Secondary Hyperparthyroidism: Pathogenesis, Diagnosis, Preventive and Therapeutic Strategies

Current therapeutic approach of chronic kidney disease-mineral and bone disorder

Chronic kidney disease (CKD) has emerged as one of the leading noncommunicable diseases affecting >10% of the population worldwide. Bone and mineral disorders are a common complication among patients with CKD resulting in a poor life quality, high fracture risk, increased morbidity and cardiovascular mortality. According to Kidney Disease: Improving Global Outcomes, renal osteodystrophy refers to changes in bone morphology found in bone biopsy, whereas CKD-mineral and bone disorder (CKD-MBD) defines a complex of disturbances including biochemical and hormonal alterations, disorders of bone and mineral metabolism and extraskeletal calcification. As a result, the management of CKD-MBD should focus on the aforementioned parameters, including the treatment of hyperphosphatemia, hypocalcemia, abnormal PTH and vitamin D levels. Regarding the bone fragility fractures, osteoporosis and renal osteodystrophy, which constitute the bone component of CKD-MBD, anti-osteoporotic agents constitute the mainstay of treatment. However, a thorough elucidation of the CKD-MBD pathogenesis is crucial for the ideal personalized treatment approach. In this paper, we review the pathology and management of CKD-MBD based on the current literature with special attention to recent advances.

Development and Validation of an Explainable Machine Learning Model for Identification of Hyper-Functioning Parathyroid Glands from High-Frequency Ultrasonographic Images

OBJECTIVE

To develop and validate a machine learning (ML) model based on high-frequency ultrasound (HFUS) images with the aim to identify the functional status of parathyroid glands (PTGs) in secondary hyper-parathyroidism (SHPT) patients.

METHODS

This retrospective study enrolled 60 SHPT patients (27 female, 33 male; mean age: 51.2 years) with 184 PTGs detected from February 2016 to June 2022. All enrollments underwent single-photon emission computed tomography/computed tomography and contrast-enhanced ultrasound examinations. The PTGs were randomly divided into training (n = 147) and testing datasets (n = 37). Four effective ML classifiers were used and combined models incorporating multi-modal HFUS visual signs and radiomics features was constructed based on the optimal classifier. Model performance was compared in terms of discrimination, calibration and clinical utility. The Shapley additive explanation method was used to explain and visualize the main predictors of the optimal model.

RESULTS

This model, using a random forest classifier algorithm, outperformed other classifiers. Based on optimal classifier features, the model constructed from ultrasound visual and ML features achieved a favorable performance in the prediction of hyper-functioning PTGs. Compared with the traditional visual model, the ultrasound-based ML model achieved significant (p = 0.03) improvement (area under the curve: 0.859 vs. 0.629) and higher sensitivity (100.0% vs. 94.1%) and accuracy (86.5% vs. 67.6%). Among the predictors attributed to model development, large size and high echogenic heterogeneity of PTGs in ultrasonographic images were more often associated with high risk of hyper-functioning PTGs.

CONCLUSION

The ultrasound-based ML model for identifying hyper-functioning PTGs in SHPT patients showed good performance and interpretability using high-frequency ultrasonographic images, which may facilitate clinical management.

Management of chronic kidney disease: The current novel and forgotten therapies

Chronic kidney disease (CKD) is a progressive and incurable condition that imposes a significant burden on an aging society. Although the exact prevalence of this disease is unknown, it is estimated to affect at least 800 million people worldwide. Patients with diabetes or hypertension are at a higher risk of developing chronic kidney damage. As the kidneys play a crucial role in vital physiological processes, damage to these organs can disrupt the balance of water and electrolytes, regulation of blood pressure, elimination of toxins, and metabolism of vitamin D. Early diagnosis is paramount to prevent potential complications. Treatment options such as dietary modifications and medications can help slow disease progression. In our narrative review, we have summarized the available therapeutic options to slow the progression of chronic kidney disease. Many new drug treatments have recently become available, offering a beacon of hope and optimism in CKD management. Nonetheless, disease prevention remains the most critical step in disease management. Given the significant impact of CKD on public health, there is a pressing need for further research. With the development of new technologies and advancements in medical knowledge, we hope to find more effective diagnostic tools and treatments for CKD patients.

Identification of key biomarkers based on the proliferation of secondary hyperparathyroidism by bioinformatics analysis and machine learning

Objective

Secondary hyperparathyroidism (SHPT) is a frequent complication of chronic kidney disease (CKD) associated with morbidity and mortality. This study aims to identify potential biomarkers that may be used to predict the progression of SHPT and to elucidate the molecular mechanisms of SHPT pathogenesis at the transcriptome level.

Methods

We analyzed differentially expressed genes (DEGs) between diffuse and nodular parathyroid hyperplasia of SHPT patients from the GSE75886 dataset, and then verified DEG levels with the GSE83421 data file of primary hyperparathyroidism (PHPT) patients. Candidate gene sets were selected by machine learning screens of differential genes and immune cell infiltration was explored with the CIBERSORT algorithm. RcisTarget was used to predict transcription factors, and Cytoscape was used to construct a lncRNA-miRNA-mRNA network to identify possible molecular mechanisms. Immunohistochemistry (IHC) staining and quantitative real-time polymerase chain reaction (qRT-PCR) were used to verify the expression of screened genes in parathyroid tissues of SHPT patients and animal models.

Results

A total of 614 DEGs in GSE75886 were obtained as candidate gene sets for further analysis. Five key genes (USP12, CIDEA, PCOLCE2, CAPZA1, and ACCN2) had significant expression differences between groups and were screened with the best ranking in the machine learning process. These genes were shown to be closely related to immune cell infiltration levels and play important roles in the immune microenvironment. Transcription factor ZBTB6 was identified as the master regulator, alongside multiple other transcription factors. Combined with qPCR and IHC assay of hyperplastic parathyroid tissues from SHPT patients and rats confirm differential expression of USP12, CIDEA, PCOLCE2, CAPZA1, and ACCN2, suggesting that they may play important roles in the proliferation and progression of SHPT.

Conclusion

USP12, CIDEA, PCOLCE2, CAPZA1, and ACCN2 have great potential both as biomarkers and as therapeutic targets in the proliferation of SHPT. These findings suggest novel potential targets and future directions for SHPT research.

Pathophysiology and Clinical Impacts of Chronic Kidney Disease on Coronary Artery Calcification

The global prevalence of chronic kidney disease (CKD) has increased in recent years. Adverse cardiovascular events have become the main cause of life-threatening events in patients with CKD, and vascular calcification is a risk factor for cardiovascular disease. Vascular calcification, especially coronary artery calcification, is more prevalent, severe, rapidly progressive, and harmful in patients with CKD. Some features and risk factors are unique to vascular calcification in patients with CKD; the formation of vascular calcification is not only influenced by the phenotypic transformation of vascular smooth muscle cells, but also by electrolyte and endocrine dysfunction, uremic toxin accumulation, and other novel factors. The study on the mechanism of vascular calcification in patients with renal insufficiency can provide a basis and new target for the prevention and treatment of this disease. This review aims to illustrate the impact of CKD on vascular calcification and to discuss the recent research data on the pathogenesis and factors involved in vascular calcification, mainly focusing on coronary artery calcification, in patients with CKD.

Anaesthetic considerations in Shrinking Man syndrome: two case reports

BACKGROUND

Shrinking Man syndrome (SMS) is a rare but often serious complication of dialysis-dependent end-stage renal disease, characterized by significant loss of height, bone pain, bone deformity, and skin itching. Patients with SMS always have abnormal facial changes and cardiovascular system damage (manifested by hypertension, hypotension, cardiovascular calcification, and valvular heart disease), which pose a great challenge to anaesthesiologists. The purpose of this report is to describe our anaesthetic experience regarding two patients with SMS combined with alterations of the airway and cardiovascular system.

CASE PRESENTATION

We describe two cases of SMS treated at West China Hospital, a tertiary care centre in Chengdu, China. All cases met the diagnostic criteria, which comprised 1) dialysis-dependent end-stage renal disease, 2) loss of height, and 3) bone pain and bone deformity. One patient had an anticipated difficult airway and moderate-to-severe mitral stenosis. The other patient presented with significant hypotension. Anaesthetic considerations included awake fibreoptic bronchoscopy-assisted tracheal intubation, real-time transoesophageal echocardiogram monitoring and individualized blood pressure management strategies.

CONCLUSION

This case series highlights the importance of adequate preoperative assessment and preparation, as well as individualized anaesthetic management, in patients with SMS.

Secondary Hyperparathyroidism Presenting as a Brown Tumor: A Case Report and Review of the Literature

Severe secondary hyperparathyroidism in advanced stages of chronic kidney disease (CKD) is associated with CKD-related mineral and bone disease (CKD-MBD). A 70-year-old woman was admitted at the Hospital for generalized bone pain and peripheral edema. Initial laboratory tests revealed normocytic anemia and severe renal dysfunction, and further tests evidenced severe secondary hyperparathyroidism. Full-body computerized tomography showed an osteolytic lesion in the right iliac wing. The iliac bone lesion was biopsied and histological examination was consistent with the diagnosis of a brown tumor of hyperparathyroidism. Brown tumors are a rare variant of osteitis fibrosa cystica that results from sustained high levels of parathyroid hormone in CKD. This case sheds light on rare complications that are experienced today in CKD. The clinical and biochemical setting, as well as the clinical suspicion, are essential to the diagnosis.

Hyperparathyroidism in a Large Cohort of Chinese Patients with Tumor-Induced Osteomalacia

CONTEXT

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by excessive production of fibroblast growth factor 23 (FGF23) by a tumor. Hyperparathyroidism (HPT) including secondary HPT (SHPT) and tertiary HPT (THPT) in TIO patients, which is considered to associate with phosphate supplementation, has not been well documented.

OBJECTIVES

To clarify the prevalence, clinical characteristics, and risk factors for HPT in a large cohort of Chinese TIO patients in our hospital.

DESIGN, SETTING AND PARTICIPANTS

This retrospective study enrolled 202 TIO patients.

MAIN OUTCOME MEASUREMENTS

Occurrence of HPT in TIO patients.

RESULTS

HPT was observed in 91 patients (91/202, 45.1%), as 84 patients (41.6%) were diagnosed as SHPT and seven patients (3.5%) were diagnosed as THPT. All patients with THPT underwent parathyroidectomy and only one patient experienced recurrence. Compared with patients without HPT, patients with SHPT had longer disease duration, higher rate of phosphate and calcitriol supplementation, lower serum calcium, lower urine calcium excretion, and higher urine phosphate excretion. Compared with patients with SHPT, patients with THPT had even longer disease duration, higher rate of phosphate and calcitriol supplementation. PTH levels showed positive correlation with intact FGF23 and 1,25(OH)2D levels, but not 25OHD level in TIO patients. Multivariate logistic regression analysis showed that long disease duration and phosphate supplementation were independently associated with occurrence of HPT in TIO patients. Further logistic regression analysis and restricted cubic spline model revealed dose-response relationship between cumulative dose of phosphate supplementation and PTH levels.

CONCLUSIONS

HPT is common in our TIO patients. To avoid the occurrence of HPT in TIO patients, timely diagnosis and tumor resection is necessary, and excessive dose of phosphate supplementation is not suggested before surgery.

[Reoperation treatment of persistent postoperative secondary hyperparathyroidism]

Objective:To evaluate the clinical effect of reoperation in persistent hyperparathyroidism （PHPT） patients after operation of parathyroidectomy combined with autotransplantation（PTX+AT） on secondary hyperparathyroidism （SHPT） . Methods:18 PHPT patients who treated with reoperation after PTX+AT were enrolled in this study during the period from Aug 2012 to Dec 2021 in the Department of Otolaryngology Head and Neck Surgery of Peking University Civil Aviation School of Clinical Medicine, Civil Aviation General Hospital. The remaining parathyroid glands were located by preoperative colour Doppler ultrasonography, radionuclide imaging, enhanced CT and MR imaging in the neck region . Based on the imaging findings, the remaining parathyroid glands were removed in situ, and the missed ectopic or extra parathyroid glands were resected with an extended surgical scope according to the parathyroid dissection method. The surgical effect was evaluated by the changes of clinical symptoms, the dynamic change of serum intact paramyroidhomone（i-PTH） between preoperative and postoperative periods and the surgical complications. Results:All the 18 patients accepted successful operation. 30 parathyroid glands were resected confirmed by postoperative pathology, including 16 in situ and 14 ectopic glands（5 in superior mediastinum, 4 in thymus, 2 in posterior mediastinum ,2 in thyroid glands, 1 in carotid sheath）.Osteoarthropathy and skin itching were significantly relieved or even disappeared at 6 h after surgery. The levels of serum i-PTH, calcium and phosphorus reached the standards and muscle weakness was significantly improved 1 week after surgery. 16 patients presented hypocalcemia and returned to normal after supplement of calcium. Hoarseness due to temporary injury of laryngeal nerve was found in 6 cases. No serious complications or death occurred after the operation.There was no recurrence after 1 year follow-up. Conclusion:Reoperation is the first choice for SHPT patients complicated with persistent hyperparathyroidism. Multiple imaging examinations are used to locate the residual parathyroid, especially the ectopic gland. Expanded surgical scope is applied to resect all the residual parathyroid glands（ectopic, in situ and concealed parathyroid） according to the concept of dissection parathyroidectomy. The surgery is effective and safe. Patients'quality of life and long-term survival rate is improved.

Correlation Decomposition between TCM Syndrome Types and Calcium and Phosphorus Metabolism in 50 Maintenance Hemodialysis Sufferers

Aiming to reveal the relationship between TCM syndrome types and calcium and phosphorus metabolism in maintenance hemodialysis (MHD) sufferers, 50 sufferers diagnosed with MHD who were admitted to Suixi County Hospital in Anhui Province are selected for retrospective decomposition. The data of TCM classification and laboratory indicators of the sufferers are collected. The experimental results indicate that calcium and phosphorus metabolism disorder is common in maintenance hemodialysis patients, especially calcium and phosphorus product and blood phosphorus elevation. The increase of the calcium-phosphorus product is closely related to the mortality and calcification rate of the subcutaneous soft tissue. It can provide a reference for the diagnosis and therapy of abnormal calcium and phosphorus metabolism in sufferers, which is worthy of clinical application.

A roadmap to parathyroidectomy for kidney transplant candidates

Chronic kidney disease mineral and bone disorder may persist after successful kidney transplantation. Persistent hyperparathyroidism has been identified in up to 80% of patients throughout the first year after kidney transplantation. International guidelines lack strict recommendations about the management of persistent hyperparathyroidism. However, it is associated with adverse graft and patient outcomes, including higher fracture risk and an increased risk of all-cause mortality and allograft loss. Secondary hyperparathyroidism may be treated medically (vitamin D, phosphate binders and calcimimetics) or surgically (parathyroidectomy). Guideline recommendations suggest medical therapy first but do not clarify optimal parathyroid hormone targets or indications and timing of parathyroidectomy. There are no clear guidelines or long-term studies about the impact of hyperparathyroidism therapy. Parathyroidectomy is more effective than medical treatment, although it is associated with increased short-term risks. Ideally parathyroidectomy should be performed before kidney transplantation to prevent persistent hyperparathyroidism and improve graft outcomes. We now propose a roadmap for the management of secondary hyperparathyroidism in patients eligible for kidney transplantation that includes the indications and timing (pre- or post-kidney transplantation) of parathyroidectomy, the evaluation of parathyroid gland size and the integration of parathyroid gland size in the decision-making process by a multidisciplinary team of nephrologists, radiologists and surgeons.

Case report: Reoperative parathyroidectomy for large ectopic hyperplastic parathyroid in the mediastinum of a patient with recurrent secondary hyperparathyroidism

Introduction

Secondary hyperparathyroidism (SHPT) is a common complication in hemodialysis patients with chronic renal failure uremia. For severe SHPT, parathyroidectomy is effective. Owing to the variability in parathyroid anatomy, surgical parathyroidectomy can be complex and many patients experience recurrent SHPT, which may require repeated surgery. These cases pose significant challenges to surgeons.

Case description

An elderly woman with recurrent severe SHPT was admitted to our hospital. Preoperative methoxyisobutylisonitrile (MIBI) examination found a large ectopic parathyroid gland in the superior mediastinum, and she underwent reoperative parathyroidectomy. A large parathyroid gland in the right anterior mediastinum and another parathyroid gland in the left lingual lobe of the thymus were removed. The patient had postoperative hypocalcemia that was successfully corrected with calcium supplementation via femoral vein catheterization. During the 1-year postoperative follow-up, the patient's iPTH was well controlled and her blood calcium was within the normal range.

Conclusion

We report a case of parathyroidectomy to remove multifocal ectopic hyperplastic parathyroid tissue in the mediastinum. Preoperative MIBI accurately detected the lesions. Calcium supplementation via femoral vein catheterization successfully corrected postoperative hypocalcemia. Postoperative follow-up for 1 year indicated that the surgery was successful.

Serum Phosphorus, Parathyroid Hormone, and Serum Fibroblast Growth Factor-23 in Egyptian Patients Six Months after Undergoing Living-donor Kidney Transplantation

End-stage renal disease is a major health problem with many complications. Previous studies emphasized the relationship of cardiovascular disease and mortality among these patients to dysregulated phosphate homeostasis. Even after successful renal transplantation, the risk is not eliminated. Several factors seem to interplay to regulate serum phosphorus levels after renal transplantation. Fibroblast growth factor-23 (FGF-23) is a hormone with the major function of inhibiting the reabsorption of phosphate by the renal tubules. Parathormone reduces the reabsorption of phosphate from the proximal tubule of the kidney. The aim of our study was to explore the changes that occurred in FGF-23 and intact parathyroid hormone (iPTH) levels in a cohort of Egyptian patients undergoing renal transplantation and to examine the effect of these factors on posttransplant serum phosphorus levels. The study was carried out prospectively on 37 candidates for live-donor renal transplantation. Serum levels of calcium, phosphorus, iPTH, and FGF-23 were measured before and 6 months after renal transplantation. Statistically significant differences were detected in serum calcium, phosphorus, FGF-23, and iPTH before and 6 months after transplantation (P < 0.001, P < 0.001, P < 0.001, and P < 0.001, respectively). The results also showed a statistically significant correlation between FGF-23 levels and phosphorus levels before transplantation. The interplay between FGF-23 and iPTH has an impact on posttransplant serum phosphorus levels.

Ultrasound-guided thermal ablation for hyperparathyroidism: current status and prospects

BACKGROUND

Hyperparathyroidism (HPT) is classified into primary HPT (PHPT), secondary HPT (SHPT), tertiary HPT (THPT), and pseudohyperparathyroidism. Parathyroid surgery is generally reserved for patients with symptomatic PHPT and asymptomatic patients who meet the surgical guideline criteria. However, the risk of complications and mortality after parathyroid gland surgery increases with increasing patient age.

AIM

This study aimed to review existing research on laser ablation, radiofrequency ablation, microwave ablation, and high-intensity focused ultrasound in the treatment of HPT and analyze its application prospects.

CONCLUSIONS

Thermal ablation is a good alternative treatment for patients with parathyroid hyperplasia who do not meet the criteria or decline surgery. Being a type of minimally invasive treatment, ultrasound-guided thermal ablation has the advantages of easy operation, rapid recovery, and reusability and is used widely.

Modern problems of hyper- and hypoparathyroidism

The parathyroid glands are the most important regulators of mineral metabolism. The parathyroid glands were first discovered only in 1880 and their function went the long way unrecognized. Even the term "parathyroid gland" itself speaks of the initial misconception of it as an underdeveloped part of the thyroid. To date, there is a large amount of data regarding the role of this endocrine gland in the human body and the significant changes associated with their dysfunction, including such widespread diseases such primary, secondary and tertiary hyperparathyroidism, hypoparathyroidism. This review covers the problem of the main disturbances in calcium-phosphorus metabolism, presents the results of databases of patients with primary hyperparathyroidism and hypoparathyroidism, as well as current epidemiological trends in Russia and in the world.

Use of 99mTc-sestamibi SPECT/CT imaging in predicting the degree of pathological hyperplasia of the parathyroid gland: semi-quantitative analysis

Background

Previous studies have demonstrated that ^99mTc-sestamibi (^99mTc-MIBI) Single-Photon Emission Computed Tomography/ Computed Tomography (SPECT/CT) imaging is an effective isotopic technique for locating the parathyroid in secondary hyperparathyroidism (SHPT). This study aimed to explore further the correlation between ^99mTc-MIBI SPECT/CT imaging and SHPT to demonstrate the value of ^99mTc-MIBI SPECT/CT in evaluating the degree of pathological hyperplasia of the parathyroid gland (PG).

Methods

The demographics, surgical records, and follow-up information of 91 patients were recorded and analyzed. A total of 216 paraffin-embedded PGs of 54 patients were obtained and analyzed.

Results

Patients with ^99mTc-MIBI negative PG(s) had significantly lower preoperative serum phosphorus and higher serum calcium levels at 6 months postoperatively compared to those with ^99mTc-MIBI positive PG(s) (P<0.05). We also found a higher total uptake ratio of the region of interest (URRI) and higher URRI max in the hypocalcemia group than in the non-hypocalcemia group. Both URRI total (P=0.003) and URRI max (P=0.028) were independent risk factors for hypocalcemia 6 months postoperatively. The URRI values of the PGs were significantly positively correlated with glandular weight (R²=0.343, P<0.001), glandular volume (R²=0.240, P<0.001), and degree of pathological hyperplasia (P<0.001). However, the URRI value of the PGs exhibited a notably weak correlation with proliferating cell nuclear antigen (PCNA) (R²=0.035, P=0.006). The area under the receiver operating characteristic curve showed a URRI evaluative value of 0.771 for diffuse and nodular types in 216 PGs (P<0.001). We further evaluated 167 nodular-type PGs, distinguishing between nodular hyperplasia and a single nodule; the URRI evaluative value reached 0.819, which was higher than the volume or weight (P<0.001).

Conclusions

The ^99mTc-MIBI SPECT/CT scintigraphy results were related to serum calcium levels at 6 months after total parathyroidectomy with autotransplantation (TPTX+AT), suggesting the occurrence of hypocalcemia (6 months after TPTX+AT). More importantly, this technique effectively evaluated the pathological hyperplasia of PGs preoperatively, and therefore, could assist surgeons in selecting the PGs with the lowest degree of hyperplasia intraoperatively.

Torus Mandibularis in Patients Receiving Hemodialysis

Reports on the prevalence of torus mandibularis among dialysis patients have been limited and inconclusive. A wide variety of oral manifestations has been found in patients with hyperparathyroidism. Furthermore, uremia-related changes in facial bone structures have been described in the literature. This prospective observational study examined 322 hemodialysis patients treated at the Chang Gung Memorial Hospital from 1 August to 31 December 2016. Two subgroups were identified: patients with torus mandibularis (n = 25) and those without (n = 297). Clinical oral examinations including inspection and palpation were employed. Our study found that most mandibular tori were symmetric (84.0%), nodular (96.0%), less than 2 cm in size (96.0%), and located in the premolar area (92.0%). Poor oral hygiene was observed among these patients, with 49.7% and 24.5% scoring 3 and 4, respectively, on the Quigley-Hein plaque index. More than half (55.0%) of patients lost their first molars. Multivariate logistic regression analysis revealed that blood phosphate level (odds ratio = 1.494, p = 0.029) and younger age (odds ratio = 0.954, p = 0.009) correlated significantly with torus mandibularis. The prevalence of torus mandibularis in patients receiving hemodialysis in this study was 7.8%. Younger age and a higher blood phosphate level were predictors for torus mandibularis in these patients.

Hiperparatiroidismo primario: conceptos para el cirujano general

Durante las últimas décadas, la incidencia del hiperparatiroidismo primario ha venido en aumento, muy probablemente relacionado con la mayor accesibilidad a los estudios diagnósticos; sin embargo, la forma más común de presentación clínica del hiperparatiroidismo primario es asintomática, en más del 80% de los pacientes. En la actualidad, es menos frecuente el diagnóstico por las complicaciones renales (urolitiasis) u óseas (osteítis fibrosa quística) asociadas. Un tumor benigno de la glándula paratiroides (adenoma único), es la principal causa de esta enfermedad. Por tanto, su tratamiento usualmente es quirúrgico. A pesar de ello, no es frecuente el manejo de esta patología por el cirujano general. En este artículo se revisan conceptos claves para el diagnóstico y manejo de esta enfermedad para el médico residente y especialista en Cirugía general.

Mechanisms of Bone Remodeling Disorder in Hemophilia

Hemophilia is caused by a lack of antihemophilic factor(s), for example, factor VIII (FVIII; hemophilia A) and factor IX (FIX; hemophilia B). Low bone mass is widely reported in epidemiological studies of hemophilia, and patients with hemophilia are at an increased risk of fracture. The detailed etiology of bone homeostasis imbalance in hemophilia is unclear. Clinical and experimental studies show that FVIII and FIX are involved in bone remodeling. However, it is likely that antihemophilic factors affect bone biology through thrombin pathways rather than via their own intrinsic properties. In addition, among patients with hemophilia, there are pathophysiological processes in several systems that might contribute to bone loss. This review summarizes studies on the association between hemophilia and bone remodeling, and might shed light on the challenges facing the care and prevention of osteoporosis and fracture in patients with hemophilia.

Vitamin D Metabolism and Its Role in Mineral and Bone Disorders in Chronic Kidney Disease in Humans, Dogs and Cats

Some differences regarding Vitamin D metabolism are described in dogs and cats in comparison with humans, which may be explained by an evolutionary drive among these species. Similarly, vitamin D is one of the most important regulators of mineral metabolism in dogs and cats, as well as in humans. Mineral metabolism is intrinsically related to bone metabolism, thus disturbances in vitamin D have been implicated in the development of chronic kidney disease mineral and bone disorders (CKD-MBD) in people, in addition to dogs and cats. Vitamin D deficiency may be associated with Renal Secondary Hyperparathyroidism (RSHPT), which is the most common mineral disorder in later stages of CKD in dogs and cats. Herein, we review the peculiarities of vitamin D metabolism in these species in comparison with humans, and the role of vitamin D disturbances in the development of CKD-MBD among dogs, cats, and people. Comparative studies may offer some evidence to help further research about vitamin D metabolism and bone disorders in CKD.

Calcium-mediated parathyroid hormone suppression test in uraemic secondary hyperparathyroidism

AIM

The present study aimed to investigate the value of calcium-mediated parathyroid hormone (PTH) suppression test in evaluating the autonomic secretory function of parathyroid, and the management of uraemic secondary hyperparathyroidism (SHPT).

METHODS

Calcium-mediated PTH suppression test was performed in dialysis with SHPT, who were candidates for parathyroidectomy from June 2017 to December 2019 in our hospital. The PTH inhibition rate (PTH-IR) was calculated, and the correlation between PTH-IR and clinical indicators was explored.

RESULTS

Fifty-one subjects were included. PTH-IR was negatively correlated with baseline PTH (r = -0.35, P = .012), it was also correlated with dialysis years, coronary artery calcification score (CACS) and parathyroid mass (r = -0.397, P = .004; r = -0.327, P = .028; r = -0.363, P = .015), which were not found for baseline PTH. Forty-four patients underwent surgical treatment. According to the histological results, 26 patients presented with parathyroid non-nodular hyperplasia, and 18 patients presented with parathyroid nodular hyperplasia. The mass of parathyroid of patients with nodular hyperplasia was higher than that of patients with non-nodular hyperplasia (ρ = 0.01). The difference of the PTH-IR was not found between the two groups (ρ = 0.296). During the test, the highest serum calcium was 2.9 ± 0.4 mmol/L, which dropped to normal at the end of the test.

CONCLUSION

Parathyroid hormone inhibition rate might be a useful indicator in evaluating the autonomic secretory function of parathyroid and the progression of SHPT on top of intact PTH. Calcium-mediated PTH suppression test was safe in uraemic SHPT patients, but need to monitor for transient hypercalcaemia.

Recent advances in understanding and managing secondary hyperparathyroidism in chronic kidney disease

Secondary hyperparathyroidism is a complex pathology that develops as chronic kidney disease progresses. The retention of phosphorus and the reductions in calcium and vitamin D levels stimulate the synthesis and secretion of parathyroid hormone as well as the proliferation rate of parathyroid cells. Parathyroid growth is initially diffuse but it becomes nodular as the disease progresses, making the gland less susceptible to be inhibited. Although the mechanisms underlying the pathophysiology of secondary hyperparathyroidism are well known, new evidence has shed light on unknown aspects of the deregulation of parathyroid function. Secondary hyperparathyroidism is an important feature of chronic kidney disease-mineral and bone disorder and plays an important role in the development of bone disease and vascular calcification. Thus, part of the management of chronic kidney disease relies on maintaining acceptable levels of mineral metabolism parameters in an attempt to slow down or prevent the development of secondary hyperparathyroidism. Here, we will also review the latest evidence regarding several aspects of the clinical and surgical management of secondary hyperparathyroidism.

Seasonal variation and correlation analysis of vitamin D and parathyroid hormone in Hangzhou, Southeast China

This study aimed to describe the 25‐hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) status of Southeast Chinese individuals influenced by season. The secondary aim was to determine the cutoff for sufficient 25(OH)D in a four‐season region. From January 2011 to June 2014, a total of 17 646 individuals were evaluated in our study. The serum levels of PTH were detected simultaneously in 5579 cases. A total of 25(OH)D and intact PTH were measured by the electrochemiluminescent immunoassay. The distribution of the concentration, prevalence and seasonal variability of 25(OH)D and PTH were studied. The mean 25(OH)D concentration in our study was 43.00(30.40) nmol/L. The prevalence of insufficiency (25(OH)D < 50 nmol/L) was 62.87% and that of deficiency (<30 nmol/L) was 28.54%. Mean serum 25(OH)D levels revealed a limited sinusoidal profile throughout the year and were significantly higher in Autumn. On the other hand, PTH levels showed an opposite response to seasonal effects relative to 25(OH)D. Age, BMI and daylight were not significantly correlated with 25(OH)D and serum PTH reached a plateau at higher values of serum 25(OH)D of 42.86 nmol/L. This study demonstrated that Vitamin D insufficiency is highly prevalent in Southeast China. The concentration of 25(OH)D in the male group was generally higher than that in the female group. Seasonal variation was an important aspect of 25(OH)D and PTH concentration. This study revealed that the optimal serum threshold of 25(OH)D for bone health should be between 40 and 50 nmol/L for Southeast Chinese individuals.

Torus Palatinus in Taiwan Patients Receiving Peritoneal Dialysis and Hemodialysis: A Prospective Observational Study

Purpose

A consensus about the pathogenesis of torus palatinus (TP) in patients receiving dialysis still eludes the scientific community. This prospective observational study investigated the epidemiology of TP in peritoneal dialysis and hemodialysis patients and analyzed the influences of multiple pathogenic factors such as mineral and bone disorders, genetic, environmental or nutritional triggers, progression of age, heredity, climatologic or biomechanical causes, and hyperparathyroidism on the formation of TP.

Methods

Between 2013 and 2016, a total of 575 chronic dialysis patients (441 on hemodialysis and 134 on peritoneal dialysis) were recruited from Chang Gung Memorial Hospital, Taiwan. Patients were stratified into two groups based on the presence (n = 179) or absence (n = 396) of TP. Demographic, oral examination, laboratory, and dialysis data were collected for analysis. Student’s t-test was used to analyze the quantitative variables and Chi-square or Fisher’s exact test for categorical variables. Univariate binary logistic regression analysis was conducted to determine the predictors for TP and multivariate binary logistic regression analysis to identify significant associated factors.

Results

The prevalence of TP in dialysis patients in this study was 31.1% (28.3% for hemodialysis and 40.3% for peritoneal dialysis). Patients with TP were younger (54.6 ± 13.4 versus 58.9 ± 14.7 years, P = 0.001) and mostly female (60.3 versus 41.2%, P < 0.001). Most TP cases (55.3%) were small in size (<2 cm), with the flat shape (56.4%) being the most common followed by the spindle (17.9%), nodular (17.3%), and lobular (8.4%) shapes. A longer duration of dialysis was associated with TP ≥2 cm than with TP <2 cm (94.4 ± 85.9 versus 72.8 ± 59.1 months, P = 0.048). Multivariate logistic regression revealed that female gender (odds ratio 2.108, 95% confidence interval 1.455–3.055, P < 0.001) and younger age (odds ratio 0.982; 95% confidence interval 0.969–0.994, P = 0.005) were significant predictors for TP.

Conclusion

The prevalence of TP in chronic dialysis patients is 31.1%, higher in patients receiving peritoneal dialysis (40.3%) than hemodialysis (28.3%). Female gender and younger age are significant predictors associated with TP.

Epidemiology and management of parathyroid gland disorders in Spain over 15 years: A retrospective multicentre analysis

Parathyroid gland disorders are rare conditions with an incidence that displays great variability among populations. Its direct influence in calcium homeostasis originates variable symptoms that affect bone remodelling among other processes. This study aimed to provide data on the epidemiology and characteristics of patients admitted with these disorders in Spain between 2003 and 2017, and to analyse disease management and direct medical costs. Medical records in which a disorder of the parathyroid gland was registered as the admission motive were extracted from a nationwide hospital-discharge database via the Spanish Ministry of Health. Records from 12,903 patients were obtained, with predominance of female patients (74.70%) and of admissions due to hyperparathyroidism (90.23%). The number of patients admitted per year increased over the study period along the incidence of these disorders. The year 2017 incidence of hyperparathyroidism was 2.95 per 10,000, 4.03 per 10,000 in females and 1.37 in males; the same year, the incidence of hypoparathyroidism was 0.17 per 10,000. Length of hospital stay was significantly extended in patients with hypoparathyroidism (7.16 days), admitted mostly due to emergencies. Heart failure was diagnosed in more than 20% of admissions in patients with secondary and tertiary hyperparathyroidism and hypoparathyroidism, while this last group displayed the highest levels of mineral metabolism disruption. Parathyroidectomy was performed in 78.95% of all admissions for primary hyperparathyroidism. The total annual direct medical cost parathyroid gland disorders has increased over the study period, due to the increase of the costs associated to hyperparathyroidism, whereas the cost per patient remained relatively stable, with an average of €3,748, €3,430 and €3,737 for patients with hyperparathyroidism, hypoparathyroidism and other disorders of the parathyroid gland, respectively. This study provides novel data to extend the scarce available knowledge on parathyroid gland disorders’ epidemiology and management in Spain.

Evaluation of laboratory parameters and symptoms after parathyroidectomy in dialysis patients with secondary hyperparathyroidism

Objectives: The aim of the study was to evaluate the laboratory parameters and symptoms after parathyroidectomy (PTX) in dialysis patients with secondary hyperparathyroidism (SHPT), and to briefly analyze the different therapeutic effects of the three surgical methods.

Methods: A total of 182 dialysis patients who underwent PTX between February 2012 and January 2018 at the Second Affiliated Hospital of Soochow University were included in this study and followed for 12 months. Laboratory parameters such as calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), and intact parathyroid hormone (iPTH) were measured before and after operation. According to the follow-up time and type of operation, we calculated the percentage of laboratory indicators reaching the recommended range of the KDIGO guidelines after surgery. We also analyzed the improvement of bone pain and pruritus, as well as surgical complications.

Results: After the operation, the levels of iPTH, Ca, and P decreased significantly at each time point. ALP increased at the first postoperative week and gradually decreased to normal range after 3 months. Symptoms, such as bone pain and pruritus, were significantly relieved. According to the follow-up time and three surgical methods (subtotal parathyroidectomy, total parathyroidectomy, total parathyroidectomy plus autologous transplantation), we found that the ratio of each laboratory parameter reaching the recommended range of KDIGO guidelines was significantly different.

Conclusion: PTX is a safe and effective therapy for treating SHPT that is refractory to medical therapies and accompanied by related signs and symptoms in dialysis patients. All three operative techniques were effective in controlling SHPT.

PTH induces bone loss via microbial-dependent expansion of intestinal TNF+ T cells and Th17 cells

Bone loss is a frequent but not universal complication of hyperparathyroidism. Using antibiotic-treated or germ-free mice, we show that parathyroid hormone (PTH) only caused bone loss in mice whose microbiota was enriched by the Th17 cell-inducing taxa segmented filamentous bacteria (SFB). SFB⁺ microbiota enabled PTH to expand intestinal TNF⁺ T and Th17 cells and increase their S1P-receptor-1 mediated egress from the intestine and recruitment to the bone marrow (BM) that causes bone loss. CXCR3-mediated TNF⁺ T cell homing to the BM upregulated the Th17 chemoattractant CCL20, which recruited Th17 cells to the BM. This study reveals mechanisms for microbiota-mediated gut-bone crosstalk in mice models of hyperparathyroidism that may help predict its clinical course. Targeting the gut microbiota or T cell migration may represent therapeutic strategies for hyperparathyroidism.

Calcium citrate: from biochemistry and physiology to clinical applications

Adequate daily calcium intake should normally be achieved by dietary sources. Since low calcium diets are quite common in subjects that do not reach the recommended intake and particularly those at risk of fractures, calcium supplements may become necessary. Different forms of calcium salts are available, but products containing calcium citrate and calcium carbonate complexes are the most frequently used. Although only limited evidence on the efficacy and long-term safety of calcium citrate is available, these supplements may represent a valuable product for the management of different chronic pathological conditions. The aim of this review was to evaluate the current and potential clinical applications of calcium citrate. In particular, we focused on the use of calcium citrate supplementation in subjects with osteoporosis or in bariatric patients. Other pathological conditions that could benefit calcium citrate supplementation may include achloridria, chronic hypoparathyroidism and hypocitraturic subjects with moderate/high risk of nephrolithiasis. Indeed, citrate salts are widely used in the treatment of nephrolithiasis, since they have shown an inhibitory effect on kidney stone formation and recurrence.

Phosphorus Counting Table for the control of serum phosphorus levels without phosphate binders in hemodialysis patients

BACKGROUND AND AIMS

Hyperphosphatemia constitutes one of the major problems faced by patients with chronic kidney disease, and nourishment plays a significant role in its control. The present study aimed to evaluate the maintenance of phosphorus serum levels by observing measurements before and after an intervention using the Phosphorus Counting Table (PCT), in hemodialysis patients lacking phosphate binder use.

METHODS

The assessment included fifty individuals on hemodialysis who underwent phosphate binder suspension 30 days prior to the intervention. The participants received food and nutrition education on the PCT tool, which assists in the control of dietary phosphorus intake, and followed its instructions for two months. Fasting blood samples were collected at three moments for phosphorus, total calcium, and parathyroid hormone (PTH) analysis. The study sample was initially analyzed as a whole, then sub-classified into two groups: adherence and non-adherence.

RESULTS

At the end of the study, no significant difference in serum phosphorus was observed in the total and the adherence groups (p > 0.05). The non-adherence group showed a substantial increase of 0.74 mg/dL in serum phosphorus levels and 6.16 mg²/dL² in the calcium-phosphorus product after the intervention. Meanwhile, the calcium-phosphorus product improved from 56.42 ± 11.49 mg²/dL² to 51.05 ± 10.67 mg²/dL² in the adherence group. Serum calcium levels did not change throughout the study in the three groups. A significant increment in PTH serum levels was observed at the end of the study in all groups.

CONCLUSION

The PCT showed to be efficient in the maintenance of serum phosphorus in the individuals who adhered well to the tool, without the administration of phosphate binders. Such a method can assist in patient adherence to treatment and enables better diet flexibility. The present trial was registered under the Brazilian Clinical Trials Registry (Rebec). Registration number: RBR-2vzd48.

Effects of parathyroidectomy on the biology of bone tissue in patients with chronic kidney disease and secondary hyperparathyroidism

Secondary hyperparathyroidism is a complication of chronic kidney disease that compromises skeletal integrity. In patients with secondary hyperparathyroidism undergoing parathyroidectomy, parathyroid hormone levels dramatically decrease. The effects of parathyroidectomy on bone tissue are poorly understood, especially regarding the proteins expressed by osteocytes, such as fibroblast growth factor 23, dentin matrix protein 1, matrix extracellular phosphoglycoprotein, sclerostin, receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin, which regulate bone turnover. The objective of this study was to characterize the bone expression of these proteins by immunohistochemistry and correlate these results with those of bone histomorphometry before and after parathyroidectomy. We studied bone biopsies that were obtained from 23 patients before and 12 months after parathyroidectomy. We observed an improvement in bone microarchitecture, but impaired mineralization after parathyroidectomy. We found significant increases in sclerostin and osteoprotegerin expression and a decrease in the RANKL/osteoprotegerin ratio after parathyroidectomy, suggesting that their expression is regulated by parathormone. These proteins correlated with structural and bone formation parameters. We conclude that after parathyroidectomy, significant changes occur in the bone expression of osteocyte proteins and that these proteins potentially regulate bone remodeling.

FGF23, Biomarker or Target?

Fibroblast growth factor 23 (FGF23) plays a key role in the complex network between the bones and other organs. Initially, it was thought that FGF23 exclusively regulated phosphate and vitamin D metabolism; however, recent research has demonstrated that an excess of FGF23 has other effects that may be detrimental in some cases. The understanding of the signaling pathways through which FGF23 acts in different organs is crucial to develop strategies aiming to prevent the negative effects associated with high FGF23 levels. FGF23 has been described to have effects on the heart, promoting left ventricular hypertrophy (LVH); the liver, leading to production of inflammatory cytokines; the bones, inhibiting mineralization; and the bone marrow, by reducing the production of erythropoietin (EPO). The identification of FGF23 receptors will play a remarkable role in future research since its selective blockade might reduce the adverse effects of FGF23. Patients with chronic kidney disease (CKD) have very high levels of FGF23 and may be the population suffering from the most adverse FGF23-related effects. The general population, as well as kidney transplant recipients, may also be affected by high FGF23. Whether the association between FGF23 and clinical events is causal or casual remains controversial. The hypothesis that FGF23 could be considered a therapeutic target is gaining relevance and may become a promising field of investigation in the future.

Active Vitamin D in Chronic Kidney Disease: Getting Right Back Where We Started from?

BACKGROUND

The vitamin D system is essential for optimal health in humans. Circulating calcitriol, a key metabolite in maintaining calcium and phosphorus homeostasis, is produced in the kidney. In kidney failure, calcitriol levels progressively decrease, contributing to the development of renal secondary hyperparathyroidism (SHPT).

SUMMARY

For years, SHPT had a central role in the disturbed mineral metabolism of renal patients. As calcitriol deficiency contributes to SHPT development, treatment with calcitriol or other compounds able to activate the vitamin D receptor (VDR) was one of the mainstays of therapy for renal patients in the last 40 years. In this review, we discuss how the treatment with VDR activators (VDRA) evolved during this time in the United States, as well as the main factors responsible for these changes.

KEY MESSAGES

Management of SHPT with VDRA in renal patients has undergone a few paradigm shifts over the last 40 years. When treating SHPT, the newly developed therapies as well as VDRA need to be carefully considered and used appropriately. Nephrologists need to use an integrated approach that avoids excessive use of VDRA, ensures replenishment of vitamin D stores, and avoids hypercalcemia and hyperphosphatemia.

Survey of Torus Palatinus in Patients with End-Stage Renal Disease Undergoing Hemodialysis

Introduction

This study attempted to survey the oral findings of hemodialysis patients and analyze the prevalence and predictors for torus palatinus (TP) in this patient population.

Methods

A total of 322 hemodialysis patients were recruited. Patients were organized into two groups, based on the presence (n=93) or absence (n=229) of TP. Demographic, laboratory, and dialysis-related data were obtained for analysis.

Results

The prevalence of TP was 28.9% in this study. Patients with TP were younger in age [57.8±10.0 (37.4-86.9) versus 62.4±12.3 (25.0-87.8) years old; P=0.001] and predominantly female (60.2% versus 38.0%; P<0.001), compared to patients without TP. All TPs (100.0%) were symmetrical and located along the midpalatal suture. Most TPs were flat-shaped (55.9%) and near premolars (78.5%). The blood tests revealed higher blood concentrations of phosphate (5.4±1.1 versus 4.9±1.1 mg/dL; P=0.001) and lower blood concentrations of bicarbonate (20.9±2.4 versus 22.0±2.3 mmol/L; P<0.001) in patients with TP. Multivariate regression modeling showed that younger age [odds ratio (OR) 0.968; 95% confidence interval (CI) 0.939–0.982; P<0.001], female gender (OR 2.305; 95% CI 1.374–3.867; P=0.002), higher blood concentration of phosphate (OR 1.411; 95% CI 1.110–1.794; P=0.005), and lower blood concentration of bicarbonate (OR 0.868; 95% CI 0.791–0.994; P=0.040) were significant predictors for TP.

Conclusion

The prevalence of TP is 28.9%, and the majority of patients suffering TP are female. Younger age, female gender, elevated blood concentration of phosphate, and lower blood concentration of bicarbonate are predictors for TP.

Parathyroid Hormone Fragments: New Targets for the Diagnosis and Treatment of Chronic Kidney Disease-Mineral and Bone Disorder

As a common disorder, chronic kidney disease (CKD) poses a great threat to human health. Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a complication of CKD characterized by disturbances in the levels of calcium, phosphorus, parathyroid hormone (PTH), and vitamin D; abnormal bone formation affecting the mineralization and linear growth of bone; and vascular and soft tissue calcification. PTH reflects the function of the parathyroid gland and also takes part in the metabolism of minerals. The accurate measurement of PTH plays a vital role in the clinical diagnosis, treatment, and prognosis of patients with secondary hyperparathyroidism (SHPT). Previous studies have shown that there are different fragments of PTH in the body's circulation, causing antagonistic effects on bone and the kidney. Here we review the metabolism of PTH fragments; the progress being made in PTH measurement assays; the effects of PTH fragments on bone, kidney, and the cardiovascular system in CKD; and the predictive value of PTH measurement in assessing the effectiveness of parathyroidectomy (PTX). We hope that this review will help to clarify the value of accurate PTH measurements in CKD-MBD and promote the further development of multidisciplinary diagnosis and treatment.

Pulse versus daily oral Alfacalcidol treatment of secondary hyperparathyroidism in hemodialysis patients: a randomized controlled trial

BACKGROUND

Secondary hyperparathyroidism is a common complication of chronic kidney disease and is managed using vitamin D replacement therapy. Very few studies have examined the effectiveness of pulse alfacalcidol therapy in comparison to daily oral alfacalcidol therapy in suppressing serum parathyroid hormone (PTH) levels in hemodialysis patients. The aim of this randomized controlled trial was to replicate the findings of prior studies comparing effectiveness of pulse oral alfacalcidol therapy versus daily oral alfacalcidol therapy in suppressing PTH after 13 weeks of therapy using a Palestinian sample of hemodialysis patients, and to identify demographic and biomedical characteristics of patients that are independently associated with PTH levels.

METHODS

One hundred and sixty-seven patients completed the study, 88 in the daily group and 79 in the pulse group. The pulse group had more clinically significant reduction in mean PTH level by 75 pg/dL at 13 weeks than the daily group, but this was not statistically significant.

RESULTS

The effect of alfacalcidol therapy on metabolism of phosphate and corrected calcium levels was comparable in both groups, and pulse therapy was not associated with increased risk of hypercalcemia and hyperphosphatemia. Serum PTH levels were independently and inversely associated with older age and diabetes.

CONCLUSION

Switching daily alfacalcidol therapy to thrice-weekly alfacalcidol pulse therapy seems safe and convenient, especially for hemodialysis patients with poor compliance with treatment. This study also highlights the importance of monitoring and preventing malnutrition in hemodialysis patients and maintaining optimal glycemic control in diabetic hemodialysis patients.

Bone Turnover Status: Classification Model and Clinical Implications

Aim: To develop a practical model for classification bone turnover status and evaluate its clinical usefulness. Methods: Our classification of bone turnover status is based on internationally recommended biomarkers of both bone formation (N-terminal propeptide of type1 procollagen, P1NP) and bone resorption (beta C-terminal cross-linked telopeptide of type I collagen, bCTX), using the cutoffs proposed as therapeutic targets. The relationships between turnover subtypes and clinical characteristic were assessed in1223 hospitalised orthogeriatric patients (846 women, 377 men; mean age 78.1±9.50 years): 451(36.9%) subjects with hip fracture (HF), 396(32.4%) with other non-vertebral (non-HF) fractures (HF) and 376 (30.7%) patients without fractures. Resalts: Six subtypes of bone turnover status were identified: 1 - normal turnover (P1NP>32 μg/L, bCTX≤0.250 μg/L and P1NP/bCTX>100.0[(median value]); 2- low bone formation (P1NP ≤32 μg/L), normal bone resorption (bCTX≤0.250 μg/L) and P1NP/bCTX>100.0 (subtype2A) or P1NP/bCTX<100.0 (subtype 2B); 3- low bone formation, high bone resorption (bCTX>0.250 μg/L) and P1NP/bCTX<100.0; 4- high bone turnover (both markers elevated ) and P1NP/bCTX>100.0 (subtype 4A) or P1NP/bCTX<100.0 (subtype 4B). Compared to subtypes 1 and 2A, subtype 2B was strongly associated with nonvertebral fractures (odds ratio [OR] 2.0), especially HF (OR 3.2), age>75 years and hyperparathyroidism. Hypoalbuminaemia and not using osteoporotic therapy were two independent indicators common for subtypes 3, 4A and 4B; these three subtypes were associated with in-hospital mortality. Subtype 3 was associated with fractures (OR 1.7, for HF OR 2.4), age>75 years, chronic heart failure (CHF), anaemia, and history of malignancy, and predicted post-operative myocardial injury, high inflammatory response and length of hospital stay (LOS) above10 days. Subtype 4A was associated with chronic kidney disease (CKD), anaemia, history of malignancy and walking aids use and predicted LOS>20 days, but was not discriminative for fractures. Subtype 4B was associated with fractures (OR 2.1, for HF OR 2.5), age>75 years, CKD and indicated risks of myocardial injury, high inflammatory response and LOS>10 days. Conclusions: We proposed a classification model of bone turnover status and demonstrated that in orthogeriatric patients altered subtypes are closely related to presence of nonvertebral fractures, comorbidities and poorer in-hospital outcomes. However, further research is needed to establish optimal cut points of various biomarkers and improve the classification model.