Comparative effects of calcitriol and calcimimetic on bone health in renal insufficiency.

Calcitriol and calcimimetics are used to treat hyperparathyroidism secondary to chronic kidney disease (CKD). Calcitriol administration and the subsequent increase in serum calcium concentration decrease parathyroid hormone (PTH) levels, which should reduce bone remodeling. We have previously reported that, when maintaining a given concentration of PTH, the addition of calcimimetics is associated with an increased bone cell activity. Whether calcitriol administration affects bone cell activity while PTH is maintained constant should be evaluated in an animal model of renal osteodystrophy. The aim of the present study was to compare in CKD PTH-clamped rats the bone effects of calcitriol and calcimimetic administration. The results show that the administration of calcitriol and calcimimetic at doses that induced a similar reduction in PTH secretion produced dissimilar effects on osteoblast activity in 5/6 nephrectomized (Nx) rats with secondary hyperparathyroidism and in Nx rats with clamped PTH. Remarkably, in both rat models, the administration of calcitriol decreased osteoblastic activity, whereas calcimimetic increased bone cell activity. In vitro, calcitriol supplementation inhibited nuclear translocation of ß-catenin and reduced proliferation, osteogenesis, and mineralization in mesenchymal stem cells differentiated into osteoblasts. In conclusion, besides the action of calcitriol and calcimimetics at parathyroid level, these treatments have specific effects on bone cells that are independent of the PTH level.

Capsiate ameliorates secondary hyperparathyroidism by improving insulin sensitivity and inhibiting angiogenesis.

Secondary hyperparathyroidism has a significant impact on the overall well-being of the body. Capsiates, known for their antioxidant and metabolic properties, have emerged as a promising alternative treatment for secondary hyperparathyroidism. This study aims to evaluate the effects and mechanisms of capsiates in the treatment of secondary hyperparathyroidism. To achieve our research objectives, we conducted a study on patients' serum and examined changes in metabolic markers using serum metabolomics. We induced secondary hyperparathyroidism in rat through dietary intervention and divided them into four groups. The first group, referred to as the Parathyroid Hormone (PTH) group, received a low-calcium and high-phosphate diet (0.2% calcium, 1.2% phosphorus). The second group served as the control group, receiving a standard phosphate and calcium diet (0.6% calcium, 0.6% phosphorus). The third group, called the capsiates group, consisted of rat from the control group treated with capsiates (intraperitoneal injection of 2 mg/kg capsiates for 2 weeks after 2 weeks of dietary intervention). The fourth group was the capsiates-treated PTH group. Subsequently, we conducted ribose nucleic acid (RNA) sequencing on parathyroid gland cells and evaluated serum thyroxine levels, oxidative stress, expression of proteins associated with vascular neogenesis, measurement of SOD, GSH and 3-nitrotyrosine, micro-CT and histological staining. The serum metabolomic data revealed a significant decrease in capsiate levels in the secondary hyperparathyroidism group. Administration of capsiates to PTH rat resulted in increased calcium levels compared to the PTH group. Additionally, the PTH + Capsiates group showed significantly lower levels of PTH and phosphate compared to the PTH group. The PTH group exhibited a notable increase in the quantity and size of mitochondria compared to the control group. Following capsiates administration to the PTH group, there was a significant reduction in the number of mitochondria and length of microvilli, but an increase in the size of mitochondria compared to the PTH group. Sequencing analysis revealed that vascular endothelial growth factor (VEGF) and Vascular Endothelial Growth Factor Receptor 1 (VEGFR1) play crucial roles in this process. Vascular-related variables and downstream signalling were significantly elevated in hyperthyroidism and were alleviated with capsaicin treatment. Finally, combining capsiates with the PTH group improved bone mineral density, Tb.N, BV.TV, Cs.Th, Tt.Ar, OPG, Ob.TV and Oc.TV, as well as the mineral apposition rate, but significantly decreased Tb.Sp and Receptor Activator for Nuclear Factor-κ B Ligand (RANKL) compared to the PTH group. The findings suggest that capsiates can improve secondary hyperparathyroidism and ameliorated osteoporosis outcomes by inhibiting angiogenesis and reducing oxidative stress.

Skeletal parathyroid hormone hyporesponsiveness: a neglected, but clinically relevant reality in chronic kidney disease.

PURPOSE OF REVIEW: Defining the optimal parathyroid hormone (PTH) target in chronic kidney disease (CKD) is challenging, especially for bone outcomes, due to the substantial variability in the skeleton's response to PTH. Although PTH hyporesponsiveness is as integral a component of CKD-mineral bone disorder as elevated PTH levels, clinical awareness of this condition is limited. In this review, we will discuss factors and mechanisms contributing to PTH hyporesponsiveness in CKD. This knowledge may provide clues towards a personalized approach to treating secondary hyperparathyroidism in CKD. RECENT FINDINGS: Indicates a link between disturbed phosphate metabolism and impaired skeletal calcium sensing receptor signaling as an important mediator of PTH hyporesponsiveness in CKD. Further, cohort studies with diverse populations point towards differences in mineral metabolism control, rather than genetic or environmental factors, as drivers of the variability of PTH responsiveness. IN SUMMARY: Skeletal PTH hyporesponsiveness in CKD has a multifactorial origin, shows important interindividual variability, and is challenging to estimate in clinical practice. The variability in skeletal responsiveness compromises PTH as a biomarker of bone turnover, especially when considering populations that are heterogeneous in ethnicity, demography, kidney function, primary kidney disease and mineral metabolism control, and in patients treated with bone targeting drugs.

Impact of Parathyroidectomy Versus Oral Cinacalcet on Bone Mineral Density in Patients on Peritoneal Dialysis With Advanced Secondary Hyperparathyroidism: The PROCEED Pilot Randomized Trial.

RATIONALE & OBJECTIVE: Parathyroidectomy and calcimimetics have been used to reduce fracture risk in patients with kidney failure and advanced secondary hyperparathyroidism (SHPT), but direct comparisons of these treatment approaches have not been implemented. This pilot study compared their effects on bone mineral density (BMD) in this patient population. STUDY DESIGN: A prospective pilot open-label randomized trial. SETTING & PARTICIPANTS: 65 patients receiving maintenance peritoneal dialysis with advanced SHPT recruited from 2 university-affiliated hospitals in Hong Kong. INTERVENTIONS: Total parathyroidectomy with forearm autografting versus oral cinacalcet treatment for 12 months. OUTCOME: Prespecified secondary end points including changes in BMD z and T scores of femoral neck, lumbar spine, and distal radius 12 months after treatment initiation and also categorized as osteopenia or osteoporosis according to the World Health Organization. RESULTS: Both total parathyroidectomy and cinacalcet significantly improved BMD of the lumbar spine and femoral neck over 12 months, but the total parathyroidectomy group had a greater increase than the cinacalcet-treated group (P<0.001). The proportion of study participants classified as having osteopenia/osteoporosis by femoral neck T-score fell from 78.2% to 51.7% in the total parathyroidectomy group (P<0.001) and from 65.7% to 52.0% in cinacalcet-treated group after 12 months (P=0.7). The proportion of participants with a T-score at the lumbar spine classified as osteopenia/osteoporosis fell from 53.1% to 31.0% in the total parathyroidectomy group (P=0.01) and from 59.4% to 53.8% with cinacalcet (P=0.3). No significant change was observed in BMD T or z score of the distal radius over 12 months with either intervention. LIMITATIONS: Bone histology was not assessed, and the study duration was 12 months. CONCLUSIONS: A large proportion of peritoneal dialysis patients with advanced SHPT had low bone densities and osteopenia/osteoporosis. Total parathyroidectomy increased the BMD of the lumbar spine and femoral neck and reduced osteopenia/osteoporosis more than oral cinacalcet. FUNDING: Grants from academic (The University of Hong Kong Research) and not-for-profit (Hong Kong Society of Nephrology) entities. REGISTRATION: Registered at Clinicaltrials.gov with study number NCT01447368. PLAIN-LANGUAGE SUMMARY: It is not known whether oral cinacalcet and surgical parathyroidectomy differ in their effects on bone parameters in patients with advanced secondary hyperparathyroidism (SHPT) receiving peritoneal dialysis. This pilot randomized trial evaluated the effect of medical versus surgical therapy on bone mineral densities (BMD) as prespecified secondary study end points. The findings showed that a large proportion of peritoneal dialysis patients with advanced SHPT had low bone densities and osteopenia/osteoporosis. Parathyroidectomy increased the BMD of the lumbar spine and femoral neck more than cinacalcet over 12 months. Parathyroidectomy reduced the proportion of patients with osteopenia/osteoporosis at the lumbar spine and femoral neck more than cinacalcet after 12 months. Neither intervention led to an increase in the BMD of the distal radius over 12 months.

Comparative Effectiveness of Alternative Treatment Approaches to Secondary Hyperparathyroidism in Patients Receiving Maintenance Hemodialysis: An Observational Trial Emulation.

RATIONALE & OBJECTIVE: Optimal approaches to treat secondary hyperparathyroidism (SHPT) in patients on maintenance hemodialysis (HD) have yet to be established in randomized controlled trials (RCTs). STUDY DESIGN: Two observational clinical trial emulations. SETTING & PARTICIPANTS: Both emulations included adults receiving in-center HD from a national dialysis organization. The patients who had SHPT in the period between 2009 and 2014, were insured for≥180 days by Medicare as primary payer, and did not have contraindications or poor health status limiting theoretical trial participation. EXPOSURE: The parathyroid hormone (PTH) Target Trial emulation included patients with new-onset SHPT (first PTH 300-600pg/mL), with 2 arms defined as up-titration of either vitamin D sterols or cinacalcet within 30 days (lower target) or no up-titration (higher target). The Agent Trial emulation included patients with a PTH≥300 pg/mL while on≥6µg weekly of vitamin D sterol (paricalcitol equivalent dose) and no prior history of cinacalcet. The 2 arms were defined by the first dose or agent change within 30 days (vitamin D-favoring [vitamin-D was up-titrated] vs cinacalcet-favoring [cinacalcet was added] vs nondefined [neither applies]). Multiple trials per patient were allowed in trial 2. OUTCOME: The primary outcome was all-cause death over 24 months; secondary outcomes included cardiovascular (CV) hospitalization or the composite of CV hospitalization or death. ANALYTICAL APPROACH: Pooled logistic regression. RESULTS: There were 1,152 patients in the PTH Target Trial (635 lower target and 517 higher target). There were 2,726 unique patients with 6,727 patient trials in the Agent Trial (6,268 vitamin D-favoring trials and 459 cinacalcet-favoring trials). The lower PTH target approach was associated with reduced adjusted hazard of death (HR, 0.71 [95% CI, 0.52-0.93]), CV hospitalization (HR, 0.78 [95% CI, 0.63-0.98]), and their composite (HR, 0.74 [95% CI, 0.61-0.89]). The cinacalcet-favoring approach demonstrated lower adjusted hazard of death compared to the vitamin D-favoring approach (HR, 0.79 [95% CI, 0.62-0.99]), but not of CV hospitalization or the composite outcome. LIMITATIONS: Potential for residual confounding; low use of cinacalcet with low power. CONCLUSIONS: SHPT management that is focused on lower PTH targets may lower mortality and CV disease in patients receiving HD. These findings should be confirmed in a pragmatic randomized trial. PLAIN-LANGUAGE SUMMARY: Optimal approaches to treat secondary hyperparathyroidism (SHPT) have not been established in randomized controlled trials. Data from a national dialysis organization was used to identify patients with SHPT in whom escalated treatment may be indicated. The approach to treatment was defined based on observed upward titration of SHPT-controlling medications: earlier titration (lower target) versus delayed titration (higher target); and the choice of medication (cinacalcet vs vitamin D sterols). In the first trial emulation, we estimated a 29% lower rate of death and 26% lower rate of cardiovascular disease or death for patients managed with a lower versus higher target approach. Cinacalcet versus vitamin D-favoring approaches were not consistently associated with outcomes in the second trial emulation. This observational study suggests the need for additional clinical trials of SHPT treatment intensity.

Cost-Effectiveness and Clinical Outcomes of Secondary Hyperparathyroidism Treatments in Patients with Chronic Kidney Disease.

The study addresses the challenge of treating secondary hyperparathyroidism (SHPT) in chronic kidney disease (CKD) patients, focusing on the cost-effectiveness of surgical versus pharmacological interventions. Conducting a retrospective analysis on 152 CKD patients with SHPT at the Third People's Hospital of Chengdu, the study matched 80 patients into two groups: 40 undergoing parathyroidectomy with autotransplantation (PTX + AT) and 40 treated with calcimimetics. PTX + AT was more effective in alleviating symptoms, particularly bodily pain, and demonstrated greater cost-effectiveness over a long-term period compared to calcimimetics. This was especially significant in patients with PTH levels > 1800 pg/mL and hyperphosphatemia. Despite similar initial costs, PTX + AT led to a substantial decrease in expenses during the 2-5 years post-treatment period, PTX + AT results in an ICER of -RMB 26.71/QALY for the first post-treatment year and -RMB-111.9k/QALY for the 2-5 year period, indicating cost-effectiveness with reduced long-term costs. The study also found an increased economic burden in managing patients with hyperphosphatemia. Surgical intervention (PTX + AT) is advocated as the primary treatment strategy for severe SHPT in CKD patients, owing to its long-term economic and clinical advantages. The results underscore the need for a severity-based approach in treating SHPT.

Effects of evocalcet on parathyroid calcium-sensing receptor and vitamin D receptor expression in uremic rats.

Little is known about the effect of the recently developed calcimimetic evocalcet (Evo) on parathyroid calcium-sensing receptor (CaSR) and vitamin D receptor (VDR) expression. We examined the effects of Evo and cinacalcet (Cina) on CaSR and VDR expression in 5/6 nephrectomized Sprague-Dawley rats fed a high-phosphorus diet for 4 weeks to develop secondary hyperparathyroidism (SHPT). These uremic rats were divided into 4 groups-baseline control (Nx4W) and groups with additional treatment with either the Vehicle, Evo, or Cina for 2 weeks; normal rats were used as normal controls (NC). Blood parameters and parathyroid tissue were analyzed. CaSR and VDR expression levels were determined using immunohistochemistry. The degree of kidney injury and hyperphosphatemia was similar in the uremic groups (Nx4W, Vehicle, Cina, and Evo). Serum parathyroid hormone levels were significantly higher in the Nx4W and Vehicle groups than in the NC group. This increase was significantly suppressed in the Cina and Evo groups compared with that in the Vehicle group. Serum calcium levels were significantly and equally lower in the Cina and Evo groups relative to those in the Vehicle group. CaSR expression was significantly lower in the Nx4W and Vehicle groups than in the NC group. This downregulation was of an equally lesser magnitude in the Cina and Evo groups. A similar trend was observed for VDR expression. These results indicate that Evo and Cina treatment can increase parathyroid CaSR and VDR expression in uremic rats with SHPT, which could provide better control of mineral and bone disorder markers.

Effectiveness of calcimimetics on fractures in dialysis patients with secondary hyperparathyroidism: meta-analysis of randomized trials.

INTRODUCTION: This study aimed to assess the effectiveness of calcimimetics in reducing the risk of fractures in dialysis patients with secondary hyperparathyroidism (SHPT). MATERIAL AND METHODS: A comprehensive literature search was conducted using PubMed, Embase, and Cochrane Library for articles published through December 9, 2023. The quality of each trial was evaluated using the Cochrane Collaboration tool. Meta-analysis was performed using a random-effects model, and effect measures across studies were synthesized. The risk ratio (RR) and 95% confidence interval (CI) were used to quantify the risk of fracture. RESULTS: We identified seven studies involving 6481 dialysis patients with SHPT. The administration of calcimimetics reduced fracture incidence compared to placebo or conventional treatment (RR: 0.50, 95% CI 0.29-0.88, p = 0.02). Calcimimetics demonstrated a low number needed to treat (NNT) to prevent an incident fracture (NNT: 47). CONCLUSION: The use of calcimimetics offers a significant benefit in reducing the risk of fractures in patients undergoing dialysis with SHPT.

Effects of active vitamin D analogs and calcimimetic agents on PTH and bone mineral biomarkers in hemodialysis patients with SHPT: a network meta-analysis.

OBJECTIVE: Active vitamin D analogs and calcimimetic agents are primary drugs for patients with secondary hyperparathyroidism. Due to the different pharmacological mechanisms, they have different effects on the level of parathyroid hormone, serum calcium, phosphorus, and bone turnover biomarkers. This study aimed to evaluate the active vitamin D analogs and calcimimetic agents in hemodialysis patients with secondary hyperparathyroidism. METHODS: We included randomized clinical trials of hemodialysis patients with secondary hyperparathyroidism, comparing active vitamin D analogs to calcimimetic agents or placebo/control. The primary outcome was the change of PTH level from baseline to end-up. The secondary outcome was the change in serum calcium, phosphorus, calcium-phosphorus product, and bone turnover biomarkers. A network meta-analysis method was applied to complete this study. The forest plots reflected statistical differences in the outcomes between active vitamin D analogs and calcimimetic agents. The SUCRA result presented the ranking of impact on the outcomes. RESULTS: Twenty-one randomized clinical trials with 4653 patients were included in this network meta-analysis. Global and splitting-node inconsistencies provided no evidence of inconsistency in this study. There was no statistical difference between two active vitamin D analogs and three calcimimetic agents in the PTH, and phosphorus levels changed. Considering serum calcium level, compared with placebo, calcitriol (9.73, 3.09 to 16.38) and paricalcitol (9.74, 3.87 to 15.60) increase serum calcium. However, cinacalcet (- 1.94, - 3.72 to - 0.15) and etelcalcetide (- 7.80, - 11.80 to - 3.80) reduced the serum calcium, even a joint use of cinacalcet with active vitamin D analogs (- 5.83, - 9.73 to - 1.93). Three calcimimetic agents decreased calcium levels much more than calcitriol and paricalcitol. The same type of drugs was not distinct, with each one affecting the change in calcium level. Cinacalcet reduced calcium-phosphorus product much more than paricalcitol (- 3.66, - 6.72 to - 0.60). Evocalcet decreased calcium-phosphorus product more than cinacalcet (- 5.64, - 8.91 to - 2.37), calcitriol (- 9.36, - 14.81 to - 3.92), and paricalcitol (- 9.30, - 13.78 to - 4.82). Compared with paricalcitol, cinacalcet significantly increases the level of ALP (24.50, 23.05 to 25.95) and bALP (0.67, 0.03 to 1.31). The incidence of gastrointestinal disorders in cinacacet (29.35, 1.71 to 504.98) and etelcalcetide (20.92, 1.20 to 365.68) was notably higher than in paricalcitol. Etelcalcetide (0.71, 0.53 to 0.96) and evocalcet (0.46, 0.33 to 0.64) presented a lower rate of gastrointestinal disorders than cinacalcet. Cinacalcet ranked first in adverse gastrointestinal, nervous, and respiratory reactions. CONCLUSION: The same kinds of agents perform similar efficacy on the level of PTH, serum calcium, phosphorus, and calcium-phosphorus product. Paricalcitol did not lead to more hypercalcemia than calcitriol. The calcium decrease induced by cinacalcet was not settled even by associating it with active vitamin D analogs. Cinacalcet and evocalcet were superior to calcitriol and paricacitol in reducing calcium-phosphorus product. Calcimimetics induced more gastrointestinal disorders than active vitamin D analogs, especially cinacalcet.

The Effects of Parathyroidectomy vs Medical Treatments for Secondary Hyperparathyroidism in Patients Undergoing Dialysis: A Meta-Analysis.

OBJECTIVE: The management of secondary hyperparathyroidism in patients undergoing dialysis is debated, with uncontrolled parathyroid hormone (PTH) levels becoming more common despite the expanded use of medical treatments like cinacalcet. This study examines the clinical benefits of parathyroidectomy vs medical treatment in reducing mortality and managing key laboratory parameters in patients undergoing dialysis. METHODS: PubMed, Embase, Cochrane, Scopus, and Web of Science databases were searched for cohort studies or randomized controlled trials published before August 18, 2023. We included studies with comparative arms, specifically medical treatment vs surgical intervention. Patients with a history of kidney transplant were excluded. Outcomes were analyzed using hazard ratios (HRs) for mortality and weighted mean differences (WMD) for laboratory parameters. RESULTS: Twenty-three studies involving 24 398 patients were analyzed. The pooled meta-analysis has shown a significant reduction in all-cause (HR, 0.47; 95% confidence interval [CI], 0.35-0.61) and cardiovascular mortality (HR, 0.58; 95% CI, 0.40-0.84) for parathyroidectomy vs medical treatments. Subgroup analysis showed that parathyroidectomy was associated with a greater reduction in mortality in patients with a PTH level over 585 pg/mL (HR, 0.37; 95% CI, 0.24-0.58). No mortality difference was found when all patients in the medical group received cinacalcet alongside standard medical treatment (HR, 1.02; 95% CI, 0.49-2.11). Parathyroidectomy also led to a larger decrease in PTH (WMD, 1078 pg/mL; 95% CI, 587-1569), calcium (WMD, 0.86 mg/dL; 95% CI, 0.43-1.28), and phosphate (WMD, 0.74 mg/dL; 95% CI, 0.32-1.16). CONCLUSION: Parathyroidectomy may offer a survival advantage compared to medical management in patients with severe secondary hyperparathyroidism.

Pharmaceutical Management of Secondary Hyperparathyroidism and the Role of Surgery: A 5-Year Retrospective Study.

Background and Objectives: Secondary hyperparathyroidism (SHPT) poses a common condition among patients with chronic kidney disease (CKD) due to the chronic stimulation of the parathyroid glands as a result of persistently low calcium levels. As a first option for medical treatment, vitamin D receptor analogs (VDRAs) and calcimimetic agents are generally used. Apart from cinacalcet, which is orally taken, in recent years, another calcimimetic agent, etelcalcetide, is being administered intravenously during dialysis. Materials and Methods: In a 5-year retrospective study between 2018 and 2023, 52 patients undergoing dialysis were studied. The aim of this study is to highlight the possible effects and/or benefits that intravenously administered calcimimetic agents have on CKD patients. A total of 34 patients (65.4%) received cinacalcet and etelcalcetide while parathormone (PTH) and calcium serum levels were monitored on a monthly basis. Results: A total of 29 out of 33 patients (87.9%) that received treatment with etelcalcetide showed a significant decrease in PTH levels, which rose up to 57% compared to the initial values. None of the included patients needed to undergo parathyroidectomy (PTx) due to either extremely high and persistent PTH levels or severe side effects of the medications. It is generally strongly advised that parathyroidectomies should be performed by an expert surgical team. In recent years, a significant decrease in parathyroidectomies has been recorded globally, a fact that is mainly linked to the constantly wider use of new calcimimetic agents. This decrease in parathyroidectomies has resulted in an important decrease in complications occurring in cervical surgeries (e.g., perioperative hemorrhage and nerve damage). Conslusions: Despite the fact that these surgical complications cannot be easily compared to the pharmaceutical side effects, the recorded decrease in parathyroidectomies is considered to be notable, especially in cases of relapse where a difficult reoperation would be considered based on previously published guidelines.

Parathyroidectomy and Cinacalcet Use in Medicare-Insured Kidney Transplant Recipients.

RATIONALE & OBJECTIVE: Posttransplant hyperparathyroidism is common, and treatment practices are poorly characterized. The goal of this study was to examine the incidence, associations, and outcomes of posttransplant parathyroidectomy and calcimimetic use in a cohort of Medicare-insured US kidney transplant recipients. STUDY DESIGN: Retrospective observational cohort study. SETTING & PARTICIPANTS: We used the US Renal Data System to extract demographic, clinical, and prescription data from Medicare Parts A, B, and D-insured patients who received their first kidney transplant in 2007-2013. We excluded patients with pretransplant parathyroidectomy. PREDICTORS: Calendar year of transplantation and pretransplant patient characteristics. OUTCOME: (1) Incidence of and secular trends in parathyroidectomy and cinacalcet use in the 3 years after transplant; (2) 90-day outcomes after posttransplant parathyroidectomy and cinacalcet initiation. ANALYTICAL APPROACH: Temporal trends and pretransplant correlates of parathyroidectomy and cinacalcet use were assessed using proportional hazards models and multivariable Poisson regression, respectively. RESULTS: The inclusion criteria were met by 30,127 patients, of whom 10,707 used cinacalcet before transplant, 551 underwent posttransplant parathyroidectomy, and 5,413 filled≥1 prescription for cinacalcet. The rate of posttransplant parathyroidectomy was stable over time. By contrast, cinacalcet use increased during the period studied. Long dialysis vintage and pretransplant cinacalcet use were strongly associated with posttransplant parathyroidectomy and cinacalcet use. Roughly 1 in 4 patients were hospitalized within 90 days of posttransplant parathyroidectomy, with hypocalcemia-related diagnoses being the most common complication. Parathyroidectomy (vs cinacalcet initiation) was not associated with an increase in acute kidney injury. LIMITATIONS: We lacked access to laboratory data to help assess the severity of secondary/tertiary hyperparathyroidism. The cohort was limited to Medicare beneficiaries. CONCLUSIONS: Almost one-fifth of our study cohort was treated with parathyroidectomy and/or cinacalcet. Further studies are needed to establish the optimal treatment for posttransplant hyperparathyroidism.

Treatment of secondary hyperparathyroidism in non-dialysis CKD: an appraisal 2022s.

The situation of secondary hyperparathyroidism (SHPT) in chronic kidney disease patients not on dialysis (ND-CKD) is probably best characterised by the Kidney Disease: Improving Global Outcomes Chronic Kidney Disease-Mineral and Bone Disorder Update 2017 guideline 4.2.1 stating that the optimal parathyroid hormone levels are not known in these stages. Furthermore, new caution became recommended with regard to the routine use of active vitamin D analogues in early CKD stages and moderate SHPT phenotypes, due to their potential risks for hypercalcaemia and hyperphosphataemia aggravation. Nevertheless, there is still a substantial clinical need to prevent the development of parathyroid gland autonomy, with its associated consequences of bone and vascular damage, including fracture risks and cardiovascular events. Therefore we now attempt to review the current guideline-based and clinical practice management of SHPT in ND-CKD, including their strengths and weaknesses, favouring individualised approaches respecting calcium and phosphate homeostasis. We further comment on extended-release calcifediol (ERC) as a new differential therapeutic option now also available in Europe and on a potentially novel understanding of a required vitamin D saturation in more advanced CKD stages. There is no doubt, however, that knowledge gaps will remain unless powerful randomised controlled trials with hard and meaningful endpoints are performed.

Parathyroidectomy versus oral cinacalcet on cardiovascular parameters in peritoneal dialysis patients with advanced secondary hyperparathyroidism (PROCEED): a randomized trial.

BACKGROUND: This trial aimed to evaluate oral cinacalcet versus total parathyroidectomy (PTx) with forearm autografting on cardiovascular surrogate outcomes and health-related quality of life (HRQOL) measures in dialysis patients with advanced secondary hyperparathyroidism (SHPT). DESIGN: In this pilot prospective randomized trial conducted in two university-affiliated hospitals, 65 adult peritoneal dialysis patients with advanced SHPT were randomized to receive either oral cinacalcet or PTx. Primary endpoints were changes in left ventricular (LV) mass index by cardiac magnetic resonance imaging and coronary artery calcium scores (CACS) over 12 months. Secondary endpoints included changes in heart valves calcium scores, aortic stiffness, biochemical parameters of chronic kidney disease-mineral bone disease (CKD-MBD) and HRQOL measures over 12 months. RESULTS: Changes in LV mass index, CACS, heart valves calcium score, aortic pulse wave velocity and HRQOL did not differ between groups or within groups, despite significant reductions in plasma calcium, phosphorus and intact parathyroid hormone in both groups. Cinacalcet-treated patients experienced more cardiovascular-related hospitalizations than those who underwent PTx (P = .008) but the difference became insignificant after adjusting for baseline difference in heart failure (P = .43). With the same monitoring frequency, cinacalcet-treated patients had fewer hospitalizations due to hypercalcemia (1.8%) than patients who underwent PTx (16.7%) (P = .005). No significant changes were observed in HRQOL measures in either group. CONCLUSIONS: Both cinacalcet and PTx effectively improved various biochemical abnormalities of CKD-MBD and stabilized but did not reduce LV mass, coronary artery and heart valves calcification, or arterial stiffness, or improve patient-centered HRQOL measures in PD patients with advanced SHPT. Cinacalcet may be used in place of PTx for treating advanced SHPT. Long-term and powered studies are required to evaluate PTx versus cinacalcet on hard cardiovascular outcomes in dialysis patients. Trial registration: ClinicalTrials.gov identifier: NCT01447368.

Pre-operative Cinacalcet Administration Reduces Immediate Post-operative Hypocalcemia Following Total Parathyroidectomy in Severe Renal Hyperparathyroidism.

BACKGROUND: In severe renal hyperparathyroidism (RHPT), whether administrating Cinacalcet before total parathyroidectomy can reduce post-operative hypocalcemia remains unclear. We compared post-operative calcium kinetics between those who took Cinacalcet before surgery (Group I) and those who did not (Group II). METHODS: Patients with severe RHPT (defined by PTH ≥ 100 pmol/L) who underwent total parathyroidectomy between 2012 and 2022 were analyzed. Standardized peri-operative protocol of calcium and vitamin D supplementation was followed. Blood tests were performed twice daily in the immediate post-operative period. Severe hypocalcemia was defined as serum albumin-adjusted calcium < 2.00 mmol/L. RESULTS: Among 159 patients who underwent parathyroidectomy, 82 patients were eligible for analysis (Group I, n = 27; Group II, n = 55). Demographics and PTH levels before Cinacalcet administration were comparable (Group I: 169 ± 49 pmol/L vs Group II: 154 ± 45, p = 0.209). Group I had significantly lower pre-operative PTH (77 ± 60 pmol/L vs 154 ± 45, p < 0.001), higher post-operative calcium (p < 0.05), and lower rate of severe hypocalcemia (33.3% vs 60.0%, p = 0.023). Longer duration of Cinacalcet use correlated with higher post-operative calcium levels (p < 0.05). Cinacalcet use for > 1 year resulted in fewer severe post-operative hypocalcemia than non-users (p = 0.022, OR 0.242, 95% CI 0.068-0.859). Higher pre-operative ALP independently correlated with severe post-operative hypocalcemia (OR 3.01, 95% CI 1.17-7.77, p = 0.022). CONCLUSION: In severe RHPT, Cinacalcet led to significant drop in pre-operative PTH, higher post-operative calcium levels, and less frequent severe hypocalcemia. Longer duration of Cinacalcet use correlated with higher post-operative calcium levels, and the use of Cinacalcet for > 1 year reduced severe post-operative hypocalcemia.

Impact of Cinacalcet and Etelcalcetide on Bone Mineral and Cardiovascular Disease in Dialysis Patients.

PURPOSES OF REVIEW: With chronic kidney disease (CKD) progression, secondary hyperparathyroidism (sHPT) and mineral and bone metabolism disease (MBD) almost inevitably develop and result in renal osteodystrophy and cardiovascular disease (CVD). Together with active vitamin D, calcimimetics are the main therapy for sHPT in CKD. This review provides an overview of the therapeutic effects of oral cinacalcet and intravenous etelcalcetide on CKD-MBD and vascular disease, with a focus on pediatric dialysis patients. RECENT FINDINGS: Randomized controlled trials in adults and children demonstrate efficient lowering of parathyroid hormone (PTH) by the calcimimetics together with a reduction in serum calcium and phosphate when combined with low-dose active vitamin D, while therapy with active vitamin D analogs alone increases serum calcium and phosphate. Cinacalcet and etelcalcetide both improve bone formation and correct adynamic bone, i.e., have a direct bone anabolic effect. They decrease serum calciprotein particles, which are involved in endothelial dysfunction, atherogenesis, and vascular calcification. Clinical trials in adults suggest a modest slowing of the progression of cardiovascular calcification with cinacalcet. Calcimimetic agents represent a major pharmacological tool for improved control of CKD-MBD, by efficiently counteracting sHPT and allowing for better control of calcium/phosphate and bone homeostasis. Albeit definite evidence is lacking, the beneficial effects of calcimimetics on CVD are promising. Routine use of cinacalcet has been suggested in children.

Activation of the Calcium Receptor by Calcimimetic Agents Is Preserved Despite Modest Attenuating Effects of Hyperphosphatemia.

BACKGROUND: Phosphorus levels in the range seen clinically among patients undergoing dialysis have been reported to attenuate calcium receptor activation and modify parathyroid hormone (PTH) release from isolated parathyroid glands in vitro. Some clinicians and providers of dialysis thus have suggested that calcimimetic agents are ineffective and should not be used to manage secondary hyperparathyroidism among those undergoing dialysis when serum phosphorus concentrations exceed certain threshold levels. METHODS: To determine whether hyperphosphatemia diminishes the therapeutic response to calcimimetic agents, we used data from large clinical trials to analyze the effects of etelcalcetide and cinacalcet to lower plasma PTH levels in individuals on hemodialysis who had secondary hyperparathyroidism and varying degrees of hyperphosphatemia. RESULTS: Plasma PTH levels declined progressively during 26 weeks of treatment with either etelcalcetide or cinacalcet without regard to the degree of hyperphosphatemia at baseline. However, with each calcimimetic agent, the decreases in PTH from baseline were less at each interval of follow-up during the trials among participants with serum phosphorus levels above one of three prespecified threshold values compared with those with serum phosphorus levels below these thresholds. CONCLUSIONS: These in vivo findings are the first in humans to support the idea that hyperphosphatemia attenuates calcium receptor activation by calcium ions and by calcimimetic agents. The effect of hyperphosphatemia on the responsiveness to calcimimetic agents appears relatively modest, however, and unlikely to be significant therapeutically. The efficacy of treatment with calcimimetic agents for lowering plasma PTH levels among those with secondary hyperparathyroidism remains robust despite substantial elevations in serum phosphorus.

Upacicalcet Is a Novel Secondary Hyperparathyroidism Drug that Targets the Amino Acid Binding Site of Calcium-Sensing Receptor .

The human calcium-sensing receptor (CaSR) is a G protein-coupled receptor that maintains extracellular Ca2+ homeostasis by regulating the secretion of parathyroid hormone. Upacicalcet is a novel positive allosteric modulator of CaSR that is used for the treatment of secondary hyperparathyroidism. In the present study, to clarify the binding site of upacicalcet to CaSR, we conducted binding studies and agonistic activity studies in HEK-293T cells expressing human CaSR (intact and mutant) and an in silico docking-simulation analysis. As a result, upacicalcet competed with L-tryptophan and was thought to affect the amino acid binding site. In addition, the effects of substitutions at the amino acid binding site on the binding abilities to upacicalcet as well as the effects on receptor function as measured using inositol-1 monophosphate accumulation were examined. Upacicalcet interacted with several CaSR residues that constitute the amino acid binding site. Based on these results, we performed an in silico analysis and obtained a binding mode, consistent with the in vitro study results. Our study revealed that upacicalcet is a novel secondary hyperparathyroidism drug that targets the amino acid binding site of CaSR. Upacicalcet is expected to become a new treatment option for secondary hyperparathyroidism because the binding site differs from that of conventional drugs; consequently, it may be effective for patients who are not sensitive to conventional drugs, and it may have a superior safety profile. SIGNIFICANCE STATEMENT: Upacicalcet interacts with several residues that constitute the amino acid binding site of the calcium-sensing receptor (CaSR) and shows a potent positive allosteric activity. This mechanism differs from those of conventional drugs. Therefore, upacicalcet can be regarded as a novel secondary hyperparathyroidism drug that acts on the amino acid binding site of CaSR.

Cinacalcet and gastrointestinal bleeding risk in patients receiving hemodialysis.

PURPOSE: Secondary hyperparathyroidism (SHPT) is common among dialysis patients, and calcimimetics are a mainstay of treatment. This study assessed whether cinacalcet use is associated with gastrointestinal bleeding in a large hemodialysis cohort. METHODS: A linked database of clinical records and medical claims for patients receiving hemodialysis in a large dialysis organization, 2007-2010, was used. A nested case-control study was performed among patients aged ≥18 years who had received hemodialysis for ≥90 days, had Medicare Parts A, B, and D coverage for ≥1 year, and had clinical evidence of SHPT (parathyroid hormone >300 pg/mL). Cases were those who experienced death or hospitalization caused by gastrointestinal bleeding. Each case was matched to up to four controls. Exposure was measured by any cinacalcet use, current use, past use, cumulative exposure days, and cumulative dosage. Conditional logistic models were used to assess the association. RESULTS: Of 48 437 patients included, 2570 experienced gastrointestinal bleeding events (2498 non-fatal, 72 fatal), and 2465 (2397 non-fatal, 68 fatal) were matched to 9500 controls; 17.2% of cases and 15.8% of controls had cinacalcet exposure and 11.1% of both cases and controls had current use. The adjusted odds ratios (95% CI) of gastrointestinal bleeding for any use, current use, and past use of cinacalcet were 1.04 (0.91-1.19), 0.97 (0.83-1.13), and 1.22 (0.99-1.50), respectively, with no use as the reference. CONCLUSION: The results do not suggest an elevated risk of gastrointestinal bleeding resulting in hospitalization or death for hemodialysis patients exposed to cinacalcet.

Effect of vitamin D sterols on bone histology in pre-dialysis patients: A prospective controlled study.

BACKGROUND: Abnormalities related to mineral and bone metabolism are a common finding in chronic kidney disease (CKD). Vitamin D compounds are often prescribed to CKD patients with the purpose to control secondary hyperparathyroidism and reduce the risk of high-turnover bone disease. However, data on the effect of vitamin D sterols on bone histology in non-dialysis CKD is limited. MATERIALS AND METHODS: A prospective controlled study was conducted on a cohort of 56 patients with CKD stages 3 and 4. 19 patients on calcitriol and 12 patients on cholecalciferol were compared to a group of 25 age- and sex-matched controls. Participants underwent a tetracycline double-labelled transiliac bone biopsy before starting therapy and again 12 months later. Changes from baseline in circulating biomarkers and bone histomorphometric parameters were analyzed. RESULTS: Low-turnover bone disease was the most common pattern of renal osteodystrophy on the initial biopsy. There was no difference in biochemical or histomorphometric values between the three study groups at baseline. Serum intact parathormone (iPTH) and bone formation rate decreased significantly in calcitriol-treated patients, with prevalence of low-turnover bone disease doubling from baseline. In contrast, no significant changes were noted in cholecalciferol-treated and control subjects. CONCLUSION: Calcitriol was effective in preventing secondary hyperparathyroidism and high-turnover bone disease. However, it was associated with an increased risk of developing or aggravating low-turnover bone disease. In the absence of a bone biopsy, calcitriol use in pre-dialysis CKD should be reserved for patients with a progressive rise in iPTH levels, in whom high-turnover bone disease is suspected.