT patients.

A Case of Multi-focal Osteonecrosis in the Context of Liver Transplant Following Ingestion of Amanita phalloides Mushroom Toxin

We present the case of a 44-year-old female who presented with atraumatic avascular necrosis (AVN) of the patella and hips bilaterally, following ingestion of the deadly fungus Amanita phalloides or ‘death cap’ and subsequent liver transplant. Upon presentation, in the hours following ingestion, our patient required a liver transplant and ICU admission. She was treated by a multidisciplinary team, with input from various specialities. Our patient required steroids in the months following this event. Six months after the liver transplant and subsequent ICU admission, our patient developed hip pain, thus limiting her mobility, ability to engage in physiotherapy and rehabilitation. X-rays were performed that excluded any acute pathology. She was still receiving high-dose steroids at this time. When the pain did not resolve with analgesia, MRI of pelvis and knee was performed and the patient was found to have polyarticular AVN. Acute bilateral total hip replacement was performed and within weeks, the patient returned to physiotherapy and to full rehabilitation. Conservative management of the patella was favoured. Over two years later, the patient can now mobilise independently.

The role of acute total hip replacement is evident in this case, and how in performing this surgery, the overall conditioning and health of our patient improved drastically. Currently, cases reporting A. phalloides ingestion are few and we wish to use this case to highlight the differential diagnosis in a patient presenting with joint pain in this context of fungus ingestion, organ transplant or prolonged steroid use.

Risk factors for symptomatic Avascular Necrosis (AVN) in a multi-ethnic Systemic Lupus Erythematosus (SLE) cohort

Avascular necrosis of bone (AVN) is increasingly being recognized as a complication of SLE and causes significant disability due to pain and mobility limitations. We studied the prevalence and factors associated with avascular necrosis (AVN) in a multiethnic SLE cohort. SLE patients who visited the outpatient clinic from October 2017 to April 2019 were considered eligible. Their medical records were reviewed to identify patients who developed symptomatic AVN, as confirmed by either magnetic resonance imaging or plain radiography. Subsequently, their SLE disease characteristics and treatment were compared with the characteristics of patients who did not have AVN. Multivariable logistic regression analyses were performed to determine the independent factors associated with AVN among the multiethnic SLE cohort. A total of 390 patients were recruited, and the majority of them were females (92.6%); the patients were predominantly of Malay ethnicity (59.5%), followed by Chinese (35.9%) and Indian (4.6%). The prevalence of symptomatic AVN was 14.1%, and the mean age of AVN diagnosis was 37.6 ± 14.4 years. Both univariate and multivariable logistic regression analyses revealed that a longer disease duration, high LDL-C (low density lipoprotein cholesterol), positive anti-cardiolipin (aCL) IgG and anti-dsDNA results, a history of an oral prednisolone dose of more than 30 mg daily for at least 4 weeks and osteoporotic fractures were significantly associated with AVN. On the other hand, hydroxychloroquin (HCQ), mycophenolate mofetil (MMF) and bisphosphonate use were associated with a lower risk of AVN. No associations with ethnicity were found. In conclusion, several modifiable risk factors were found to be associated with AVN, and these factors may be used to identify patients who are at high risk of developing such complications. The potential protective effects of HCQ, MMF and bisphosphonates warrant additional studies.

Obesity, Chronic Kidney Disease, and Kidney Transplantation: An Evolving Relationship

Obesity has a fundamental role in driving the global kidney disease burden. The perplexing relationship of obesity with chronic kidney disease remains debated. However, a thorough understanding of the interplay of obesity in conjunction with chronic kidney disease and appropriate management options is lacking, leading to further increases in morbidity and mortality. Moreover, underutilization of bariatric procedures and unrealistic expectations of weight reduction based on body mass index, leading to poor access to kidney transplantation, are fueling the fire. In this review, we summarize the available data related to the obesity and chronic kidney disease association and its novel management options.

Factors Affecting Bone Health in Kidney Transplant Recipients: Klotho Gene Single-Nucleotide Polymorphisms and Other Clinical Features

OBJECTIVES

Posttransplant bone diseases are a major cause of morbidity in kidney transplant recipients. We investigated the relationship between klotho gene single-nucleotide polymorphisms and bone diseases after kidney transplant. We also aimed to identify possible risk factors for development of bone disease.

MATERIALS AND METHODS

The study consisted of 251 kidney transplant recipients (164 men and 87 women) with minimum follow-up of 3 years after kidney transplant. Patients with prolonged immobilization, malignancy, parathyroidectomy, glomerular filtration rates less than 30 mL/min/1.73 m², hypo- or hyperthyroidism, and treatment with drugs that affect bone metabolism were excluded. We investigated the relationship between 6 single-nucleotide polymorphisms of the klotho gene (rs480780, rs211234, rs576404, rs211235, rs9536314, and rs1207568) and development of osteoporosis, avascular bone necrosis, and persistent hyperparathyroidism.

RESULTS

Longer dialysis treatment (odds ratio, 1.13; P = .002) and rs211235 single-nucleotide polymorphism in the klotho gene (odds ratio, 9.87; P = .001 for GG genotype) were significantly associated with persistent hyperparathyroidism. A higher magnesium level was detected as a protective factor from development of persistent hyperparathyroidism (odds ratio, 0.19; P = .009). Persistent hyperparathyroidism was defined as a risk factor for development of osteopenia/osteoporosis (odds ratio, 2.76; P = .003) and avascular bone necrosis (odds ratio, 2.52; P= .03). Although the rs480780 (odds ratio, 8.73; P = .04) single-nucleotide polymorphism in the klotho gene was defined as a risk factor for development of osteopenia/osteoporosis, none of the klotho single-nucleotide polymorphisms was found to be associated with development of avascular bone necrosis.

CONCLUSIONS

Persistent hyperparathyroidism could be an important indicator for development of bone disease in kidney transplant recipients. Also, some of the klotho gene single-nucleotide polymorphisms are associated with higher risk for bone disease after kidney transplant.

Incidence and risk factors for osteonecrosis of the hip in renal transplant patients: a prospective single-centre study

BACKGROUND

There is a lack of evidence about the risk factors associated with osteonecrosis of the femoral head (ONFH).

PURPOSES

To determine the incidence and risk factors for ONFH following renal transplantation (RT).

METHODS

In total, data of 681 RT patients (mean age at surgery, 49.5 ± 13.6 years; 249 women and 432 men) were evaluated to determine the incidence of ONFH. Hip magnetic resonance imaging (MRI) was performed six months after RT. The following potential predictors of ONFH were evaluated: (1) patient's condition at RT; laboratory test results including calcium (Ca), phosphorus (P), calcium-phosphorus product (Ca × P), and intact parathyroid hormone before RT; blood relationship between the patient and donor; and mismatching number of human leukocyte antigens (HLAs), especially HLA class I and class II and (2) dosages of steroids after RT, immunosuppressive regimen, and incidence of acute rejection.

RESULTS

ONFH was observed in 30 hips (21 cases, 3.1%). We successfully matched 63 patients without ONFH. Multivariate logistic regression analysis, adjusted for cumulative dosages of steroids, revealed that mismatching number of HLA (hazard ratio [HR], 1.61; 95% confidence interval [CI], 1.10-2.36; p = 0.014), HLA class II (HR, 3.73; 95% CI, 1.46-9.56; p = 0.001), P before RT (HR, 1.62; 95% CI, 1.02-2.58; p = 0.041), and Ca × P  before RT (HR, 1.06; 95% CI, 1.01-1.11; p = 0.024) were risk factors for ONFH.

CONCLUSION

A greater number of HLA mismatches, HLA class II, serum P, and serum Ca × P were risk factors for ONFH after RT. Therefore, these factors should be evaluated in order to predict ONFH after RT.