Pharmacological Management of Secondary Hyperparathyroidism in Patients with Chronic Kidney Disease

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.

The value of clinical-ultrasonographic feature model to predict the severity of secondary hyperparathyroidism

Objectives

To analyze conventional ultrasound (CUS) and contrast-enhanced ultrasound (CEUS) features in patients with secondary hyperparathyroidism (SHPT) and to evaluate the clinical-ultrasonographic feature based model for predicting the severity of SHPT.

Methods

From February 2016 to March 2021, a total of 59 patients (age 51.3 ± 11.7 years, seCr 797.8 ± 431.7 μmol/L, iPTH 1535.1 ± 1063.9 ng/L) with SHPT (including 181 parathyroid glands (PTGs)) without the history of intact parathyroid hormone (iPTH)-reducing drugs using were enrolled. The patients were divided into the mild SHPT group (mSHPT, iPTH <800 ng/L) and the severe SHPT group (sSHPT, iPTH ≥ 800 ng/L) according to the serum iPTH level. The clinical test data of patients were collected and CUS and CEUS examinations were performed for every patient. Multivariable logistic regression model according to clinical-ultrasonographic features was adopted to establish a nomogram. We performed K-fold cross-validation on this nomogram model and nomogram performance was determined by its discrimination, calibration, and clinical usefulness.

Results

There were 19 patients in the mSHPT group and 40 patients in the sSHPT group. Multivariable logistic regression indicated serum calcium, serum phosphorus and total volume of PTGs were independent predictors related with serum iPTH level. Even though CEUS score of wash-in and wash-out were showed related to severity of SHPT in univariate logistic regression analysis, they were not predictors of SHPT severity (p = 0.539, 0.474 respectively). The nomogram developed by clinical and ultrasonographic features showed good calibration and discrimination. The accuracy and the area under the curve (AUC), positive predictive value (PPV), negative predictive value (NPV) and accuracy of this model were 0.888, 92.5%, 63.2% and 83.1%, respectively. When applied to internal validation, the score revealed good discrimination with stratified fivefold cross-validation in the cohort (mean AUC = 0.833).

Conclusions

The clinical-ultrasonographic features model has good performance for predicting the severity of SHPT.

Market Consolidation and Innovation in US Dialysis

While patients with end-stage kidney disease have benefited from innovations in clinical therapeutics and care delivery, these changes have been primarily incremental and have not fundamentally transformed care delivery. Dialysis markets are highly concentrated, which may impede innovation. Unique features of the dialysis industry that have contributed to consolidation can help to explain links between consolidation and innovation. We discuss these unique features and then provide a framework for considering the effects of consolidation on innovation in dialysis that focuses on the following economic considerations: (1) industry characteristics, composition, and stage of consolidation, (2) innovation characteristics and relative profitability, (3) the role of government regulation, and (4) innovation from smaller providers and new entrants. We present examples of how these considerations have influenced the adoption of alternative dialysis technologies such as peritoneal dialysis and erythropoietin-stimulating agents, and we discuss how consolidated markets can both help and hinder recent policy initiatives to transform dialysis care delivery. Only by considering these important drivers of consolidation, future efforts can be successful in transforming end-stage kidney disease care.

Monthly fluctuations in 25-hydroxy-vitamin D levels in day and rotating night shift hospital workers

PURPOSE

Epidemiological studies have suggested that indoor hospital employees, either day or night shift workers, are at high risk of metabolic and cardiovascular diseases. Interestingly, previous reports have also described a higher prevalence of vitamin D (25OHD) deficiency among these workers. However, few studies have determined the monthly variations in 25OHD levels in indoor hospital employees.

METHODS

To address this lack of knowledge, in 2018, during the periodic health surveillance checks at the Service of Occupational Medicine, we measured 25OHD levels in a group of indoor hospital workers (88 rotating night shift workers vs 200 day workers). Each participant received a single annual health surveillance check.

RESULTS

The mean levels of 25OHD were consistently below the lower limit of the normal range in both groups throughout the year. Only in the summer, day workers but not rotating night shift workers (mean 25.9 ± 11.3 ng/ml vs 23.1 ± 9.1 ng/ml; p = 0.042) showed levels significantly higher than those in the other seasons. This difference remained statistically significant even after correction for study covariates [β = -  1.649 (CI - 0.283/- 3.482), p = 0.039]. A cosinor analysis confirmed that the difference in the 25OHD levels between groups was present later in the year.

CONCLUSIONS

We found that relatively young healthy hospital workers, especially those with rotating night shifts, in the absence of significant metabolic risk factors, have a high risk of 25OHD deficiency/insufficiency. Because 25OHD deficiency may lead to a progression to more severe conditions such as osteoporosis or bone fractures, our results should be verified in larger cohorts including different ancestries.

Phosphate acts directly on the calcium-sensing receptor to stimulate parathyroid hormone secretion

Extracellular phosphate regulates its own renal excretion by eliciting concentration-dependent secretion of parathyroid hormone (PTH). However, the phosphate-sensing mechanism remains unknown and requires elucidation for understanding the aetiology of secondary hyperparathyroidism in chronic kidney disease (CKD). The calcium-sensing receptor (CaSR) is the main controller of PTH secretion and here we show that raising phosphate concentration within the pathophysiologic range for CKD significantly inhibits CaSR activity via non-competitive antagonism. Mutation of residue R62 in anion binding site-1 abolishes phosphate-induced inhibition of CaSR. Further, pathophysiologic phosphate concentrations elicit rapid and reversible increases in PTH secretion from freshly-isolated human parathyroid cells consistent with a receptor-mediated action. The same effect is seen in wild-type murine parathyroid glands, but not in CaSR knockout glands. By sensing moderate changes in extracellular phosphate concentration, the CaSR represents a phosphate sensor in the parathyroid gland, explaining the stimulatory effect of phosphate on PTH secretion.

Elevated inorganic phosphate levels promote excessive parathyroid hormone secretion, which contributes to the aetiology of secondary hyperparathyroidism. Here, the authors show that phosphate directly inhibits the calcium-sensing receptor, the main regulator of parathyroid hormone secretion.

Therapeutic experience of severe and recurrent secondary hyperparathyroidism in a patient on hemodialysis for 18 years: A case report

INTRODUCTION

For patients with refractory secondary hyperparathyroidism (SHPT), parathyroidectomy (PTX) has received increasing attention. However, evidence-based medicine shows that there is still controversy regarding surgical methods, efficacy, and safety. We retrospectively analyzed the process of diagnosis and treatment in one patient with severe SHPT and long-term chronic renal failure (CRF), so as to further improve the therapeutic effect.

CASE PRESENTATION

A 61-year-old female with SHPT and CRF manifested as no urine for 18 years, underwent PTX 4 times since September 2010, with satisfactory final recovery. The first operation involved resection of 3 parathyroid glands in the normal position; the second operation involved removal of an ectopic parathyroid gland, combined with parathyroid gland autotransplantation; the third operation was performed to resect suspected recurrent parathyroid gland; the fourth operation involved partial excision of the autotransplanted parathyroid glands.

CONCLUSION

Accurate preoperative localized diagnosis and optimal surgical approach play key roles in the prevention and treatment of SHPT; postoperative recurrence of SHPT caused by ectopic or autotransplanted parathyroid gland should receive more attention.

Managing diabetic kidney disease

INTRODUCTION

Diabetes mellitus (DM) is the leading cause of chronic kidney disease (CKD). This review covers the pillars of care essential for the management of diabetic kidney disease (DKD) including (1) early diagnosis, (2) improved glycaemic control, (3) treatment of hypertension, (4) identification and treatment of associated metabolic bone disease and (5) identification and effective management of dyslipidaemia and additional cardiovascular risk factors.

SOURCES OF DATA

We searched PubMed for articles using search terms: diabetic nephropathy, diabetic kidney disease, diabetes and chronic kidney disease. We used clinical guidelines from NICE, the Association of British Clinical Diabetologists (ABCD), the Joint British Societies (JBS) and the Kidney Disease: Improving Global Outcomes (KDIGO) working group.

AREAS OF AGREEMENT

Multiple risk factor reduction targeting glycaemic control, blood pressure control, dyslipidaemia, smoking and management of obesity is important in preventing and in managing DKD.

AREAS OF CONTROVERSY

Guidelines disagree on the individualized glycaemic targets for patients with diabetic kidney disease.

GROWING POINTS

The growing number of patients with DKD is causing increased pressure on limited primary care and specialized services. New ways of managing patients using novel technology solutions are required.

AREAS TIMELY FOR DEVELOPMENT

The use of novel anti-hyperglycaemic agents, particularly sodium glucose co-transporter 2 inhibitors and GLP-1 receptor agonists, has been associated with a reduction in cardiovascular disease and DKD.

Formulation optimization and pharmacokinetics evaluation of oral self-microemulsifying drug delivery system for poorly water soluble drug cinacalcet and no food effect

The present research indicated that a new self-microemulsifying drug delivery systems (SMEDDS) were used to reduce the food effect of poorly water-soluble drug cinacalcet and enhance the bioavailability in beagle dogs by oral gavage. Ethyl oleate, OP-10, and PEG-200 was selected as the oil phase, surfactant and co-surfactant of cinacalcet-SMEDDS by the solubility and phase diagram studies. Central Composite Design-Response Surface Methodology was used to determine the ratio of surfactant and co-surfactant, the amount of oil for optimizing the SMEDDS formation. The prepared formulations were further characterized by the droplet size, self-microemulsifying time, zeta potential, polydispersity index (PDI), and robustness to dilution. The in vitro release profile of cinacalcet-SMEDDS was determined in four different release medium and in fasted state and fed state of simulated gastrointestinal fluid. Cinaclcet-SMEDDS were implemented under fed and fasted state in dogs and product REGPARA^® was used as a comparison to the prepared formulation in the pharmacokinetics. The result showed the components of SMEDDS, the amount of oil, the ratio of surfactant, and co-surfactant was optimized using solubility, pseudo-ternary phase diagram studies, and response surface methodology. In vitro drug release studies indicated that the cinacalcet-SMEDDS eliminated the effect of pH variability in release medium and variational gastroenteric environments with improved drug release performance. Pharmacokinetic studies revealed that the profiles of cinacalcet-SMEDDS were similar both in the fasted and fed state compared with commercial product, indicating the formulation significantly promoted the absorption, enhanced bioavailability and had no food effect essentially. It is concluded that poorly water-soluble drug cinacalcet was improved in the solubility and bioavailability by using a successful oral dosage form the SMEDDS, and eliminated food effect as well.